fluid friction apparatus final!!

POLYTECHNIC UNIVERSITY OF PUERTO RICO

DEPARTMENT OF CHEMICAL ENGINEERING

SAN JUAN, PUERTO RICO

CHE 4111/14

FLUID FRICTION APPARATUS

_____________________ MAYLA R. GONZÁLEZ RAMOS #53557

_____________________ ASHLYIE A. DÁVILA #51818

_____________________ MIGDELÍS HUERTAS #52336

EXPERIMENT DATE: JANUARY 3, 2011

DUE DATE: FEBRUARY 17, 2011

PROF. ZULEICA LOZADA

i

Abstract

In the Fluid Friction Apparatus experiment we studied flow, flow measurement techniques and

losses in a wide variety of pipes and fittings. The experiment consisted in the following: the

relationship between the head loss due to fluid friction and velocity for flow of water through a

smooth bore pipe for both laminar and turbulent flow, the head loss associated with flow of

water through standard fittings used in plumbing installation, and the relationship between fluid

friction coefficient and Reynolds number for flow of water through a roughened pipe. For the

completion of this experiment a wide variety of equipment was used. Our general equipment

used was the hydraulic bench, which allows us to take a specific volume of the fluid. For the

first part of the experiment (part A) two runs were necessary were made for both laminar and

turbulent flow. The head loss was taken and the Reynold’s number was to be calculated to

determine the behavior of the flow. For laminar flow the Reynolds number for the necessary two

runs are: 725.25 and 365.46. The velocities were of 0.0433m/s and 0.0209m/s respectively. The

head loss was of 0.014 mH20 for the first laminar flow and 0.020 mH2O for the second. The

values for the Reynold’s number in turbulent flow are 29,714.0 and 41,055.0, with velocities of

1.7030 m/s and 2.3545 m/s respectively. The head losses for turbulent flow were the following:

0.242 mH20 and 0.394 mH20. After these calculations were made in the smooth tube, a graph of

heat loss versus velocity was plotted to see how the fluid acts in turbulent and laminar flow. For

the second part of the experiment the K values for various pipe fitting were calculated. The

fitting used were the ball valve, the globe valve, the 30º elbow and the 45º elbow. These k

values can be found in table 5 of the Appendix, in which all experimental data for analyzing the

head loss due to pipe fittings is tabulated. The last part of the experiment was conduction with

the same principle as the first part but for a roughened pipe. The Reynold’s number for the first

two runs are: 429.10 and 345.25. The velocities were of 0.0246 m/s, 0.0198 m/s respectively.

The head loss was of 0.027 mH20 for the first laminar flow and 0.025 mH2O for the second. The

values for the Reynold’s number in turbulent flow are: 25,439.0 and 25,949.0. The velocities

were of 1.4593 m/s and 1.4884 m/s. The head losses for turbulent flow were the 0.577mH20 and

0.502 mH20. A graph was made in which the friction factor was plotted versus the log of

Reynolds.

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INDEX

Abstract....................................................................................................................................................... ii

Introduction.................................................................................................................................................1

Objectives....................................................................................................................................................2

Experiment A: Fluid Friction in a Smooth Bore Pipe................................................................................2

Experiment C: Head Loss Due to Pipe Fittings.........................................................................................2

Experiment D: Fluid Friction in a Roughened Pipe...................................................................................2

Theory.........................................................................................................................................................3

General Energy Balance:..........................................................................................................................3

The Forms of Energy............................................................................................................................4

Restrictions..........................................................................................................................................4

Bernoulli’s Equation:...............................................................................................................................6

Laminar Flow:......................................................................................................................................8

Turbulent flow:..................................................................................................................................14

Experiment A: Fluid Friction in a Smooth Bore Pipe..............................................................................16

Experiment C: Head Loss Due to Pipe Fitting.........................................................................................17

Experiment D: Fluid Friction in a Roughened Pipe.................................................................................20

Equipment.................................................................................................................................................22

Description............................................................................................................................................22

F1-10 Hydraulics Bench:........................................................................................................................23

Stopwatch:.............................................................................................................................................23

Schematic representation of the system:..............................................................................................24

Index sheet for C6 arrangement drawing..............................................................................................24

Procedure:.................................................................................................................................................27

Operational Procedures.........................................................................................................................27

Measurement of Flow Rates using the Volumetric Tank.......................................................................27

Operation of the Self-Bleeding manometers.........................................................................................28


Equipment Set-Up.............................................................................................................................29

Valve Settings....................................................................................................................................29

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Taking a Set of Results.......................................................................................................................29

Experiment C: Head Loss Due to Pipe Fittings.......................................................................................30

Equipment Set-Up.............................................................................................................................30



Equipment Set Up..............................................................................................................................30

Valve Settings....................................................................................................................................30


Results and Discussion...............................................................................................................................32


Experiment C: Head Loss Due to Pipe Fitting.........................................................................................34


Conclusion.................................................................................................................................................39

Fluid Friction in a Smooth Bore Pipe......................................................................................................39

Head Loss Due to Pipe Fitting................................................................................................................39

Fluid Friction in a Roughened Pipe........................................................................................................40

References.................................................................................................................................................41

Nomenclature............................................................................................................................................42

Appendix...................................................................................................................................................43

Calculus Example...................................................................................................................................43

Experiment A: Fluid Friction in a Smooth Bore Pipe..........................................................................43

Experiment C: Head Loss Due to Pipe Fitting.....................................................................................45

Experiment D: Fluid Friction in a Roughened Pipe.............................................................................45

Data.......................................................................................................................................................49

Experiment A: Fluid Friction in a Smooth Bore Pipe with 0.0175m diameter........................................49

Experiment C: Head loss due to pipe fittings.........................................................................................49


Security......................................................................................................................................................51

General Safety Rules..............................................................................................................................51

Safety in the use of equipment supplied by armfield............................................................................55

The COSHH Regulations.........................................................................................................................56

The Control of Substances Hazardous to Health Regulations (1988).................................................56

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Water-Borne Infections.....................................................................................................................57

Use of earth leakage circuit breaker as an electrical safety...................................................................58

Device................................................................................................................................................58

v

Introduction

The Fluid Friction Apparatus allows the study of flow, flow measurement techniques and losses

in a wide variety of pipes and fittings. It is designed to allow a detailed study of pressure drop as

a result of fluid friction, when an incompressible fluid flows through pipes, fittings, and flow

metering devices. Friction head losses in straight pipes of different sizes can be investigated with

a wide range of Reynolds number, covering laminar, transitional, and turbulent flow regimes. An

artificially roughened tube is also incorporated into the apparatus to demonstrate the departure

from typical smooth bore pipe characteristics.

Our study also focuses in the factors that cause a pressure loss in pipes, which includes pipe

length and diameter, flow velocity, a friction factor based on the roughness of the pipe and the

type of accessory, and the type of flow whether is turbulent or laminar. In this experiment we

will calculate the fluid friction head losses which occurs when water flows through smooth and

roughened pipes, a pipe with a 45o elbow accessory and a flow metering Pitot tube. The values

obtained in the fluid friction apparatus are compared with theoretical values calculated by the

equations studied in our fluid mechanics class. The pipes and accessories studied are equipment

of daily use in the modern industry including chemical plants. They are used to transport raw

materials from storage tanks to reactors and to transfer the product to different units of

operations.

Also the pipes play an important role in our daily life, transporting potable water for human

consumption or irrigation of soils used for agriculture. Pipes are used to transport fluids from

one place to another, the elbow facilitates the change in direction of the flow and the Pitot tube is

used to obtain the velocity of the fluid. Is important to known the pressure losses in pipes and

accessories caused by friction in order to design equipment (like pumps) that overcome this

losses in energy and changes in velocity.

1

Objectives

Experiment A: Fluid Friction in a Smooth Bore Pipe

Determine the relationship between the head loss due to fluid friction and velocity for

flow of water through a smooth bore pipe.

Experiment C: Head Loss Due to Pipe Fittings

Determine the head loss associated with flow of water through standard fittings used in

plumbing installations.

Experiment D: Fluid Friction in a Roughened Pipe

Determine the relationship between fluid friction coefficient and Reynolds number for

flow of water through a roughened pipe.

2

Theory

General Energy Balance:

The energy balance for steady, incompressible flow, called Bernoulli’s equation, is probably the

most useful single equation in fluid mechanics and it is used in this experiment. We begin with

the following equation.

Equation 1 [Steady flow, open system]

Where:

(PE)

E)

The energy balance expressed in Equation (1) applies to the changes from one point to the next,

along the direction of flow in any steady flow of homogeneous fluid. According to the First Law

of Thermodynamics, energy cannot be created or destroyed; the terms of creation and destruction

are zero, therefore:

Equation 2

3

If the material that constitutes the system is uniformed, has the same internal (U), potential (PE)

and kinetic energy (KE) though all the system:

Equation 3

4

The Forms of Energy

The following forms of energy are the ones being used for the general energy balance:

Internal Energy (U) = its increases depending on temperature.

Kinetic Energy (KE) = it’s the energy of a moving body.

Potential Energy (PE) = it depends on the position of a body relative to the bottom

in a gravitational field.

Restrictions

The following restrictions were taken under consideration for the general energy balance

(eq.1):

The magnetic, electrostatic and surface energy are neglected.

The content in the system is uniform.

The inlet and exit currents are uniform.

The gravities acceleration is constant.

The system has to have one exit and one inlet therefore it must be in steady state.

From these restrictions we can say that:

Equation 4

Equation 5

Therefore dividing by (dm) we have:

5

Equation 6

6

Regrouping the equation above (Equation 6):

Equation 7

It is important to remember that:

; therefore:

Equation 8

The pressure difference, P, in Equation (9) stands for Pout – Pin , etc. This equation is the

preliminary from Bernoulli’s equation. The term P/ stands for the injection-work, representing

the work required to inject a unit mass of fluid into or out of the system, or both. The potential

energy, gz, represents the potential energy of a unit mass of fluid above some arbitrary datum

plane. The V2/2 term shows the kinetic energy per unit mass of fluid. The dWn.f./dm term

represents the amount of work done on the fluid per unit mass of fluid passing through the

system. Heating due to friction will increase the internal energy of the system and the

temperature so it must be taken into account. The friction heating is caused by the interaction of

the moving fluid with the surroundings and does not depend on the quantity of heat transfer in or

out of the system. It is defined as:

Equation 9

Substituting the value for friction, expressed in Equation (9), in Equation (8) results in the following:

7

Equation 10

8

Bernoulli’s Equation:

Bernoulli's equation is one of the most important/useful equations in fluid mechanics. Grouping

common terms in Equation (10) changes to the final working form of Bernoulli’s Equation:

Equation 11

If friction heating is negative the flow is in opposite direction, for all real flows it is positive and

if F = 0 the flow is reversible. The classic-drop experiment to determine F is performed in an

apparatus like that shown in Figure 1.

Figure 1: Apparatus for the pressure drop experiment.

In this experiment volumetric flow rate is set with the flow regulating valve. Flow rate is

measured with a tank and a stop watch. At steady state pressure gauges P1 and P2 can be read

and record their difference from point one to point 2.

Regardless of what Newtonian liquid is flowing or what kind of pipe we use, a graph of -∆P/ ∆x

against Q is plotted and the result is always of the form shown in Figure 2. In this figure, if the

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volumetric flow rate, Q , is constant, then in the unstable region the flow will oscillate vertically

between the two curves of –dP/dx. If, instead, –dP/dx is fixed, then in the unstable region will

oscillate horizontally between two values of Q. In addition, at low flow rate ∆P/ ∆x is

proportional to volumetric flow rate, Q , to the 1.0 power where as high flow rate ∆P/∆x is

proportional to volumetric flow rate, Q , to a power that varies from 1.8 (for very smooth pipes)

to 2.0 ( for very rough pipes).

Figure 2: Typical pressure-drop curve for a specific fluid in a specific pipe.

Osborne Reynolds explained the strange shape of Figure 2 in an apparatus similar to that of

Figure 1 but made of glass, he arranged to introduce a liquid dye into the flowing stream at

various points. He found that, in the low flow rate region the dye he introduced formed a

smooth, thin, straight streak down the pipe as shown in Figure 3. This type of flow is called

laminar flow. He also found that in the high flow rate region, no matter where he introduced the

dye it rapidly dispersed throughout the entire pipe as shown in figure 4. This type of flow is now

called turbulent flow.

(a) (b)

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Figure 3: Schematic flow representations. (a) Laminar Flow, (b) Turbulent flow

Reynolds showed further than the region of irreproducible results between the regions of laminar

and of turbulent flow is the region of transition from the one type of flow to other, called

transition region. In the transition the flow can be laminar or turbulent. Reynolds also showed

that the transition from laminar to turbulent flow occurs when the dimensionless group called the

Reynold’s number(R) has a value of about 2000 according to the following equation:

Equation 12 [Reynolds number for flow in a circular pipe]

D is the pipe diameter, µ is the molecular viscosity (1.15x10 -3 Ns/m2 @ 150C of H2O), is the

density = 999 kg/m3 @150C for H2O, and v is the flow velocity.

Laminar Flow:

Laminar flow, sometimes known as streamline flow, occurs when a fluid flows in parallel layers,

with no disruption between the layers (Figure 5). Consider a steady laminar flow of an

incompressible Newtonian fluid in a horizontal circular tube or pipe as in Figure 6.

Figure 4: Laminar Flow Diagram

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Figure 5: Force-balance system in pipe flow.

Here, it is assumed that location one is well downstream from the place where the fluid enters the

tube. This analysis is not correct for the tube entrance. The flow is steady in all axial direction.

There is no acceleration in the x direction, so the sum of the forces acting in the x direction on

the rod-shaped element chosen must be zero. There is a pressure force acting on each end, equal

to the pressure times the cross sectional area of the end. These forces act in opposite direction;

there sum in the positive x direction is:

Equation 13

Equation 14

Equation 15

Since r1 = r2

Equation 16

Along the cylindrical surface there is a shear force resisting the flow, in opposite direction to the

pressure gradient, which is in the flow direction, its magnitude is

Equation 17

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Since the pressure force and shear force are the only forces acting in the x direction and there

sum is zero, these must be equal and opposite. Equating their sum to zero and solving for the

shear stress at r, we find

Equation 18 [Shear stress acting on the central rod]

The minus sign shows that τ acts in the minus x direction. This Equation applies to steady

laminar or turbulent flow of any kind of fluid in any circular pipe or tube. For Newtonian fluids

in laminar motion the shear stress is equal to the product of the viscosity and the velocity

gradient. Substituting in equation 18, we find

Equation 19

For steady laminar flow the pressure gradient (P1-P2)/∆x does not depend on radial position in the

pipe, so we may integrate this to:

Equation 20

Integration of leads to

Equation 21

To find the constant C, we assume V=0, r= r0

Equation 22

13

Equation 23

Substituting eq.23 in eEq.21 results in :

Equation 24

Rewriting eq.24 results in:

Equation 25

This equation says that for steady, laminar flow of Newtonian fluids in circular pipes:

1. The velocity is zero at the wall (r = r0)

2. The velocity is a maximum at the center of the pipe (r=0)

3. The magnitude of this maximum velocity is:

Equation 26

4. The pressure drop per unit length is independent of the fluid density and is proportional

to the first power of the local velocity and the first power of the viscosity.

5. The velocity-radius plot is a parabola (see Figure 6)

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Figure 6: Velocity distribution in steady, laminar flow of a Newtonian fluid in a circular pipe

To find the flow rate (Q) we multiply the velocity by the cross-sectional area to the perpendicular

flow. The velocity of the laminar flow described is not uniform, so we must integrate velocity

times area over the whole pipe cross section:

Equation 27

Equation 28

Substitution of eq. 26 and eq. 28 in eq. 27 leads to:

Equation 29

Equation 30

Equation 31

15

Where r0 is defined as:

Equation 32

Therefore substituting Equation 32 into Equation 31 we obtain the following equation known as

Poiseuille’s equation, which is for laminar fluid flow through a uniform straight pipe:

Equation 33

Equation 33 applies if the Reynolds number is less than 2000 and was first stated by Jean Louis

Poiseuille (1799–1869).

In order to calculate the friction (ℱ) we apply Bernoulli’s Equation from point 1 to point 2 (see

Figure 5). Analyzing Figure 5, we find no important change in height (z1=z2) or velocity (v1=v2)

from point 1 to point 2. There’s no work done (W=0) because the pipe walls are rigid.

Subjected to this analysis Bernoulli’s Equation can be written as:

Equation 34

Equation 35

Substituting Equation 35 in Equation 33:

Equation 36

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Equation 36 mathematically defines the ℱ in Bernoulli’s Equation on an horizontal flow in

which gravity plays no role. If the entire derivation is repeated for a vertical flow in a pipe, in

which the pressure is constant throughout, we find that:

Equation 37

Given that ΔP=ρgΔz, Equation 36 turns to the following:

Equation 38

Thus, for either horizontal or vertical laminar flow:

Equation 39

Turbulent flow:

Turbulent flow is a fluid regime characterized by chaotic, stochastic property changes. At some

critical velocity, the flow will become turbulent with the formation of eddies and chaotic motion

which do not contribute to the volume flow rate. This turbulence increases the resistance

dramatically so that large increases in pressure will be required to further increase the volume

flow rate.

17

Figure 7: Comparison diagram between laminar and turbulent flow. (a)Laminar flow, (b)Turbulent flow.

Since the velocity goes from zero at the pipe wall to the average velocity near the center, the

velocity gradient should be some function of Vavg/D. If we now assume that this is a linear

proportion and that the magnitude of the flow of mass back and forth across the surface of

constant y is proportional to the average velocity. The friction heating should be proportional to

the length of the pipe so we find that

Equation 40

A new factor is defined, the friction factor f, which is equal to half the proportionally constant in

and drop the average subscript on the velocity so that:

Equation 41

Rewriting leads to:

Equation 42

The friction factor f can be found in a graph (known friction factor plot or Moody diagram) as a

function of the Reynolds number and the relative roughness defined as:

18

Equation 43

The turbulent and transition region curves in factor friction plot or Moody Diagram can be

represented with very good accuracy by:

Equation 44

Where D is the pipe diameter and ε is the surface roughness and R is Reynold’s number.

Figure 8: Friction factor plot for circular pipes.

Figure 8 is currently the most commonly used friction factor plot prepared by Moody in pipes.

Moody also suggested the working values for the absolute roughness, shown in Table 1.

Table 1 Values of surface roughness for various materials to be used in figure 8

Surface roughness

ε, ft ε, in

Drawn tubing (brass, lead, glass, etc) 0.000005 0.00006

19

Commercial steel or wrought iron 0.00015 0.0018

Asphalted cast iron 0.0004 0.0048

Galvanizes iron 0.0005 0.006

Cast iron 0.00085 0.010

Wood stave 0.0006-0.003 0.0072-0.036

Concrete 0.001-0.01 0.012-0.12

Riveted steel 0.003-0.03 0.036-0.36

Figure 8 shows that, as the relative roughness becomes greater, the assumptions that went into

Equation (40) become better; f becomes a constant that is independent of diameter, velocity,

density, and fluid viscosity.


Graphs of h vs. u and log h vs. log u show the zones were the flow is laminar, turbulent, or in the

transition phase.

Figure 9: Graph of h plotted against u showing flow behavior in a smooth bore pipe.

20

Figure 10 Graph of log h vs. log u showing flow behavior in a smooth bore pipe.

Experiment C: Head Loss Due to Pipe Fitting

To calculate the head loss due to pipe fittings Bernoulli’s Equation must be applied:

Equation 45

The following assumptions were taken under consideration:

The flow is stationary

The velocity remains constant (v2=v1)

There is no work done on the system or the surroundings (W=0)

The change in height is negligible, h2=h1, (z was changed for h)

Subjected to these assumptions, Bernoulli’s Equation is reduced to:

Equation 46

Equation 47

21

As the fluid passes a fitting or accessory the friction can be put in the form of Equation 48.

Equation 48

Substituting Equation 45 in Equation 35 leads to:

Equation 49

Substituting P=ρgh in Equation 46 and rewriting it leads to:

Equation 50

A flow control valve is a pipe fitting which has an adjustable 'K' factor. The minimum value of

'K' and the relationship between stem movement and 'K' factor are important in selecting a valve

for an application. The 'K' values for various types of fittings are presented in Table 2 along with

their equivalent lengths.

Table 2: Equivalent lengths and K values for various kinds of fittings

Type of fitting Equivalent length, L/D, dimensionless

Constant, K, dimensionless

Globe valve, wide open 350 6.3

Angle valve, wide open 170 3.0

Gate valve, wide open 7 0.13

Check valve, swing type 110 2.0

90º standard elbow 32 0.74

45º standard elbow 15 0.3

90º long-radius elbow 20 0.46

Standard tee, flow-through run 20 0.4

Standard tee, flow-through branch 60 1.3

Coupling 2 0.04

22

Union 2 0.04

Head loss in a pipe fitting is proportional to the velocity head of the fluid flowing through the

fitting, setting h1 = 0 as reference rewriting eq. 47 leads to:

Equation 51

Where: K = fitting factor, v = mean velocity of water through the pipe (m/s), and g = 9.81

(acceleration due to gravity, m/s2).

Figure 11: Pipe fitting (45° elbow) to be used in experiment.


In a rough surface, like the one shown in Figure.13, turbulent flow is present, so turbulent flow

equations describe the movement inside a roughened pipe.

23

Figure 12: Fluid flow comparison through rough and smooth pipe

By empirical deduction it has been found that turbulent flow is proportional to the longitude and

the average velocity, and inversely proportional to the diameter of the pipe. Adding the friction

factor f , which is equal to half the proportionally constant in eq. 31 leads to:

Equation 52

Equation 53

Substituting P=ρgh in Equation 53 and rewriting leads to:

Equation 54

Where, ∆x= Length of pipe between tappings (m), D= internal diameter of the pipe (m), Vavg. =

mean velocity of water through the pipe (m/s), g = 9.81 (acceleration due to gravity, m/s2), f =

pipe friction coefficient (British), 4f = λ (American), and the roughness factor = k/ d where k is

the height of the sand grains.

24

Equipment

Description

All numerical reference relate to the ‘General Arrangement of Apparatus’. The test circuits are

mounted on a substantial laminate backboard, strengthened by a deep frame and carried on

tubular stands. There are six pipes arranged to provide facilities for testing the following:

Smooth bore pipes of various diameter (1), (2) and (4)

An artificially roughened pipe (3)

A 90 deg. bend (14)

A 90 deg. elbow (13)

A 45 deg. elbow (8)

A 45 deg. “Y” (9)

A 90 deg. “T” (15)

A sudden enlargement (6)

A sudden contraction (5)

A gate valve (10)

A globe valve (11)

A ball valve (7)

An in-line strainer (12)

A Venturi made of clear acrylic (17)

An orifice meter made of clear acrylic (18)

A pipe section made of clear acrylic with a Pitot static tube (16)

Short samples of each size test pipe (19) are provided loose so that the students can measure the

exact diameter and determine the nature of the internal finish. The ratio of the diameter of the

pipe to the distance of the pressure tappings from the ends of each pipe has been selected to

minimize end and entry effects. A system of isolating valves (V4) is provided whereby the pipe

to be tested can be selected without disconnecting or draining the system. The arrangement

allows tests to be conducted on parallel pipe configurations.

26

An all GRP floor standing service module incorporates a sump tank (23) and a volumetric flow

measuring tank (22). Rapid and accurate flow measurement is thus possible over the full

working range of the apparatus. The level rise in the measuring tank is determined by an

independent sight gauge (25). A small polypropylene measuring cylinder of 250ml capacity (28)

is supplied for measuring the flow rate under laminar conditions (very low flows).

Ported manometer connection valves (V7) ensure rapid bleeding of all interconnecting pipe

work.

The equipment includes a submersible, motor-driven water pump (24) and the necessary

interconnecting pipe work to make the rig fully self-contained. A push button starter (26) is

fitted, the starter incorporating overload and no-volt protection. An RCCB (ELCB) is also

incorporated.

Each pressure tapping is fitted with a quick connection facility. Probe attachments with an

adequate quantity of translucent polythene tubing are provided, so that any pair of pressure

tapping can be rapidly connected to one of the two manometers supplied. These are a mercury

manometer (20) and a pressurized water manometer (21).

NOTE: To connect a test probe to a pressure point, simply push the tip of the test probe

into the pressure point until it latches. To disconnect a test probe from a pressure

point, pressure point, press the metal clip of the side of the pressure point to

release the test probe. Both test probe and pressure point will seal to prevent loss

of water.

F1-10 Hydraulics Bench:

The F1-10 Hydraulics Bench, shown in Figure (8) allows us to measure flow by timed volume

collection. It also provides the necessary facilities to support a comprehensive range of

hydraulic models each of which is designed to demonstrate a particular aspect of hydraulic

theory.

Stopwatch:

A stopwatch allows students to determine the rate of a flow of water.

27

Schematic representation of the system:

Figure 13: Schematic diagram of The Friction Apparatus

Index sheet for C6 arrangement drawing

V1 SUMP TANK DRAIN VALVE

V2 INLET FLOW CONTROL VALVE

V3 AIR BLEED VALVE

V4 INSOLATING VALVES

V5 OUTLET FLOW CONTROL VALVE (FINE)

V6 OUTLET FLOW CONTROL VALVE (COARSE)

V7 MANOMETER VALVES

1 6mm SMOOTH BORE TEST PIPE

2 10mm SMOOTH BORE TEST PIPE

3 ARTIFICIALLY ROUGHENED TEST PIPE

28

4 17.5mm SMOOTH BORE TEST PIPE

5 SUDDEN CONTRACTION

6 SUDDEN ENLARGEMENT

7 BALL VALVE

8 45 deg. ELBOW

9 45 deg. “Y” JUNCTION

10 GATE VALVE

11 GLOBE VALVE

12 IN-LINE STRAINER

13 90 deg. ELBOW

14 90 deg. BEND

15 90 deg. “T” JUNCTION

16 PITOT STATIC TUBE

17 VENTURI METER

18 ORIFICE METER

19 TEST PIPE SAMPLE

20 1m MERCURY MANOMETER

21 1m PRESSURISED WATER MANOMETER

22 VOLUMETRIC MEASURING TANK

23 SUMP TANK

24 SERVICE PUMP

29

25 SIGHT TUBE

26 PUMP START/STOP

27 SIGHT GAUGE SECURING SCREWS

28 MEASURING CYLINDER (Loose)

29 DUMP VALVE

30

Procedure:

Operational Procedures

Flow rates through the apparatus may be adjusted by operation of outlet floe control

valve (V6).

Simultaneous operation of inlet flow control valve (V2) will permit adjustment of the

static pressure in the apparatus together with the flow rate.

Fine outlet control valve (V5) will permit accurate control at very low flow rates.

Suitable selection and operation of these control valves will enable tests to be performed

at different, independent combinations of flow rate and system static pressure.

Measurement of Flow Rates using the Volumetric Tank

The service module incorporates a molded volumetric measuring tank (22) which is

stepped to accommodate low or high flow rates.

A stilling baffle is incorporated to reduce turbulence.

A remote sight gauge (25), consisting of a sight tube and scale, is connected to a tapping

in the base of the tank and gives an instantaneous indication of water level.

The scale is divided into two zones corresponding to the volume above and below the

step in the tank.

A dump valve in the base of the volumetric tank is operated by a remote actuator (29).

In operation, the volumetric tank is emptied by lifting the dump valve, allowing the

entrained water to return to the stump (23).

When test conditions have stabilized, the dump valve is lowered, entraining the water in

the tank.

Timings are taken as the water level rises in the tank.

Low flow rates are monitored on the lower portion of the scale corresponding to the small

volume beneath the step.

Larger flow rates are monitored on the upper scale corresponding to the main tank.

Before operation, the position of the scale relative to the tank should be adjusted as

described in the commissioning section.

31

When extremely small volumetric flow rates are to be measured, the measuring cylinder

(28) should be used rather than the volumetric tank.

When using the measuring cylinder, diversion of the flow to and from the cylinder should

be synchronized as closely as possible with the starting and stopping of a watch.

Do not attempt to use a definite time or a definite volume.

Operation of the Self-Bleeding manometers

Both pressurized water manometer installed on the apparatus are fitted with quick

connection test probes and self-bleeding pipe work.

Each pressure point on the apparatus is fitted with a self-sealing connection.

To connect a test probe to a pressure point, simply push the tip of the test probe into the

pressures point until it latches.

To disconnect a test probe from a pressure point, press the metal clip of the side of the

pressure point to release the test probe.

Both test probe and pressure point will seal to prevent loss of water.

Each test probe is connected to the limb of a manometer via a vented ball valve which is

situated over the volumetric tank.

In operation, the connecting valves are set to the 90o position and the test probes screwed

onto the required test points.

Pressure in the test pipe, drives fluid along the flexible connecting pipe pushing air

bubbles to the valve where the mixture of air and water is ejected into the volumetric tank

via the vent in the body.

In this condition the valve connection to the manometer remains sealed keeping the

manometer fully primed.

When all air bubbles have been expelled at the vent, the valve is turned through 90o to the

live position connecting the test point directly to the manometer.

Prior to removal of the test probe, the valve is returned to the 90o position to prevent loss

of water from the manometer.

Using this procedure, the manometers once primed will remain free from air bubbles

ensuring accuracy in readings.

The pressurized water manometer incorporates a Schrader valve which is connected to

the top manifold.

32

This permits the levels in the limbs to be adjusted for measurement of small differential

pressures at various static pressures.

Then hand supplied will be required to effect reduction of levels at high static pressures.

Alternatively a foot pump (not supplied) may be used.


Equipment Set-Up

Refer to the diagram “General Arrangement of Apparatus”.

Valve Settings

Close V1, 10, V4 in test pipe 3

Open V2

Open V 4 in test pipe 1, V 4 in test pipe 2 or 7 in test pipe 4 as required.

Open A and B or C and D after connecting probes to tappings.

Taking a Set of Results

Prime the pipe network with water.

Open and close the appropriate valves to obtain flow of water through the required test

pipe.

Measure flow rates using the volumetric tank in conjunction with flow control valve V6.

For small flow rates use the measuring cylinder in conjunction with flow control valve

V5 (V6 closed).

Measure head loss between tappings using the Hg manometer or pressurized water

manometer as appropriate.

Obtain readings on test pipe 4.

Experiment C: Head Loss Due to Pipe Fittings

Equipment Set-Up

Refer to the diagram “General Arrangement of Apparatus”.

33


Prime the network with water.

Open and close the appropriate valves to obtain flow of water through the ball valve.


Measure differential head between tappings on each fitting using the pressurized water

manometer.

Measure differential head between tappings on test valves using the pressurized water

manometer and mercury manometer as appropriate for different valve settings (open to

dosed).

Repeat this procedure for the following fittings: the ball valve, the globe valve, the 30º

elbow and the 45º elbow.


Equipment Set Up

Refer to the diagram "General Arrangement of Apparatus".

Valve Settings

Close V1, 10

Close V4 in test pipe 1, V 4 in test pipe 2 and 7 in test pipe 4.

Open V2

Open V 4 in test pipe 3 (roughened)

Open A and B or C and D after connecting probes to tappings.


Prime the pipe network with water.

Open and close the appropriate valves to obtain flow of water through the roughened

pipe.

34


For small flow rates use the measuring cylinder in conjunction with flow control valve

V5 (V6 dosed).

Measure head loss between the tappings using the pressurized water manometer as

appropriate.

Estimate the roughness factor k/ d.

Obtain readings on test pipe 3

35

Results and Discussion


Part A of the experiment consisted in determining the relationship of the head loss due to friction

in both, laminar (Re<2000) and turbulent (Re>4000) flow. Two runs were necessary for each

type of flow, for which the head loss was taken and the Reynold’s number was to be calculated

to determine the type behavior, laminar or turbulent. Using the fluid friction apparatus it’s easier

to apply a relatively large velocity and to measure a large flow rate, therefore the turbulent flow

was easier to achieve than the laminar flow. To achieve an acceptable laminar flow the flow

rate, Q, had to be greatly reduced.

At the beginning, the first values of the Reynold’s number calculated, for each different type of

flow rate (Q), were all over 4000 (Re>4000) meaning that the flow remained turbulent. To

achieve the laminar flow, the flow rate, Q, was successfully reduced and was measured using a

test tube. The Reynolds numbers for the two runs in laminar flow are: 725.25 and 365.46. The

velocities were of 0.0433m/s and 0.0209m/s respectively. The head loss was of 0.014 mH20 for

the first laminar flow and 0.020 mH2O for the second. The values for the Reynold’s number in

turbulent flow are 29,714.0 and 41,055.0, with velocities of 1.7030 m/s and 2.3545 m/s

respectively. The head losses for turbulent flow were the following: 0.242 mH20 and 0.394

mH20. From these results we can see that the head loss for turbulent flow is bigger than that of a

laminar flow in a smooth pipe.

The linear regression of a h vs. u graph is plotted in Figure 14, where h is the head loss and u is

the velocity. In this graph we can see that the laminar flow for the 0.0175m smooth bore pipe is

a straight line but when the flow is turbulent the is a slight curvature. Also the lineal regression

of a log h vs. log u graph is plotted, where h is the head loss and u is the velocity (see Figure 15).

The behavior in Figure 15 does not compare to its theoretical graph presented in the theory. This

36

difference is because of experimental errors during the procedure and handling of the equipment.

One of the possibilities is that there was air in the pipes we didn’t notice. The water manometer

lacks accuracy and the water inside it wasn’t clean, there were several noticeable particles.

Water was also coming out of the threads, which can also cause experimental errors. Personal

errors are another source due to poor handling of the equipment or wrong calculations.

Figure 14: Graph showing h(m) vs u(m/s) behavior for a smooth bore pipe.

Figure 15: Graph showing log h vs log u behavior for a smooth bore pipe.

37


The fitting factor (K) was calculated as the slope from the lineal regression of a ∆h vs. v2/2g

graph, where ∆h is the head loss, v is the velocity and g is the acceleration due to gravity. The

fittings used were the following: ball valve, 30º elbow, 45º elbow, and globe valve. The

theoretical value was calculated with the following equation:

The values calculated for the k values of the various pipe fittings in laminar flow are the

following:

Table 3: Values of the fitting factor, k, for various pipe fittings in both laminar and turbulent flow.

Fitting factor k theoretical

Fitting factor k experimental

Difference %

Globe valve 0.6004 0.5625 6.51

Ball valve (open) 0.7621 0.493 42.88

Ball valve

(semi open)

0.9006 0.6457 32.96

30°elbow 0.6090 0.599 1.65

45°elbow 0.4754 0.550 14.55

For a globe valve got a fitting factor (K) of 0.5625, a difference of 6.51%. In this way, one can

notice a good approximation to the theoretical value (0.6004). In an open ball valve fitting

yielded a factor (k) of 0.4930 and a difference value of 42.88% while in a semi-open ball valve

was obtained an experimental value of 0.6457 for a 32.96% difference. This compared with a

theoretical value of 0.7621 and 0.9006, demonstrating a difference much larger than the globe

valve.

In a 30-degree elbow fitting yielded a factor of 0599 and compared with theoretical value of

38

0.6090, remained a difference of 1.65%. While for an elbow of 45 degrees was fitting factor of

0.550 and the difference was 14.55%, which compared with its theoretical value of 0.4754.

Demonstrating a lower value approximation to 30-degree elbow.

Figure 16: Graph showing h (mH2O) plotted versus u2/2g behavior for a globe valve in laminar and turbulent flow.

Figure 17: Graph showing h (mH2O) plotted versus u2/2g behavior for a 30º elbow in laminar and turbulent flow.

39

Figure 18: Graph showing h (mH2O) plotted versus u2/2g behavior for a 45º elbow in laminar and turbulent flow

Figure 19: Graph showing h (mH2O) plotted versus u2/2g behavior for a ball valve wide open in laminar and turbulent flow

40

Figure 20: Graph showing h (mH2O) plotted versus u2/2g behavior for a semi open ball valve in laminar and turbulent flow


Part D of the experiment consisted in determining the relationship of the head loss due to friction

in both, laminar (Re<2000) and turbulent (Re>4000) flow for a roughened pipe. Two runs were

necessary for each type of flow, for which the Reynold’s number was to be calculated to

determine the type behavior, laminar or turbulent. Using the friction apparatus it’s easier to

apply a relatively large velocity and to measure a large flow rate, therefore the turbulent flow

was easier to achieve than the laminar flow. To achieve an acceptable laminar flow the flow

rate, Q, had to be greatly reduced. The Reynold’s number for the first two runs are: 429.10 and

345.25. Given that the Reynold’s numbers are smaller than 2000 (Re<2000) the flow is laminar.

This laminar flow was achieved reducing the flow rate, Q, which was measured using a test tube.

The velocities were of 0.0246 m/s, 0.0198 m/s respectively. The head loss was of 0.027 mH 20

for the first laminar flow and 0.025 mH2O for the second. The values for the Reynold’s number

in turbulent flow are: 25,439.0 and 25,949.0. The velocities were of 1.4593 m/s and 1.4884 m/s.

The head losses for turbulent flow were the 0.577mH20 and 0.502 mH20. From these results we

can see that the head loss for turbulent flow is bigger than that of a laminar flow in a roughened

pipe. In Figure 21 the relation between the Reynold’s number and the friction coefficient for a

roughened pipe.

41

Figure 21: Experimental data of λ=4f plotted against Re in logarithm scale graphic showing the relation between the pipe friction factor and Reynolds’s Number of roughened pipe

Figure 21 does not compare to the graph stipulated by the theory for this part of the experiment.

The sources of the experimental errors are the following: there might have been air in the pipes

we didn’t notice. The water manometer lacked accuracy and the water inside it wasn’t clean,

there were several noticeable particles. Water was also coming out of the threads, which can

also cause experimental errors. Personal errors are another source due to poor handling of the

equipment or wrong calculations.

42

Conclusion

Fluid Friction in a Smooth Bore Pipe

The Reynolds numbers for the two runs in laminar flow are: 725.25 and 365.46. The velocities

were of 0.0433m/s and 0.0209m/s respectively. The head loss was of 0.014 mH20 for the first

laminar flow and 0.020 mH2O for the second. The values for the Reynold’s number in turbulent

flow are 29,714.0 and 41,055.0, with velocities of 1.7030 m/s and 2.3545 m/s respectively. The

head losses for turbulent flow were the following: 0.242 mH20 and 0.394 mH20.

The linear regression of h vs. u graph is plotted in Figure 14, where h is the head loss and u is the

velocity. In this graph we can see that the laminar flow for the 0.0175m smooth bore pipe is a

straight line but when the flow is turbulent the is a slight curvature. From this graph we can

conclude that at small velocities the flow is laminar and at high velocities the flow is turbulent.

The previous statement validated the theory established for laminar and turbulent flow in a

smooth bore pipe. The linear regression of a log h vs. log u shown in Figure 15 does not

compare to its theoretical graph presented in the theory. This difference is because of

experimental errors during the procedure and handling of the equipment. One of the possibilities

is that there was air in the pipes we didn’t notice. The water manometer lacks accuracy and the

water inside it wasn’t clean, there were several noticeable particles. Water was also coming out

of the threads, which can also cause experimental errors. Personal errors are another source due

to poor handling of the equipment or wrong calculations.

Head Loss Due to Pipe Fitting

The fitting factor (K) in a globe valve was calculated as the slope from the lineal regression of a

∆h vs. v2/2g graph, as seen in the results calculated the value of fitting factor (K), is 0.5625 and a

percent (%) difference of 6.51%, which means the value calculated agree with the theoretical

value (0.6004). In an open ball valve there was a difference of 42.98% in its fall in fitting factor,

which makes seeing the change from laminar flow and turbulent flow much more precise in the

chart. While for the same semi open the valve fitting factor was a 32.96% difference and graphic

43

contrast decreases with the valve open. Demonstrating a higher pressure drop in the semi-open

ball valve. The 30 degree elbow fitting factor is a difference of 1.65% which clearly demonstrates the

transition period is increasing so it counts down to a turbulent flow. While for the 45-degree elbow

fitting factor (k) is 14.55% and has a very similar graph but with a fall in pressure much faster

shown in the chart. Some of the errors that can make the difference values are large, may arise

due to air in the sleeves, a visual readout of the pressure drop, some error when working on the

valve or system, accuracy by looking at the stopwatch , among other small errors that can arise

while and performed an experiment.

1. Fluid Friction in a Roughened PipeThe Reynold’s number for the first two runs are: 429.10 and 345.25. Given thess Reynold’s numbers are smaller than 2000 (Re<2000) the flow is laminar. The velocities were of 0.0246 m/s, 0.0198 m/s respectively. The head loss was of 0.027 mH20 for the first laminar flow and 0.025 mH2O for the second. The values for the Reynold’s number in turbulent flow are: 25,439.0 and 25,949.0. The velocities were of 1.4593 m/s and 1.4884 m/s. The head losses for turbulent flow were the 0.577mH20 and 0.502 mH20. The relation between the Reynold’s number and the friction coefficient for a roughened pipe was plotted in Figure 21, which does not compare to the graph stipulated by the theory for this part of the experiment. There were various sources for experimental errors which are explained in the results and discussion.

44

ReferencesDe Nevers, N. (2005), Fluid Mechanics for Chemical Engineers, 3rd

Edition, Mc Graw-Hill company, International Edition, USA, ISBN: 007-

123824-7

Armfield Ltd (August 2001), Issue 15, Instruction Manual: Fluid Friction Apparatus

McGraw Hills. (1997). Chapter 6:Fluid Friction in Steady, One Dimensional Flow. In N.

D. Neveres, Fluid Mechanics for Chemical Engineers (pp. 174-194). Philadelphia, United

State: Elizabeth A. Jones.

45

Nomenclature

Column

Heading

Units Nom. Type Description

Orifice

Diameter

M d Measured Orifice Diameter. The diameter is entered

in mm. Convert to meters for the

calculation.

Area of

Orifice

m2 A0 Calculated Orifice area, calculated from the orifice

diameter.

Area of

Reservoir

m2 AR Given Surface area of the reservoir including area

of constant head tank.

Head M h Measured Head in reservoir at time t. The head is

entered in mm. Convert to meter for the

calculation.

Head at

Start

M h1 Measured Head in reservoir at t = 0. The heat is

entered in mm. Convert to meters for the

calculation.

Time S t Measured Time since start of the run.

(h)0.5 Calculated Allows plotting of a straight line

relationship between coefficient of

discharge, Cd, and the head loss.

Slope S CalculatedSlope of t Vs. for each point.

Discharge

Coefficient

Cd

Cd Calculated

46

Appendix

Calculus Example


Examples for Run #1 in a smooth bore pipe with laminar flow

1. Conversion from liters (mL) to cubic meters ( )

2. Calculation of flow rate (Q): 2

3. Calculation of velocity (u):

4. Conversion from millimeters (mm) to meters (m)

5. Calculation of velocity logarithm (log u):

6. Calculation of head loss logarithm (log h):

47

7. Calculating the Reynolds Number:

Examples for Run #1 in a smooth bore pipe with turbulent flow

1. Conversion from liters (L) to cubic meters ( )

2. Calculation of average time (s):

3. Calculation of flow rate (Q):



6. Calculation of velocity logarithm (log u):

48

7. Calculation of head loss logarithm (log h):



Examples for Run #1 in pipe fittings with laminar flow

1. Conversion from millimeters (mL) to cubic meters ( )



4. Calculation of velocity head (hu):


49

6. Calculation of the or slope or experimental Fitting Factor (K) :

The slope of the linear regression vs. graph is calculated using computational

program Excel.

7. Calculation of the theoretical Fitting Factor (K):

8. Calculation of Percent(%) Difference:

%diff= = x 100 = 6.51%



Examples for Run #1 in a roughened pipe with laminar flow

1. Conversion from liters (mL) to cubic meters ( )


50




1. Calculation of friction factor ( f):

2. Calculation of Reynold’s logarithm (log Re):

3. λ=4f (Value to be plotted versus log Re)

Examples for Run #1 in a roughened pipe with turbulent flow

4. Conversion from liters (L) to cubic meters ( )

51

5. Calculation of average time (s):





10. Calculation of friction factor ( f):

11. Calculation of Reynold’s logarithm (log Re):

12. λ=4f (Value to be plotted versus log Re)

52

Data

Experiment A: Fluid Friction in a Smooth Bore Pipe with 0.0175m diameter

Table 4: Experimental data for fluid friction in a smooth bore pipe with 0.0175 in diameter

Volume(m3)

Time (s)

Flow rate Q (m3/s)

Diameter (m)

Velocity u (m/s)

Head loss h (mH2O)

Log u Log h Re #

2.5 x 10-5 2.40 1.04 x 10-5 0.0175 0.0433 0.014 -1.3635 -1.8539 755.253.1 x 10-5 6.15 5.04 x 10-6 0.0175 0.0209 0.020 -1.6786 -1.6990 365.465.0 x 10-6 12.25 4.09 x 10-4 0.0175 1.7030 0.242 0.2312 2.3838 297145.0 x 10-6 8.83 5.66 x 10-4 0.0175 2.3545 0.394 0.3719 -0.0404 41055

Experiment C: Head loss due to pipe fittings

Table 5: Experimental data taken on various pipe fittings in both laminar and turbulent flow.

Pipe Volume(m3)

Time (s)

Flow rate Q (m3/s)

Velocity u (m/s)

Fitting factor

k

u2/2g Head loss h

(mH2O)

Re #

Run #1 Laminar FlowGlobe valve 2.5 x 10-5 2.40 1.04 x 10-5 0.0433 0.601 0.00096 0.033 755.49Ball valve

(open)2.5 x 10-5 2.40 1.04 x 10-5 0.0433 0.763 0.00096 0.039 755.49

30°elbow 2.5 x 10-5 2.40 1.04 x 10-5 0.0433 1.021 0.00096 0.044 755.4945°elbow 2.5 x 10-5 2.40 1.04 x 10-5 0.0433 0.833 0.00096 0.036 755.49

Run #2 Laminar FlowGlobe valve 3.1 x 10-5 6.15 5.04 x 10-6 0.02096 0.811 0.00002 0.017 365.46Ball valve

(open)3.1 x 10-5 6.15 5.04 x 10-6 0.02096 0.716 0.00002 0.015 365.46

30°elbow 3.1 x 10-5 6.15 5.04 x 10-6 0.02096 0.763 0.00002 0.016 365.4645°elbow 3.1 x 10-5 6.15 5.04 x 10-6 0.02096 0.763 0.00002 0.016 365.46

Run #1 Turbulent FlowGlobe valve 3.1 x 10-5 6.15 5.04 x 10-6 0.02096 0.525 0.00002 0.011 365.46Ball valve

(open)5.0 x 10-6 13.97 3.6 x 10-4 1.4884 0.036 0.11291 0.055 2.54 x 104

Ball valve(semi-open)

5.0 x 10-6 13.97 3.6 x 10-4 1.4884 0.001 0.11291 0.002 2.54 x 104

30°elbow 5.0 x 10-6 13.97 3.6 x 10-4 1.4884 0.034 0.11291 0.051 2.54 x 104

45°elbow 5.0 x 10-6 13.97 3.6 x 10-4 1.4884 0.054 0.11291 0.081 2.54 x 104

53


Table 6: Experimental data for fluid friction in a roughened pipe with 0.0175 in diameter

Volume(m3)

Time (s)

Flow rate Q (m3/s)

Diameter (m)

Velocity u (m/s)

Head loss h

(mH2O)

Experimental

friction factor f

λ=4f Re # Log Re

3.0 x 10-5 6.30 4.76 x 10-6 0.0175 0.0198 0.0025 0.54740 2.18960 345.25 2.53812.9 x 10-5 4.90 5.92 x 10-6 0.0175 0.0246 0.0027 0.32830 1.31320 429.10 2.63245.0 x 10-6 14.25 3.51 x 10-4 0.0175 1.4593 0.5770 0.02326 0.09304 25439 4.40555.0 x 10-6 13.97 3.58 x 10-4 0.0175 1.4884 0.5020 0.01950 0.07800 25949 4.4141

54

Security

General Safety Rules

1. Follow Relevant Instructions

a. Before attempting to install, commission or operate equipment, all relevant

suppliers’/manufacturers’ instructions and local regulations should be understood

and implemented.

b. It is irresponsible and dangerous to misuse equipment or ignore instructions,

regulations or warnings.

c. Do not exceed specified maximum operating conditions (e.g. temperature, pressure,

speed, etc).

2. Installation

a. Use lifting tackle where possible to install equipment. Where manual lifting is

necessary beware of stained backs and crushed toes. Get help form an assistant if

necessary. Wear safety shoes where appropriate.

b. Extreme care should be exercised to avoid damage to the equipment during

handling and unpacking. When using slings to lift equipment, ensure that the slings

are attached to structural framework and do not foul adjacent pipework, glassware

etc. When using the fork lift trucks, position the forks beneath structural framework

ensuring that the forks do not foul adjacent pipework, glassware etc. Damage may

go unseen during commissioning creating a potential hazard to subsequent

operators.

c. Where special foundations are required follow the instructions provided and do not

improvise. Locate heavy equipment at low level.

d. Equipment involving inflammable or corrosive liquids should be sited in a

containment area or bund with a capacity 50% greater than the maximum

equipment contents.

55

e. Ensure that all services are compatible with the equipment and that independent

isolators are always provided and labeled. Use reliable connections in all instances,

do not improvise.

f. Ensure that all equipment is reliably earthed and connected to an electrical supply at

the correct voltage. The electrical supply must incorporate a Residual Current

Device (TCD) (alternatively called an Earth Leakage Circuit Breaker – ELCB) to

protect the operator from severe electric shock in the event of misuse or accident.

g. Potential hazards should always be the first consideration when deciding on a

suitable location for equipment. Leave sufficient space between equipment and

between walls and equipment.

3. Commissioning

a. Ensure that the equipment is commissioned and checked by a competent member of

staff before permitting students to operate it.

4. Operation

a. Ensure that students are fully aware of the potential hazards when operating

equipment.

b. Students should be supervised by a competent member of staff at all times when in

the laboratory. No one should operate equipment alone. Do not leave equipment

running unattended.

c. Do not allow students to derive their own experimental procedure unless they are

competent to do so.

d. Serious injury can result for touching apparently stationary equipment when using a

stroboscope to freeze rotary motion.

5. Maintenance

a. Badly maintained equipment is a potential hazard. Ensure that a component

member of staff is responsible for organizing maintenance and repairs on a planned

basis.

b. Do not permit faulty equipment to be operated. Ensure repairs are carried out

competently and checked before students are permitted to operate the equipment.

6. Using electricity

56

a. At least one each month, check that ELCB’s (RCCB’s) are operating correctly by

pressing the TEST button. The circuit breaker must trip when the button is pressed

(failure the trip means that the operate is not protected and a a repair must be

affected by a component electrician before the equipment or electrical supply is

used).

b. Electricity is the commonest cause of accident in the laboratory. Ensure that all

members of staff and student respect it.

c. Ensure that the electrical supply has been disconnected from the equipment before

attempting repairs or adjustments.

d. Water and electricity are not compatible and can cause serious injury if they come

into contact. Never operate portable electric appliances adjacent to equipment

involving water unless some form of constraint or barrier is incorporate to prevent

accidental contact.

e. Always disconnect equipment from the electrical supply when not in use.

7. Avoiding fires or explosion

a. Ensure that the laboratory is provided with adequate fire extinguishers appropriate

to the potential hazard.

b. Where inflammable liquids are used, smoking must be forbidden. Notices should be

displayed to enforce this.

c. Beware since fine powders or dust can spontaneously ignite under certain

conditions. Empty vessels having contained inflammable liquids can contain vapor

and explode if ignited.

d. Bulk quantities of inflammable liquids should be stored outside the laboratory in

accordance with local regulations.

e. Storage tanks on equipment should not overfill. All spillages should be immediately

cleaned up, carefully disposing of any contaminated cloths etc. Beware of slippery

floors.

f. When liquids giving off inflammable vapors are handled in the laboratory, the area

should be ventilated by an ex-proof extraction system. Vents on the equipment

should be connected to the extraction system.

57

g. Student should not be allowed to prepare mixtures to analysis or other purpose

without competent supervision.

8. Handling poisons, corrosive or toxic materials

a. Certain liquids essential to the operation of equipment, for example mercury, are

poisonous or can give off poisonous vapors. Wear appropriate protective clothing

when handling such substances. Clean up any spillage immediately and ventilate

areas thoroughly using extraction equipment. Beware of slippery floors.

b. Do not allow food to be brought into or consumed in the laboratory. Never use

chemical beakers as drinking vessels.

c. Where poisonous vapors are involved, smoking must be forbidden. Notices should

be displayed to enforce this.

d. Poisons and very toxic materials must be kept in a locked cupboard or store and

checked regularly. Use of such substances should be supervised.

e. When diluting concentrated acids and alkalis, the acid or alkali should be added

slowly to water while stirring. The reverse should never be attempted.

9. Avoiding cuts and burns

a. Take care when handling sharp edged components. Do not exert undue force on

glass or fragile items.

b. Hot surfaces cannot, in most cases, be totally shielded and can produce severe burns

even when not ‘visible hot’. Use common sense and think which parts of the

equipment are likely to be hot.

10. Eye protection

a. Goggles must be worn whenever there is a risk to the eyes. Risk may arise from

powders, liquid splashes, vapors or splinters. Beware of debris from fast moving air

streams. Alkaline solutions are particularly dangerous to the eyes.

b. Never look directly at a strong source of light such as a laser or Xenon arc lamp.

Ensure that equipment using such a source is positioned so that passers-by cannot

accidentally view the source of reflected ray.

c. Facilities for eye irrigation should always be available.

11. Ear Protection

a. Ear protectors must be worn when operating noisy equipment.

58

12. Clothing

a. Suitable clothing should be worn in the laboratory. Loose garments can cause

serious injury if caught in rotating machinery. Ties, rings on fingers etc. should be

removed in these situations.

b. Additional protective clothing should be available for all members of staff and

students as appropriate.

13. Guards and safety devices

a. Guards and safety devices are installed on equipment to protect the operator. The

equipment must not be operated with such devices removed.

b. Safety valves, cut-outs or other safety devices will have been set to protect the

equipment. Interference with these devices may create a potential hazard.

c. It is not possible to guard the operator against all contingencies. Use common sense

to at all times when in the laboratory.

d. Before starting a rotating machine, make sure staff are aware how to stop it in an

emergency.

e. Ensure that speed control devices are always set at zero before starting equipment.

14. First aid

a. If an accident does occur in the laboratory it is essential that first aid equipment is

available and that the supervisor knows how to use it.

b. A notice giving details of a proficient first-aider should be prominently displayed.

c. A ‘short list’ of the antidotes for the chemicals used in a particular laboratory

should be prominently displayed.

Safety in the use of equipment supplied by armfield

Before proceeding to install commission or operate the equipment described in this instruction

manual we wish to alert you to potential hazards so that they may be avoided.

Although designed for safe operation, any laboratory equipment may involve procedures which

are potentially hazardous. The major potential hazards associated with this particular equipment

are listed below.

INJURY THROUGH MISUSE

INJURY FROM ELECTRIC SHOCK

59

POISONING FROM TOXIC MATERIALS (E.G. MERCURY)

INJURY FROM INCORRECT HANDLING

RISK OF INFECTION DUE TO LACK OF CLEANLINESS

Accidents can be avoided provided that equipment is regularly maintained and staff and students

are made aware of potential hazards. A list of general safety rules is included in this manual, to

assist staff and students in this regard. The list is not intended to be fully comprehensive but for

guidance only

The COSHH Regulations

The Control of Substances Hazardous to Health Regulations (1988)

The COSHH regulations impose a duty on employers to protect employees and others from

substances used at work which may be hazardous to heath. The regulations require you to make

an assessment of all operations which are liable to expose any person to hazardous solids,

liquids, dusts, vapors, gases or micro-organisms. You are also required to introduce suitable

procedures for handling these substances and keep appropriate records.

Since the equipment supplies by Armfield Limited may involve the use of substances which can

be hazardous (for example, cleaning fluids used for maintenance of chemicals used for particular

demonstrations) it is essential that the laboratory supervisor or some other person in authority is

responsible for implementing the COSHH regulations.

Parts of the above regulations are to ensure that the relevant Health and Safety Data Sheet are

available for all hazardous substances used in the laboratory. Any person using a hazardous

substance must be informed of the following:

Physical data about the substance

Any hazard from fire of explosion

Any hazard to health

Appropriate Fist Aid treatment

Any hazard form reaction with the other substances

How to clean/dispose of spillage

Appropriate protective measures

Appropriate storage and handling

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Although these regulations may not be applicable in your country, it is strongly recommended

that a similar approach is adopted for the protection of the students operating the equipment.

Local regulations must also be considered.

Water-Borne Infections

The equipment described in this instruction manual involves the use of water in which under

certain conditions can create a health hazard due to infection by harmful microorganisms.

For example, the microscopic bacterium called Legionella pneumophila will feed on any scale,

rust, algae or sludge in water and will breed rapidly if the temperature of water is between 20 and

45oC. Any water containing this bacterium which is spayed or splashed creating air-borne

droplets can produce a form of pneumonia called Legionnaires Disease which is potentially fatal.

Legionella is not the only harmful micro-organism which can infect water, but it serves as a

useful example of the need for cleanliness.

Under the COSHH regulations, the following precautions must be observed:

Any water contained within the product must not be allowed to stagnate, i.e. the water must be

changed regularly.

Any rust, sludge, scale or algae on which micro-organisms can feed must be removed regularly,

i.e. the equipment must be cleaned regularly.

Where practicable the water should be maintained at a temperature below 20oC of above 45oC. If

this is not practicable then the water should be disinfected if it is safe and appropriate to do so.

Note that other hazards may exist in the handling of biocides used to disinfect the water.

A scheme should be prepared for preventing or controlling the risk incorporating all of the

actions listed above. Further details on preventing infection are contained in the publication “The

Control of Legionellosis including Legionnaires Disease” – Health and Safety Series booklet HS

(G) 70.

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Use of earth leakage circuit breaker as an electrical safety

Device

The equipment described in this Instruction Manual operates from a mains voltage electrical

supply. The equipment is designed and manufactured in accordance with appropriate regulations

relating to the use of electricity. Similarly, it is assumed that regulations applying to the

operation of electrical equipment are observed by the end user.

However, to give increased operator protection, Armfield Ltd has incorporated a Residual

Current Device or RCD (alternatively called an Earth Leakage Circuit Breaker – ELCB) as an

integral part of this equipment. If through misuse of accident the equipment becomes electrically

dangerous, an RCD will switch off the electrical supply and reduce the severity of any electric

shock received by an operator to a level which, under normal circumstances, will not cause

injury to that person.

At least once each month, check that the RCD is operating correctly by pressing the TEST

button. The circuit breaker MUST trip when the button is pressed. Failure to trip means that the

operator is not protected and the equipment must be checked and repaired by a competent

electrician before it is used.

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fluid friction apparatus final!!

Documents

turbulent flow

laminar flow

flow of water

flow measurement techniques

reynolds number

pipe fittings

head losses

experiment date