fm 2 Flashcards
A globe valve is the most suitable for applications, in which
fluid flow control is required.
fluid contains dispersed solid particles.
valve is required to be either fully open or fully closed.
one way flow is required.
A
__________ isused for measuring the static pressure exerted on the wall by a fluid flowing parallel to the wall in a pipeline.
Venturimeter
Pressure gauge
Pitot tube
Orificemeter
C
One stoke (unit of kinematic viscosity) is equivalent to
1 cm2/second
1 m2/second
1 gm/cm. second
1 kg . m/second
A
Air vessel of a reciprocating pump is initially filled with
atmospheric air
compressed air
water
none of these
B
The ratio of inertial forces to gravity forces is called the __________ number.
Mach
Froude
Euler
Weber
B
Power required by a centrifugal pump is proportional to (where, D = diameter, N = r.p.m)
N2D3
ND2
N2D
N3D5
D
Equivalent length of a pipe fitting is
dependent on Reynolds number.
independent of Reynolds number.
dependent on the length of the pipe.
none of these.
A
Buckingham-π theorem states that in any physical problem including ‘n’ quantities having ‘m’ diamensions, the quantities can be arranged into __________ independent dimensionless parameters.
m
n
n-m
n/m
C
A fluid which has a linear relationship between the magnitude of applied shear-stress and the resulting rate of deformation is called a/an __________ fluid.
Newtonion
Non-Newtonion
ideal
incompressible
A
Existence of boundary layer in fluid flow is because of the
surface tension
fluid density
fluid viscosity
gravity forces
C
In case of laminar flow of fluid through a circular pipe, the
A. shear stress over the cross-section is proportional to the distance from the surface of the pipe.
B. surface of velocity distribution is a paraboloid of revolution, whose volume equals half the volume of circumscribing cylinder.
C. velocity profile varies hyperbolically and the shear stress remains constant over the cross-section.
D.average flow occurs at a radial distance of 0.5 r from the centre of the pipe (r = pipe radius).
B
Which of the following facilitates close control of flow of fluids ?
Gate valve
Globe valve
Butterfly valve
Check valve
B
Fanning friction factor equation applies to the __________ fluid flow.
non-isothermal condition of
compressible
both (a) and (b)
neither (a) nor (b)
D
For an ideal fluid flow, Reynolds number is
2100
100
0
∞
D
Stoke’s equation is valid in the Reynolds number range
0.01 to 0.1
0.1 to 2
2 to 10
10 to 100
A
When a fluid flows over a solid surface, the
velocity is uniform at any cross-section.
velocity gradient is zero at the solid surface.
resistance between the surface & the fluid is lesser as compared to that between the fluid layers themselves.
velocity is not zero at the solid surface.
B
Pick out the wrong statement about cavitation.
Sudden reduction of pressure in a fluid flow system caused by flow separation, vortex formation or abrupt closing of valve leads to cavitation.
Cavitation may be caused due to boiling of liquid by decreasing the pressure resulting in formation & collapse of vapor cavities.
Cavitation begins at higher static pressure and lower velocity in larger diameter pipelines resulting in audible noise.
Large scale cavitation can not damage pipeline, restrict fluid flow and damage steam turbine blades.
D
The maximum delivery pressure of a reciprocating compressor may be about __________ kg/cm2.
1000
2000
3000
4000
D
The velocity for subsonic flow in a pipeline
increases in the downstream direction.
is constant.
decreases in the downstream direction.
is independent of the area of flow.
A
Permanent pressure loss in a well designed venturimeter is about __________ percent of the venturi differential.
1
10
30
50
B
The ratio of pressure forces to inertial forces is called the __________ number.
Froude
Euler
Reynold
Mach
B
Bernoulli’s equation for fluid flow is derived following certain assumptions. Out of the assumptions listed below, which set of assumptions is used in derivation of Bernoulli’s equation ?
A. Fluid flow is frictionless & irrotational.
B. Fluid flow is steady.
C. Fluid flow is uniform & turbulent.
D. Fluid is compressible.
E. Fluid is incompressible.
A, C, D
B, D, E
A, B, E
A, D, E
C
Cavitation in a centrifugal pump results from
high discharge pressure
low barometric pressure
high discharge velocity
high discharge rate
B
For turbulent flow of newtonion fluid in a circular cross-section pipe, the ratio of maximum to average fluid velocity is
0.5
1
0.66
< 0.5
B
For flow through a venturi at a particular discharge, the correct relationships among heads at points X, Y, and Z are
h1 > h2 < h3
h1 > h2 > h3
h2 < h1 < h3
h1 < h2 < h3
A
Water is flowing at 1 m/sec through a pipe (of 10 cm I.D) with a right angle bend. The force in Newtons exerted on the bend by water is
102π
5π/2
52π
5π/2
B
he time of oscillation of a floating body is
longer, if metacentric height is increased.
independent of the metacentric height.
dependent on the buoyant forces only.
none of these.
D
What is the value of Fanning friction factor f ‘ for smooth pipe at NRe = 106 approximately ?
0.003
0.01
0.1
0.3
A
The hydraulic radius for flow in a rectangular duct of cross-sectional dimension H, W is
B
In magnetic flow meters, voltage generation is
due to the motion of conducting fluid through an externally generated uniform field.
proportional to the fluid velocity.
both (a) and (b).
neither (a) nor (b).
C
Air vessel provided in a reciprocating pump is for
increasing the acceleration head.
making the friction in pipe uniform.
decreasing the acceleration head.
none of these.
B
A hydraulic accumulator comprises of
a storage device and a control valve.
a cylinder and a plunger.
two pistons and two cylinders.
a storage tank and a ram pump.
B
Bernoulli’s equation for steady, frictionless, continuous flow states that the __________ at all sections is same.
total pressure
total energy
velocity head
none of these
B
A tube is specified by its
thickness only
outer diameter only
thickness & outer diameter both
inner diameter
C
Uniform fluid flow occurs, when the derivative of the flow variables satisfy the following condition.
C
Prandtl mixing length is
applicable to laminar flow problems.
a universal constant.
zero at the pipe wall.
none of these.
C
The hydraulic diameter of an annulus of inner and outer radii Ri and Ro respectively is
4(Ro-Ri)
Ro-Ri
2(Ro-Ri)
Ro + Ri
C
Ratio of inertial forces to surface tension forces is called the __________ number.
Euler
Froude
Mach
Weber
D
In open channel flow in a rectangular channel, the ratio between the critical depth and the initial depth, when a hydraulic jump occurs is
0.5
0.84
1.84
1.25
C
The ratio of inertial forces to viscous forces is called the __________ number.
Weber
Mach
Froude
Reynold
D
Enamels and paints are generally __________ fluid.
reheopectic
pseudo-plastic
thixotropic
dilatant
B
With the increase in depth, the hydrostatic pressure in an unaccelerated incompressible fluid (in a constant gravitational field)
decreases.
increases linearly.
increases exponentially.
remains constant.
B
Flow measurement in an open channel is done by a/an
venturimeter
orificemeter
weir
rotameter
C
Newton’s law of viscosity relates the
shear stress and velocity.
velocity gradient and pressure intensity.
shear stress and rate of angular deformation in a fluid.
pressure gradient and rate of angular deformation.
C
Applicability of Bernoulli’s equation is limited to a/an __________ fluid, that does not exchange shaft work with the surroundings.
incompressible
non-viscous
both (a) and (b)
neither (a) nor (b)
C
The equivalent diameter for fluid flow through square cross section channel of side ‘x’, for pressure drop calculation purpose is given by
4x
2x
x
SQRT x
C
Hydraulic radius of 6” x 12” cross-section, is __________ inches.
2
0.5
1.5
none of these
A
Baffles in mixing tanks are provided to
reduce swirling and vortex formation.
increase the structural strength of the tank.
aid in rotational flow.
none of these
A
Which of the following equations is valid for laminar flow of a fluid through packed bed?
Fanning equation
Kozney - Karman equation
Hagen-Poiseuille equation
Blake-Plummer equation
B
A pipe has a porous section of length L as shown in the figure. Velocity at the start of this section of V0. If fluid leaks into the pipe through the porous section at a volumetric rate per unit area q(x/L)2, what will be axial velocity in the pipe at any x ? Assume incompressible one dimensional flow i.e., no gradients in the radial direction.
D
Forces acting on a particle settling in fluid are __________ forces.
gravitational & buoyant.
centrifugal & drag.
gravitational or centrifugal buoyant drag.
external, drag & viscous.
C
For a fluid rotating at constant angular velocity about vertical axis as a rigid body, the pressure intensity varies as the
square of the radial distance.
radial distance linearly.
inverse of the radial distance.
elevation along vertical direction.
A
In a dry packed bed, the pressure drop will be changed by increasing the flow rate as
V1.8
V-0.8
V
V-1
A
Specific speed of a centrifugal pump depends upon the __________ head.
suction
delivery
manometric
none of these
D
Navier-Stokes equation is useful in the analysis of __________ fluid flow problems.
non-viscous
viscous
turbulent
rotational
B
The maximum discharge through a circular channel takes place, when the depth of the fluid flow is __________ times the pipe diameter.
0.25
0.5
0.66
0.95
d
When the head pumped against is less than the head of the fluid used for pumping, the usual device is a/an
ejector
blower
injector
airlift
D
Two fluids are flowing through two similar pipes of the same diameter. The Reynold’s number is same. For the same flow rate if the viscosity of a fluid is reduced to half the value of the first fluid, the pressure drop will
increase
decrease
remain unchanged
data insufficient to predict relative pressure drop.
B
What is the value of co-efficient of discharge for square edged circular orifice (for β = 0.3 to 0.5) ?
0.61 - 0.63
0.5 - 0.75
0.75 - 0.90
0.35 - 0.55
A
A lubricant 100 times more viscous than water would have a viscosity (in Pa.s)
0.01
0.1
1
10
B
Nominal Pipe Size (NPS) of a pipe less than 12 inches in diameter indicates its
inner diameter
outer diameter
thickness
neither inner nor outer diameter
D
I.D. of 1/4” schedule 40 pipe is 0.364”. I.D. of a 1/2” schedule 40 pipe would be __________ inch
4.728
0.5
0.622
0.474
C
A pump operating under specific conditions delivers insufficient quantity of liquid. This may be set right by
decreasing the size of the inlet pipe.
increasing the size of the inlet pipe.
lowering the pump position.
both (b) and (c).
D
wo liquids manometer is used for measuring small pressure differences in
liquids
gases
mixture of hydrocarbons
none of these
B
A piezometer provided in the pipe measures
friction factor
static pressure
dynamic pressure
none of these
B
The pump used for irrigation purposes is generally designed for
large capacity & high head.
large capacity & low head.
small capacity & high head.
small capacity & low head.
B
In centrifugal pumps, cavitation occurs, when pressure of the impeller eye or vane becomes
less than atmospheric pressure.
more than liquid vapor pressure.
less than liquid vapor pressure.
more than atmospheric pressure.
C
Pressure gradient in the pipe flow is influenced by the
diameter of pipe.
velocity of the fluid.
density & viscosity of the fluid.
all (a), (b) and (c).
D
__________ pump is the most suitable device for discharging a liquid against a pressure of ≥ 1500 kgf/cm2.
Centrifugal
Piston
Plunger
Vane
C
Boiler feed water pump is usually a __________ pump.
reciprocating
gear
multistage centrifugal
diaphragm
C
Viscosity of a liquid decreases __________ with rise in temperature.
exponentially
linearly
logarithmically
none of these
C
Viscosity of a liquid decreases __________ with rise in temperature.
exponentially
linearly
logarithmically
none of these
A
Discharge in laminar flow through a pipe varies
as the square of the radius.
inversely as the pressure drop.
inversely as the viscosity.
as the square of the diameter.
A
The lift of a ballon is
increased, as it rises to a higher altitude.
due to the weight of the atmospheric air, that it displaces.
not dependent on the temperature of the atmosphere.
none of these.
B
In which of the following body shapes, the pressure drag is large compared to the friction drag ?
Stream line body
Two dimensional body
Bluff body
None of these
C
Major loss in sudden contraction in pipe flow is due to
boundary friction.
flow contraction.
expansion of flow after sudden contraction.
none of these.
B
Which of the following can be used to create a flow of gas, where no significant compression is required ?
Reciprocating compressor
Blower
Axial flow compressor
Centrifugal compressor
B
The ratio of actual discharge to theoretical discharge through an orifice is equal to
Cc . Cv
Cc . Cd
Cv . Cd
Cd/Cv
A
A free jet of water of cross-sectional area 0.01m2 and a velocity of 20 m/s strikes a plate and then flows in a plane parallel to the plate as shown in the figure below. The horizontal component of the force on the support is
200 N
400 N
2000 N
4000 N
D
Cp/Cv is termed as
adiabatic constant
Mach number
Weber number
Prandtl number
A
Which of the following is a Newtonian fluid?
Rubber latex
Sewage sludge
Quicksand
Non-colloidal solution
D
Which of the following valves will incur maximum pressure drop for the same discharge of water ?
Globe valve
Gate valve
Needle valve
Butterfly valve
C
Pressure drop in a fluidised bed reactor is __________ that in a similar packed bed reactor.
less than
more than
same as
none of thes
B
In deriving Bernoulli’s equation, fluid is assumed to be
incompressible, frictionless, steady, along a streamline.
uniform, steady, incompressible, along a streamline.
steady, density being pressure dependent, frictionless.
none of these.
A
nit of mass velocity is
kg/hr
kg/m2. hr
kg/m2
kg/m3. hr
B
With increase in molecular weight of the gas, the head developed by a centrifugal compressor will
decrease
increase
remain same
unpredictable
A
Pressure difference between two points in vessels, pipelines or in two different pipelines can be measured by a differential manometer. The pressure difference measured as the mm of water coloumn in case of mercury-water, differential manometer is equal to (where, H = difference in height of mercury column in mm).
H
12.6 H
13.6 H
14.6 H
B
The boundary layer thickness at a given section along a flat plate __________ with increasing Reynold’s number.
increases
decreases
remains same
may increase or decrease
B
Low specific speed of a pump implies that, it is a/an __________ pump.
axial flow
centrifugal
mixed flow
none of these
B
Pressure drop for laminar fluid flow through a circular pipe is given by
B
For pumping slurry, one can use a __________ pump.
reciprocating
diaphargm
centrifugal
pneumatic
B
Bernoulli’s equation describes the
mechanical energy balance in potential flow.
kinetic energy balance in laminar flow.
mechanical energy balance in turbulent flow.
mechanical energy balance in boundary layer.
A
For laminar flow of a fluid through a packed bed of spheres of diameter d, the pressure drop per unit length of bed depends upon the sphere diameter as
d
d2
d4
-D2
D
Which law/principle of solid mechanics is similar/equivalent to Newton’s law of viscosity in fluid mechanics ?
Archimedes principle.
Newton’s second law of motion.
Hooke’s law.
Newton’s third law of motion.
C
When larger particles e.g., grains are subjected to fluidisation, the corresponding bed produced is termed as the __________ bed.
spouted
sluggish
boiling
teeter
A
Minimum fluidisation velocity for a specific system depends upon the
particle size.
fluid viscosity.
density of both the particle & the fluid.
all (a), (b) and (c).
D
Potential flow is characterised by the
irrotational and frictionless flow.
irrotational and frictional flow.
one in which dissipation of mechanical energy into heat occurs.
formation of eddies within the stream.
A
For the production of very high vacuum, a __________ pump is normally used.
diffusion
centrifugal
jet ejector
piston
A
In parallel pipe problems, the
head loss is the same through each pipe.
discharge is the same through all the pipes.
total head loss is equal to the sum of the head losses through each pipe.
none of these.
A
Fluid flow through a packed bed is represented by the __________ equation.
Fanning’s
Ergun’s
Hagen-Poiseuille’s
none of these
B
