FLUID MECHANICS AND MACHINERY U3MEA03 Prepared by Mr. Kannan, Assistant Professor, Mechanical Department VelTech Dr.RR & Dr.SR Technical University

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 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.

 Fluid Statics: mechanics of fluids at rest  Kinematics: deals with velocities and streamlines w/o considering forces or energy  Fluid Dynamics: deals with the relations between velocities and accelerations and forces exerted by or upon fluids in motion

Mechanics of fluids is extremely important in many areas of engineering and science. Examples are:  Biomechanics ◦ Blood flow through arteries  Meteorology and Ocean Engineering ◦ Movements of air currents and water currents  Chemical Engineering ◦ Design of chemical processing equipment

 Mechanical Engineering ◦ Design of pumps, turbines, air-conditioning equipment, pollution-control equipment, etc.  Civil Engineering ◦ Transport of river sediments ◦ Pollution of air and water ◦ Design of piping systems ◦ Flood control systems

 Before going into details of fluid mechanics, we stress importance of units  In U.S, two primary sets of units are used: ◦ 1. SI (Systeme International) units ◦ 2. English units

QuantitySI UnitEnglish Unit Length (L)Meter (m)Foot (ft) Mass (m)Kilogram (kg)Slug (slug) = lb*sec 2 /ft Time (T)Second (s)Second (sec) Temperature ( )Celcius ( o C)Farenheit ( o F) ForceNewton (N)=kg*m/s 2 Pound (lb)

Fluid 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.

Viscous 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

Dimensional 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.

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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