Books Recommended
 McCabe Warren L., Smith Julian C., Harriott peter “Unit Operations
of chemical Engineering” 6th Ed. 2001. McGraw Hill Inc.
 Coulson J.M., Richardson J.F. “Chemical Engineering” Vol-I, 1985.
The English Book Society and Pergamon Press.
 Holland, F.A. & Bragg, R. “Fluid flow for Chemical Engineers”,
2nd Edition,
 Butterworth & Heinemann. 1995.
 White, F.M. “Fluid Mechanics”, 4th Edition, McGraw-Hill. 1999.
 Noel-de-Nevers “Fluid Mechanics for Chemical Engineers” McGraw
Hill
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Why We Study Fluid Mechanics?
Human Body (Blood circulation in veins/
capillaries, Heart as pump)
Municipal Water Supply (Pumping stations &
distribution)
Natural Gas Transmission (Compression &
distribution)
Oil Supply Karachi to Mehmood Kot ;Parco
(Pumping stations/ pipelines) Petrol Pumps etc.
Application in every INDUSTRY.
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What We Will Study
 Concept & Use of Units, Dimensional Analysis: Bukingham –Pi
Theorem, Reynold’s law of Similarity.
 Fluid Statics: pressure forces on surfaces, Pressure
distribution,
Head Calculations, pressure measuring
devices, Buoyancy,. Pressure in accelerated rigid body motions.
 Nature of Flow: Laminar & Turbulent Flow, Compressible &
Non-Compressible.
 Bernoulli’s equation and its applications; Continuity
Equation, Energy Relationships & the Bernoulli equation,
pressure terminology, diffusers and sudden expansion.
 Momentum of a Flowing Fluid; Newton’s 2nd law of motion
& Momentum Balance, Calculations for Laminar&
Turbulent pipe flow, nozzle flow & other examples. Stress
in Fluids; Viscosity, Newton’s Law of Viscosity, Shear Stress
Components, Newtonian and non-Newtonian flow.
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 Turbulence & Boundary Layers; Concept of Eddies as a source
to sustain Turbulence, Velocity Fluctuations & Reynolds
Stresses, Transport Properties and Prantl’s Power Law Velocity
Profile, Laminar & Turbulent Boundary Layers over a flat plate
 Flow of Incompressible Newtonian Fluids in Pipes & Channels
 Shear stress in a pipe, Friction factor & pressure drop, Losses in
fittings and bend pipes, enlargements and contractions,
friction in non-circular channels, Velocity distribution for
turbulent flow in a pipe.
 Flow of Compressible Newtonian Fluids
 The Mach Number, Equation of State, Adiabatic and Isentropic
Steady Flow, Isentropic Flow with Area Changes, One dimensional
high velocity gas flows, Choking flow, Shock waves, nozzles and
diffusers .
 Gas-Liquid Two-phase Flow
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 Flow patterns and flow regime maps, Momentum equation for two-
phase flow, two-phase flow parameters, Bubbly flow, Slug flow in
vertical tubes, The homogenous model for two-phase flow, Separated
flow models, Drift-flux Calculations.
 Fluid Motion in the Presence of Solid Particles
 Relative motion between a fluid and a single particle, Effect of
presence of other particles and wall on the particle velocity, Flow
through packed beds, Fluidization, Slurry transport and
Filtration.
 Flow of Non-Newtonian Fluids
 Elementary viscometry, Rabinowtisch -Mooney Equation, Calculation
of flow rate-pressure drop relationship for laminar flow,
Generalized Reynolds number for flow in pipes, Turbulent flow of
inelastic non-Newtonian fluids in pipes, Power Law Fluids, Pressure
drop for Bingham plastics in laminar flow, Viscoelasticity.
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Density
• Mass per unit volume: kg/m3, lbm/ft3,
gm/cm3
Specific
Volume
• Inverse of density: m3/kg, ft3/lbm,
cm3/gm
Viscosity
• Internal resistance to flow of fluid:
gm/cm.sec, lbm/hr.ft
Shear
Stress
• Shear stress is defined as the ratio of
force parallel to flow to the area of layer.
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Fluid
• A fluid is defined as substance that doesn't resist
permanent distortion. An attempt to change a
shape of a mass of fluid results in layers of fluids
sliding over one another until a new shape is
attained- during a change in shape, shear stress
exits: the magnitude of which depends upon the
viscosity of the fluid and the rate of sliding.
• When the final shape has been reached all shear
stress will be disappeared. So a fluid in
equilibrium is free from shear stress.
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Fluid Mechanics
The branch of engineering science which deals with the behavior
of fluid at rest or in motion is called FLUID MECHANICS.
It has two sub branches:Fluid Statics
Fluid Dynamics
Fluid Statics
It deals with the fluid equilibrium state of no shear stress
means when fluid is at rest.
Fluid Dynamics
It deals with the fluid when a portion of fluid is in motion
in relation to other parts.
The study of behavior of the fluid is an important engineering
process and understanding a fluid is essential not only for the
accurate measurement & movement of the fluid through pipes,
pumps and all kinds of process equipments but also for the study
of heat flow and many separation operations.
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Types
of
Fluids
• Incompressible Fluids
• Compressible Fluids
• Incompressible Fluids
• If the density changes only slightly with
significant changes in temperature &
pressure the fluid is said to be
incompressible.
• Compressible Fluids
• If the changes in density are significant with
change in temperature & pressure those
fluids are said to be compressible fluids.
• Liquids are generally considered to be
incompressible
while
gases
are
compressible.
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Types of Flow
• Steady State Flow
• Un-Steady State Flow
• Steady State Flow
• Suppose the mass, flow rate, temperature, pressure,
composition & density are not changing with time or
function of time, or , are constant with time then flow
will be termed as steady state flow.
• Un- Steady State Flow
• If mass, flow rate, temperature, pressure, composition
& density are changing with time or function of time
then the flow is said to be unsteady state flow.
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Laminar
Flow
• This is type of flow in which
no mixing of layers takes
place.
• No eddies are formed during
flow. The value of reynold’s
number is upto 2000-2100.
Turbulent
Flow
• This is type of flow in which
mixing of layers takes place
and eddies are formed during
flow. The value of reynold’s
number is greater than 40004200.
Nature of
Flow:
Transition
Flow
• Flow between laminar and
turbulent flow is called
transition flow. The value of
reynold’s number is between
2100-4200.
• In this type of flow layers try
to mix with each other but
layers remain mostly separate.
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