Section 9 Flashcards
Glass pipes can be joined by
a. flanges
b. welding
c. soldering
d. bell and spigot joint
d. bell and spigot joint
If two capillary tubes of dia 0.5 mm and 1 mm are dipped in a pot containing mercury, then the rise of mercury is
a. same in both the tubes.
b. greater in 1 mm dia tube.
c. greater in 0.5 mm dia tube.
d. zero in both the tubes.
c. greater in 0.5 mm dia tube.
Weber number is the ratio of inertial force to __________ force.
a. surface tension
b. gravity
c. viscous
d. elastic
a. surface tension
For laminar flow of a shear thinning liquid in a pipe, if the volumetric flow rate is doubled, the pressure gradient will increase by a factor of
a. 2
b. <2
c. >2
d. 1/2
a. 2
The curve of metacentre for a floating body __________ the curve of buoyancy.
a. is always below
b. is the evolute of
c. intersects at right angle
d. is tangential to
b. is the evolute of
At what value of crank angle (roughly), no flow of water from or into the air vessel takes place in case of a double acting reciprocating pump ?
a. 40° and 140°
b. 45° and 60°
c. 90° and 80°
d. 20° and 120°
a. 40° and 140°
Which of the following is dimensionless ?
a. Angular velocity
b. Fanning friction factor
c. Specific volume
d. None of these
b. Fanning friction factor
The range of a particular rotameter can be increased by
a. use of floats of different densities.
b. no means.
c. increasing the diameter of the float.
d. decreasing the diameter of the float.
a. use of floats of different densities.
A liquid is pumped at the rate of 600 litres using 1000 rpm. If the rpm is changed to 1100, the liquid pumped is __________ litres.
a. 600
b. 660
c. 1.1
d. 60
b. 660
A compressor that takes suction at a pressure below atmospheric and discharge against atmospheric pressure is called a __________ pump.
a. sump
b. volute
c. vacuum
d. submerged
c. vacuum
A streamline is a line in flow field,
a. that is traced by all the fluid particles passing through a given point.
b. along which a fluid particle travels.
c. such that at every point on it, the velocity is tangential to it.
d. none of these.
c. such that at every point on it, the velocity is tangential to it.
A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun’s equation for the above fluid-particle system (in SI units) is
given below : Δ P/L = 375 x 103 VOM + 10.94 x 106 V2OM (SI units)
If water is to be used as the fluidising medium, in actual operation, the above bed has a height = 1 m. What is the porosity of the fluidised bed ?
a. 0.2
b. 0.5
c. 0.7
d. 0.8
c. 0.7
Dimension of kinematic viscosity is
a. MLT^-1
b. L^2 . T^-1
c. L^2T
d. L^2 . T^-2
b. L^2 . T^-1
While starting an axial flow pump, its delivery valve should be kept
a. open
b. closed
c. either open or closed
d. none of these
b. closed
____ forces do not act in case of fluid flow.
a. Elastic
b. Tensile
c. Vibratory
d. Centrifugal
b. Tensile
Non-colloidal solution is an example of the __________ fluid.
a. non-Newtonion
b. Newtonion
c. dilatent
d. pseudoplastic
b. Newtonion
Boundary layer separation is caused by the
a. reduction of pressure below vapour pressure.
b. reduction of pressure gradient to zero.
c. adverse pressure gradient.
d. reduction of boundary layer thickness to zero.
c. adverse pressure gradient.
Identification of pipelines carrying different liquids and gases is done by the __________ of the pipe.
a. diameter
b. colour
c. altitude
d. none of these
b. colour
Pick out the correct statement.
a. Human blood is a Newtonion fluid.
b. A Newtonion fluid obeys Newton’s law of cooling.
c. For a non-Newtonion fluid, a straight line passes through the origin
in a plot between shear stress and shear gradient.
d. Thin lubricating oil is an example of a non-Newtonion fluid.
b. A Newtonion fluid obeys Newton’s law of cooling.
What is the unit of kinematic viscosity in SI unit ?
a. M^2/sec
b. N/m2 . sec
c. Kg . sec/m
d. None of these
a. M^2/sec
Hydraulic __________ works on the principle of Pascal’s law of
transmission of fluid pressure.
a. press
b. turbine
c. pump
d. coupling
a. press
A 2” gate valve fitted in a pipe is replaced by a similar globe valve. Pressure drop in gate valve was Δp. For the same discharge, the pressure drop across globe valve is
a. Δp
b. < Δp
c. Δp
d. Δp^2
c. Δp
The contraction co-efficient for Borda’s mouthpiece (for frictionless fluid) is
a. 0.1
b. 0.5
c. 0.94
d. 1
b. 0.5
Purpose of air lift pump is to
a. compress air.
b. lift compressed air.
c. lift water from a well by using compressed air.
d. lift air under negative pressure.
c. lift water from a well by using compressed air.
Pick out the correct statement pertaining to venturimeter.
a. A venturimeter with a fixed pressure drop discharges more, when the flow is vertically downward, than when the flow is vertically upward.
b. The co-efficient of contraction of a venturimeter is always unity.
c. For a fixed pressure drop, the discharge of a gas through a venturimeter is greater, when compressibility is taken into account, than when it is neglected.
d. none of these.
d. none of these.
For very low pressure and high discharge rate, the compressor used is a/an compressor.
a. axial
b. reciprocating
c. rotary
d. none of these
c. rotary
What is the speed of sound (m/sec) in ordinary water ?
a. 1500
b. 330
c. 1000
d. 300
a. 1500
Pumping of a corrosive liquid is generally preferred to be done by a __________ pump, as it can be made of a variety of materials including plastics.
a. piston
b. gear
c. positive displacement
d. sump
b. gear
Two piping system are said to be equivalent, when the __________ are same.
a. fluid flow rate & friction loss
b. length & friction factor
c. diameter & friction factor
d. length & diameter
a. fluid flow rate & friction loss
Potential function is applicable only for __________ flow.
a. irrotational
b. turbulent
c. steady
d. none of these
a. irrotational
Which of the following exemplifies a three dimensional fluid flow ?
a. Fluid flow at the inlet to a nozzle
b. Fluid flow between parallel plates
c. Viscous fluid flow between converging plates
d. None of these
a. Fluid flow at the inlet to a nozzle
Volute of a centrifugal pump should be designed in a fashion, such that the
a. kinetic head gets converted into static head.
b. moving stream gradually reduces velocity.
c. mean velocity remains constant.
d. none of these.
a. kinetic head gets converted into static head.
The head loss due to sudden contraction is proportional to
a. velocity
b. velocity head
c. turbulence
d. none of these
b. velocity head
Cavitation occurs in a centrifugal pump when the suction pressure is
a. less than the vapour pressure of the liquid at that temperature.
b. greater than the vapour pressure of the liquid at that temperature.
c. equal to the vapour pressure.
d. equal to the developed head.
a. less than the vapour pressure of the liquid at that temperature.
An ideal plastic substance indicates no deformation, when stressed upto yield stress, but behaves like a Newtonion fluid beyond yield stress. Which of the following is an ideal plastic?
a. Sewage sludge
b. Rubber latex
c. Blood
d. Sugar solution
a. Sewage sludge
The capacity of a centrifugal pump can be increased by increasing the
a. impeller diameter or speed.
b. number of pumps and joining them in series,
c. number of pumps and joining them in parallel.
d. all (a), (b) and (c).
d. all (a), (b) and (c).
Which law is followed by the velocity distribution in the turbulent boundary layer?
a. Parabolic law
b. Linear law
c. Logarithmic law
d. None of these
c. Logarithmic law
The losses in open channel flow generally vary as the
a. inverse of the roughness.
b. first power of the roughness.
c. square of the velocity.
d. inverse square of hydraulic radius.
b. first power of the roughness.
Out of the following flow measuring devices, which one incurs the maximum installation cost as well as pressure loss ?
a. Flow nozzle
b. Venturimeter
c. Rotameter
d. Orificemeter
b. Venturimeter
For turbulent fluid flow in pipe, the expression for Prandtl one seventh power law is (where, r= pipe radius, x = distance).
a. V/Vmax = (x/r)^1/7
b. V/Vmax = (r/x)^1/7
c. V/Vmax = (x.r)^1/7
d. none of these
a. V/Vmax = (x/r)^1/7
Which of the following has the maximum compression ratio?
a. Blower
b. Compressor
c. Vacuum pump
d. Fan
c. Vacuum pump
Scale up of agitator design requires
a. geometrical similarity only.
b. dynamic similarity only.
c. both geometrical and dynamic similarity.
d. all geometrical, dynamic and kinematic similarity.
d. all geometrical, dynamic and kinematic similarity.
The actual velocity at vena-contracta for flow through an orifice from a reservoir is given by
a. Cv . sqrt (2gH)
b. Cc . 2gH
c. Cd . 2gH
d. Cv . Va
a. Cv . sqrt (2gH)
The head loss in turbulent flow in pipe is proportional to(where, V = velocity of fluid through the pipe)
a. V^2
b. 1/V^2
c. 1/V
d. V
a. V^2
Unsteady non-uniform flow is represented by flow through a/an
a. long pipe at constant rate.
b. long pipe at decreasing rate.
c. expanding tube at increasing rate.
d. expanding tube at constant rate.
c. expanding tube at increasing rate.
A centrifugal pump has the following specifications:
Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, then the new head will be __________ metres.
a. 2
b. 4
c. 8
d. 5.5
a. 2
Prandtl number is a measure of the
a. heat conduction to viscosity of a fluid.
b. Cp/Cv of a fluid.
c. elastic force to pressure force in the fluid flow.
d. inertial force to elastic force in the fluid flow.
a. heat conduction to viscosity of a fluid.
In hindered settling, the particles are
a. placed farther from the wall.
b. not affected by other particles and the wall.
c. near each other,
d. none of these.
c. near each other,
