Section 11 Flashcards
Forces acting on a particle settling in fluid are __________ forces.
a. gravitational & buoyant.
b. centrifugal & drag.
c. gravitational or centrifugal buoyant drag.
d. external, drag & viscous.
c. gravitational or centrifugal buoyant drag.
For a fluid rotating at constant angular velocity about vertical axis as a rigid body, the pressure intensity varies as the
a. square of the radial distance.
b. radial distance linearly.
c. inverse of the radial distance.
d. elevation along vertical direction.
a. square of the radial distance.
In a dry packed bed, the pressure drop will be changed by increasing the flow rate as
a. V^1.8
b. V^-0.8
c. V
d. V^-1
a. V^1.8
Specific speed of a centrifugal pump depends upon the __________ head.
A. suction
b. delivery
c. manometric
d. none of these
d. none of these
Navier-Stokes equation is useful in the analysis of __________ fluid flow problems.
a. non-viscous
b. viscous
c. turbulent
d. rotational
b. viscous
The maximum discharge through a circular channel takes place, when the depth of the fluid flow is __________ times the pipe diameter.
a. 0.25
b. 0.5
c. 0.66
d. 0.95
d. 0.95
When the head pumped against is less than the head of the fluid used for pumping, the usual device is a/an
a. ejector
b. blower
c. injector
d. airlift
d. airlift
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
a. increase
b. decrease
c. remain unchanged
d. data insufficient to predict relative pressure drop.
b. decrease
What is the value of co-efficient of discharge for square edged circular orifice (for β = 0.3 to 0.5)?
a. 0.61 - 0.63
b. 0.5 - 0.75
c. 0.75 - 0.90
d. 0.35 - 0.55
a. 0.61 - 0.63
A lubricant 100 times more viscous than water would have a viscosity (in Pa.s)
a. 0.01
b. 0.1
c. 1
d. 10
b. 0.1
Nominal Pipe Size (NPS) of a pipe less than 12 inches in diameter indicates its
a. inner diameter
b. outer diameter
c. thickness
d. neither inner nor outer diameter
d. neither inner nor outer diameter
I.D. of 1/4” schedule 40 pipe is 0.364”. I.D. of a 1/2” schedule 40 pipe would be __________ inch
a. 4.728
b. 0.5
c. 0.622
d. 0.474
c. 0.622
Two liquids manometer is used for measuring small pressure differences in
a. liquids
b. gases
c. mixture of hydrocarbons
d. none of these
b. gases
A piezometer provided in the pipe measures
a. friction factor
b. static pressure
c. dynamic pressure
d. none of these
b. static pressure
The pump used for irrigation purposes is generally designed for
a. large capacity & high head.
b. large capacity & low head.
c. small capacity & high head.
d. small capacity & low head.
b. large capacity & low head.
In centrifugal pumps, cavitation occurs, when pressure of the impeller eye or vane becomes
a. less than atmospheric pressure.
b. more than liquid vapor pressure.
c. less than liquid vapor pressure.
d. more than atmospheric pressure.
c. less than liquid vapor pressure.
Pressure gradient in the pipe flow is influenced by the
a. diameter of pipe.
b. velocity of the fluid.
c. density & viscosity of the fluid.
d. all (a), (b) and (c).
d. all (a), (b) and (c).
__________ pump is the most suitable device for discharging a liquid against a pressure of ≥ 1500 kgf/cm2.
a. Centrifugal
b. Piston
c. Plunger
d. Vane
c. Plunger
Boiler feed water pump is usually a __________ pump.
a. reciprocating
b. gear
c. multistage centrifugal
d. diaphragm
c. multistage centrifugal
Viscosity of a liquid decreases __________ with rise in temperature.
a. exponentially
b. linearly
c. logarithmically
d. none of these
c. logarithmically
In case of a pipe of constant cross-sectional area, the maximum fluid velocity obtainable is
a. the velocity of sound.
b. dependent on its cross-sectional area.
c. dependent on fluid viscosity.
d. dependent on fluid density.
a. the velocity of sound.
Discharge in laminar flow through a pipe varies
a. as the square of the radius.
b. inversely as the pressure drop.
c. inversely as the viscosity.
d. as the square of the diameter.
a. as the square of the radius.
The lift of a ballon is
a. increased, as it rises to a higher altitude.
b. due to the weight of the atmospheric air, that it displaces.
c. not dependent on the temperature of the atmosphere.
d. none of these
b. due to the weight of the atmospheric air, that it displaces.
In which of the following body shapes, the pressure drag is large compared to the friction drag ?
a. Stream line body
b. Two-dimensional body
c. Bluff body
d. None of these
c. Bluff body
Major loss in sudden contraction in pipe flow is due to
a. boundary friction.
b. flow contraction.
c. expansion of flow after sudden contraction.
d. none of these.
b. flow contraction.
Which of the following can be used to create a flow of gas, where no significant compression is required ?
a. Reciprocating compressor
b. Blower
c. Axial flow compressor
d. Centrifugal compressor
b. Blower
The ratio of actual discharge to theoretical discharge through an orifice is equal to
a. Cc . Cv
b. Cc . Cd
c. Cv . Cd
d. Cd/Cv
a. Cc . Cv
Cp/Cv is termed as
a. adiabatic constant
b. Mach number
c. Weber number
d. Prandtl number
a. adiabatic constant
Which of the following valves will incur maximum pressure drop for the same discharge of water?
a. Globe valve
b. Gate valve
c. Needle valve
d. Butterfly valve
c. Needle valve
Pressure drop in a fluidized bed reactor is __________ that in a similar packed bed reactor.
a. less than
b. more than
c. same as
d. none of these
b. more than
In deriving Bernoulli’s equation, fluid is assumed to be
a. incompressible, frictionless, steady, along a streamline.
b. uniform, steady, incompressible, along a streamline.
c. steady, density being pressure dependent, frictionless.
d. none of these.
a. incompressible, frictionless, steady, along a streamline.
Unit of mass velocity is
a. kg/hr
b. kg/m^2. hr
c. kg/m^2
d. kg/m^3. hr
b. kg/m^2. hr
With increase in molecular weight of the gas, the head developed by a
centrifugal compressor will
a. decrease
b. increase
c. remain same
d. unpredictable
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).
a. H
b. 12.6 H
c. 13.6 H
d. 14.6
b. 12.6 H
The boundary layer thickness at a given section along a flat plate __________ with increasing Reynold’s number.
a. increases
b. decreases
c. remains same
d. may increase or decrease
b. decreases
Low specific speed of a pump implies that, it is a/an __________ pump.
a. axial flow
b. centrifugal
c. mixed flow
d. none of these
b. centrifugal
For pumping slurry, one can use a __________ pump.
a. reciprocating
b. diaphragm
c. centrifugal
d. pneumatic
b. diaphragm
- Bernoulli’s equation describes the
a. mechanical energy balance in potential flow.
b. kinetic energy balance in laminar flow.
c. mechanical energy balance in turbulent flow.
d. mechanical energy balance in boundary layer.
Which law/principle of solid mechanics is similar/equivalent to Newton’s law of viscosity in fluid mechanics ?
a. Archimedes principle.
b. Newton’s second law of motion.
c. Hooke’s law.
d. Newton’s third law of motion.
c. Hooke’s law.
When larger particles e.g., grains are subjected to fluidization, the corresponding bed produced is termed as the __________ bed.
a. spouted
b. sluggish
c. boiling
d. teeter
a. spouted
Minimum fluidisation velocity for a specific system depends upon the
a. particle size.
b. Fluid viscosity.
C. density of both the particle & the fluid.
d. all (a), (b) and (c).
d. all (a), (b) and (c).
Potential flow is characterised by the
a. irrotational and frictionless flow.
b. irrotational and frictional flow.
c. one in which dissipation of mechanical energy into heat occurs.
d. formation of eddies within the stream.
a. irrotational and frictionless flow.
For the production of very high vacuum, a __________ pump is normally used.
a. diffusion
b. centrifugal
c. jet ejector
d. piston
a. diffusion
In parallel pipe problems, the
a. head loss is the same through each pipe.
b. discharge is the same through all the pipes.
c. total head loss is equal to the sum of the head losses through each pipe.
d. none of these.
a. head loss is the same through each pipe.
- Fluid flow through a packed bed is represented by the __________ equation.
a. Fanning’s
b. Ergun’s
c. Hagen-Poiseuille’s
d. none of these
b. Ergun’s
