FLUID MECHANICS AND MACHINERY An Introduction

UNIT I-BASIC CONCEPTS AND PROPERTIES Fluid definition, distinction between solid and fluid - Units and dimensions - Properties of fluids - density, specific weight, specific volume, specific gravity, temperature, viscosity, compressibility, vapour pressure, capillary and surface tension - Fluid statics: concept of fluid static pressure, absolute and gauge pressures - pressure measurements by manometers and pressure gauges.

Fluid Mechanics

Fluid mechanics is that branch of science which deals with the behaviour of fluids (liquids or gases) at rest as well as in motion. Thus this branch of science deals with the static, kinematics and dynamic aspects of fluids. The study of fluids at rest is called fluid statics. The study of fluids in motion, where pressure forces are not considered, is called fluid kinematics and if the pressure forces are also considered for the fluids in motion, that branch of science is called fluid dynamics.

Field of Fluid Mechanics can be divided into 3 branches:Fluid Statics: mechanics of fluids at restKinematics: deals with velocities and streamlines w/o considering forces or energyFluid Dynamics: deals with the relations between velocities and accelerations and forces exerted by or upon fluids in motion

APPLICATIONSMechanics of fluids is extremely important in many areas of engineering and science. Examples are:BiomechanicsBlood flow through arteriesMeteorology and Ocean EngineeringMovements of air currents and water currentsChemical EngineeringDesign of chemical processing equipment

Mechanical EngineeringDesign of pumps, turbines, air-conditioning equipment, pollution-control equipment, etc.Civil EngineeringTransport of river sedimentsPollution of air and waterDesign of piping systemsFlood control systems

Dimensions and UnitsBefore going into details of fluid mechanics, we stress importance of unitsIn U.S, two primary sets of units are used: 1. SI (Systeme International) units2. English units

Unit Table

QuantitySI UnitEnglish UnitLength (L)Meter (m)Foot (ft)Mass (m)Kilogram (kg)Slug (slug) = lb*sec2/ftTime (T)Second (s)Second (sec)Temperature ( )Celcius (oC)Farenheit (oF)ForceNewton (N)=kg*m/s2Pound (lb)

UNIT II-FLUID KINEMATICS AND BOUNDARY LAYER CONCEPTSFluid Kinematics - Flow visualization - lines of flow - types of flow - continuity equation (one dimensional differential forms)- fluid dynamics - equations of motion - Euler's equation along a streamline - Bernoulli's equation applications - Venturi meter, Orifice meter, Pitot tube - Boundary layer flows, boundary layer thickness, boundary layer separation - drag and lift coefficients.

UNIT III-FLOW THROUGH PIPESViscous flow - Navier - Stoke's equation (Statement only) - Shear stress, pressure gradient relationship - laminar flow between parallel plates - Laminar flow through circular tubes (Hagen poiseulle's) - Hydraulic and energy gradient - flow through pipes - Darcy -weisback's equation - pipe roughness -friction factor-minor losses - flow through pipes in series and in parallel - power transmission

UNIT IV-DIMENSIONAL ANALYSIS AND HYDRAULIC TURBINESDimensional analysis - Buckingham's theorem- applications - similarity laws and models.Hydro turbines: definition and classifications - Pelton turbine - Francis turbine - Kaplan turbine - working principles - velocity triangles - work done - specific speed - efficiencies -performance curve for turbines.

UNIT V-PUMPS Pumps: definition and classifications - Centrifugal pump: classifications, working principles, velocity triangles, specific speed, efficiency and performance curves - Reciprocating pump: classification, working principles, indicator diagram, work saved by air vessels and performance curves - cavitations in pumps -priming- slip- rotary pumps: working principles of gear, jet and vane pumps.

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