3

Bangladesh University of Engineering and

Technology

Course Number: Group Number:

Course Title:

Experiment Number:

Name of the Experiment(s):

Date of Performance:

Date of Submission:

Submitted By

Name:

Student ID:

Department:

Section:

ME 306

Heat Transfer Sessional

Evaluation Sheet

Experiment No Lab Report (10) Viva (10) Assessment (10) Total

1 2 3 4

Total

1

EXPERIMENT NO: 1(a)

Determination of Thermal Conductivity of a Metal by Steady State Method

Objectives:

a)

b)

c)

Apparatus: (Please mention the details of each apparatus used for this experiment)

Schematic Diagram:

2

DATA AND CALCULATION SHEET

Test Date :

Thermocouple Used :

Room Temperature (oC) :

Water Inlet Temperature (oC) :

Water Outlet temperature (oC) :

Weight of Container + Water (kg) :

Weight of Water Collected (kg) :

Time of Collection (sec) :

Mass flow rate of Water (kg/sec) :

Table-1: Steady-State Temperature Distribution in the Specimen.

Obs. Section Distance x(m) Dimensionless

Distance x/L

Temperatures

Experimental

(Thermocouple Readings),

Te (oC)

Theoretical, Tt

(oC)

1

1

2

3

4

5

2

1

2

3

4

5

3

Table-2: Calculation of Thermal Conductivity.

Obs.

Mass flow

rate of water,

mw (kg/sec)

Temperature

rise of water,

Δtw (K)

Heat carried

away by

water, (W)

Cross-sectional

area of

specimen (m2)

dT/dx from

plot of Te vs.

x (K/m)

Thermal conductivity

of specimen, k

(W/mK)

1

2

Please bring normal mm graph papers for this experiment.

Sample Calculation

4

5

Results

Discussion

6

EXPERIMENT NO: 1(b)

Determination of Thermal Conductivity of Fluid

Objectives:

Apparatus: (Please mention the details of each apparatus used for this experiment)

Schematic Diagram:

7

DATA AND CALCULATION SHEET

Nominal Resistance of Heating Element 55

Nominal Radial clearance between Plug and Jacket, r 0.34 mm

Effective Area of conducting path through fluid

Fluid

Plug Surface Temperature, t1

Jacket surface temperature, t2

Heater Voltage, V

Calculation

Element Heat Input, R

VQ

c

2

Temperature Difference, t = t1 – t2

Incidental Heat Transfer at t, Qi =

Heat Transfer by conduction through the Oil, Qc = Qe - Qi

Thermal Conductivity of Oil sample, tA

rQK

c

oil

Results

Discussion

8

Assessment

9

1

Experiment 2

Determination of Radiation Heat Transfer

Objectives:

Apparatus (with specifications where necessary):

2

Schematic Diagram of Experimental Setup (Name the missing components below the figure):

E

D

B

A

C

F

3

Results:

Thermocouple type:

Thermocouple material:

Thermocouple temperature range, (oC):

Room temperature, T∞ (oC) =

Barometric Pressure, ha (mmHg) =

Diameter of solid element, D (m) =

Area of solid element surface, A (m2) =

Measured Data:

Number of

observations

Voltage, V

in volts

Current, I

in amps

U-tube

manometer

reading in

mmHg

Element

temperature

Th in oC

Vessel temperature

Tc in oC

1

2

3

4

5

6

7

8

Calculated Result:

Number of

observations

Supplied

heat Qs

in W

Element

temperature

Th in K

Vessel

temperature

Tc in K

Temperature

difference

Th – Tc in K

Absolute

pressure

H in

mmHg

𝐻14

Radiation

heat loss

QR in W

Convection

heat loss

QC in W

1

2

3

4

5

4

6

7

8

Sample Calculation:

5

Graphical Representations:

a) Variation of (Th -Tc) with 𝐻1

4 .

b) Variation of Radiation Heat transfer with (Th - Tc)

6

Discussions: Discussion must contain appropriate explanation of the following facts.

a) Nature of curves of (Th -Tc) with 𝐻1

4 and QR vs (Th - Tc)

b) Variation of radiation heat transfer with convective heat transfer

c) Limitations of the experimental setup, if there are any (Try to observe and think critically,

you would definitely find out that).

7

Conclusions: Conclusions must account the following facts

a) Calculated value of emissivity and radiation heat transfer coefficient found from the

experiment.

b) Mentioning the discrepancies of experimental values and actual values from

literature(just mention them, no explanation is required)

8

Class Assessment:

1

Experiment No. 3

Study of Boiling Heat Transfer

Objectives:

1)

2)

3)

4)

5)

Apparatus: (Please mention the details of each apparatus used for this experiment)

Experimental Set Up:

Fig. A Schematic of the Setup for Boiling Study

2

Data Table:

Sample Calculation:

1. Heat supplied, Qs(W)

Qs = VI (1)

Where, V is the voltage in volts in volts and I is the current flowing through element in amps. Here

we neglect the power losses in lead wires.

2. Heat flux, q(W/m2)

The effective heat transfer area of the element, A is 1.3 x10-3m2. Heat flux is calculated dividing

Eq. (1) by A as given follows:

q = Qs/A (2)

Data at pressure P

= ............Pa

Number of Observations

1 2 3 4 5 6 7 8 9

To b

e M

easu

red

Voltage,

V(volt)

Current, I

(amp)

Element Temp.

Tw(oC)

Liquid Temp.

Ts(oC)

Water Inlet

Temp. Twi(oC)

Water Inlet

Temp. Two(oC)

Water Flow

Rate, m/t (kg/s)

To b

e C

alc

ula

ted

Qs (W)

q (W/m2)

TsatoC

h (W/m2K)

Qc(W)

TmoC

U(W/m2K)

3

3. Wall superheat, TsatoC

Wall superheat (sometimes called excess temperature) is defined as follows

Tsat = Tw –Ts (3)

Where Tw is the surface temperature of the element and Ts is the saturation temperature of the

liquid.

4. Boiling Heat Transfer Coefficient, h (W/m2K)

Boiling heat transfer coefficient, h can be calculated using Ep. (4)

h = q/Tsat (4)

5. Overall Heat Transfer Coefficient, U (W/m2K)

Heat transfer during condensation can be calculated using the following relation:

Qc = UAcTm (5)

Where Ac = 0.032 m2 is the condenser area exposed to cooling water and Tm is the logarithmic

mean temperature difference (LMTD). Qc and Tm can be calculated using the following relations:

T = (Two – Twi) (6)

Qc = .

m CpT (7)

Tm = ( i – o)/ln( i/ o) (8)

i = Twi - Ts (9)

o = Two - Ts (10)

4

Cp is the specific heat of cooling water (= 4.18 kJ/KgK) and .

m the mass flow rate of water.

Results:

Boiling heat transfer co-efficient, h =

Overall Heat Transfer Coefficient, U =

Discussion:

(Briefly explain the boiling curve obtained in the experiment and compare with one mentioned in

any heat transfer books. Comment on critical heat flux and boiling heat transfer co-efficient.)

5

Assessment:

6

1

EXPERIMENT 4

Study of Forced Convection Heat Transfer Over a Flat Plate

Objectives:

a)

b)

c)

Apparatus: (Please mention the details of each apparatus used for this experiment)

Schematic Diagram:

2

Forced Convection over a Flat Plate

Material of the plate is copper

Length of copper plate, L = ………m

Width of the copper plate, W = ……...m

Thermocouple used:

Type:_______, Material: _________________________, Range: ______________________

Room temperature, T∞ = …….. °C

Density of air at room temperature, ρair = …….. kg/m3

Density of water at room temperature, ρwater = …….. kg/m3

Emissivity of copper plate, ε = 0.78

Table 1: Collection of experimental data for different observations.

No.

of

Obs.

Power

Input,

Qin

(W)

Thermocouple reading (°C)

Inlet

Air Temp,

T∞

(°C)

Manometer

deflection of

water,

hwater

(m)

No.1

Ts1

No.2

Ts2

No.3

Ts3

No.4

Ts4

No.5

Ts5

x1 (m)

----------

x2 (m)

----------

x3 (m)

----------

x4 (m)

--------

--

x5 (m)

--------

--

1

2

3

3

Calculation Sheet

Table 2: Thermo-physical Properties of air at different film temperature.

Properties

of air

Observation No.1 Observation No.2 Observation No.3

Film temperature,

Tf = ……..........K

Film temperature,

Tf = ……..........K

Film temperature,

Tf = ……..........K

k (W/mK)

ρ (kg/m3)

μ (kg/m.s)

Pr

Calculated Result

Table 3: Calculated parameters and convection heat transfer coefficient.

Obse

rvat

ion

No.

Power

Input

Qs

(W)

Air

Velocity

V

(m/s)

Governing Parameters

Heat Transfer Coefficient, hc (W/m2K)

Empirical Correlation Thermal Balance

ReL xcr/L Pr Isothermal Isoflux Experimental

1

2

3

Please bring normal mm graph papers for this experiment.

4

Sample Calculation

5

Results

6

Assessment

7

Discussion