Q.1

A mixed flow centrifugal pump

  • employs such an impeller, through which the flow is a combination of radial & axial flow.
  • mixes the two fluids before pumping them.
  • pumps the two fluids separately and then mixes them.
  • employs impellers in both the radial & axial directions.
Q.2

Most of the centrifugal pumps used in chemical plants are usually __________ driven.

  • steam
  • diesel engine
  • electric motor
  • gas turbine
Q.3

What is the pipe called which lifts water from a reservoir to a greater height than the initial level in the supply reservoir ?

  • Penstock
  • Siphon
  • Tunnel
  • Pressure pipeline
Q.4

Capillary rise of mercury in a small diameter tube is proportional to (where, d = diameter of the tube, σ = surface tension of mercury)

  • d
  • 1/d
  • σ
  • l/σ
Q.5

A 0.5 m high bed made up of a 1 mm dia glass sphere (densitykg/m3 ) is to be fluidised by water (densitykg/m3 ). If at the point of incipient fluidisation, the bed voidage is 40%, the pressure drop across the bed is

  • 4.4 KPa
  • 2.94 KPa
  • 3.7 KPa
  • none of these
Q.6

A rotameter works on the principle of __________ pressure drop.

  • constant
  • variable
  • both (a) & (b)
  • neither (a) nor (b)
Q.7

Differential manometer measures the

  • atmospheric pressure.
  • sub-atmospheric pressure.
  • pressure difference between two points.
  • none of these.
Q.8

Capillary rise of mercury in a small diameter tube is proportional to (where, d = diameter of the tube, σ = surface tension of mercury)

  • d
  • 1/d
  • σ
  • l/σ
Q.9

Which of the following is not an advantage of fluidisation from transfer operation point of view?

  • Intimate contact of the fluid with all parts of the solid particles.
  • Lower fluid pumping power requirement.
  • Minimisation of temperature variation.
  • Prevention of particle seggregation.
Q.10

Potential flow is the flow of

  • compressible fluids with shear.
  • compressible fluids with no shear.
  • incompressible fluids with shear.
  • incompressible fluids with no shear.
Q.11

The Mach number for hypersonic flow of compressible fluid is

  • 1
  • > 1
  • > 4
  • < 2
Q.12

Small pressure differences in liquids is measured using a/an

  • U-tube manometer.
  • inclined tube manometer.
  • pitot tube.
  • none of these.
Q.13

For pipes that must be broken at intervals for maintenance, the connector used should be a/an

  • union
  • tee
  • reducer
  • elbow
Q.14

Ratio of pressure and inertia force gives __________ number.

  • Weber
  • Mach
  • Euler
  • Froude
Q.15

In centrifugal pump operation, the cavitation can be eliminated by maintaining suction pressure __________ the vapor pressure of the liquid at the suction temperature.

  • lower than
  • higher than
  • equal to
  • none of these
Q.16

Check valve provided in the discharge line of a centrifugal pump serves the purpose of controlling the

  • back flow of fluid in the event of stoppage of pump.
  • discharge pressure.
  • flow of liquid during operation of the pump.
  • all (a), (b) and (c).
Q.17

The distribution of shear stress in a stream of fluid in a circular tube is

  • linear with radius for turbulent flow only.
  • linear with radius for laminar flow only.
  • linear with radius for both laminar & turbulent flow.
  • parabolic with radius for both laminar & turbulent flow.
Q.18

Steady uniform flow is represented by flow through a/an

  • long pipe at constant rate.
  • long pipe at decreasing rate.
  • expanding tube at constant rate.
  • none of these.
Q.19

The effect of solid boundary on the fluid flow is confined to the boundary layer, except for fluids

  • having high viscosities.
  • moving at low velocities.
  • both (a) & (b).
  • neither (a) nor (b).
Q.20

For a stable equilibrium of a submerged body (where, G and B are centres of gravity & buoyancy respectively).

  • G is above B
  • B is above G
  • B & coincide
  • none of these
Q.21

Upto what value of 'Mach number', a fluid may be considered as incompressible ?

  • 0.03
  • 0.3
  • 3
  • 10
Q.22

The value of critical Reynolds number for pipe flow is

  • 1300
  • 10,000
  • 100,s000
  • none of these.
Q.23

Boundary layer thickness in turbulent flow over a flat plate increases as(where, d = distance from the leading edge.)

  • d
  • d2/3
  • d4/5
  • d1/3
Q.24

The unit of velocity head is

  • ft-lb/sec
  • ft-lb/ft3
  • ft-lbf/lb
  • ft-lbf/sec.
Q.25

A rectangular surfacex 4', has the lower 3 edge horizontal andbelow a free oil surface (sp. gr. 0.8). The surface inclination iswith the horizontal. The force on one side of the surface is(where, y = specific weight of water)

  • 39.6y
  • 48y
  • 49.2y
  • 58y
Q.26

In a stabilised soap bubble, pressure inside it compared to external pressure is

  • more
  • less
  • same
  • unpredictable
Q.27

The excess of the sum of pressure & velocity heads over the vapor pressure of the liquid at the suction is called the

  • static submergence.
  • net positive suction head (NPSH).
  • cavitation sensitivity.
  • priming.
Q.28

With increase in the ratio of orifice diameter to pipe diameter in case of an orificemeter, the overall pressure loss

  • decreases
  • increases
  • remains constant
  • increases linearly
Q.29

The head developed by a centrifugal pump is largely determined by the

  • power of the pump.
  • nature of the liquid being pumped.
  • angle of the vanes and the speed of the tip of the impeller.
  • vapour pressure of the liquid.
Q.30

Mach number is important in a fluid flow problem, when the inertia and __________ forces predominate.

  • elastic
  • viscous
  • gravity
  • none of these
Q.31

Drag force on the float of a rotameter is(where Q = flow rate of the )

  • ∝Q
  • ∝Q
  • ∝Q2
  • constant
Q.32

The blades of a centrifugal impeller are said to be curved forward, if the __________ of the motion of impeller blades.

  • inlet tip of a blade curves in a direction opposite to that
  • outlet tip of a blade curves in a direction opposite to that
  • inlet tip of a blade is towards the direction
  • outlet tip of a blade is towards the direction
Q.33

The continuity equation of fluid mechanics utilises the principle of conservation of

  • momentum
  • mass
  • energy
  • both (b) & (c)
Q.34

Mass velocity in case of steady flow and through a constant cross-section conduit is independent of the

  • temperature
  • pressure
  • both (a) & (b)
  • neither (a) nor (b)
Q.35

The valve used for very remote and accurate control of fluid is a __________ valve.

  • needle
  • globe
  • gate
  • butterfly
Q.36

Which of the following properties of a fluid is responsible for offering resistance to shear ?

  • Surface tension.
  • Viscosity.
  • Specific gravity.
  • All (a), (b), and (c).
Q.37

Erosion and pits formation on the impeller of a centrifugal pump may be due to

  • cavitation.
  • low speed of impeller.
  • its operation with delivery valve closed for considerable time after starting the pump.
  • off centering of pump with motor.
Q.38

A bed of spherical particles (specific gravity 2.of uniform sizeμm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.Ergun's equation for the above fluid-particle system (in SI units) is given below :
Δ P/L =x 103 VOM + 10.x 106 V2OM (SI units)
If water is to be used as the fluidising medium, the minimum fluidisation velocity, VOM is

  • 12 mm/s
  • 16 mm/s
  • 24 mm/s
  • 28 mm/s
Q.39

The component of acceleration resulting due to unsteady nature of flow is called __________ acceleration.

  • normal
  • local
  • convective
  • tangential
Q.40

Piezometric head is the sum of the __________ heads.

  • elevation & kinetic energy
  • elevation & pressure
  • kinetic energy & pressure
  • none of these
Q.41

The vent valve provided in a liquid handling centrifugal pump is

  • generally a needle valve.
  • used to release any gases that might be vapour locking the pump.
  • helpful in easy removal of samples.
  • all (a), and (b) and (c).
Q.42

Pick out the wrong statement:

  • Greater is the kinematic viscosity of the liquid, greater is the thickness of the boundary layer.
  • Blowers develop a maximum pressure of 2 atmospheres.
  • Friction losses in pipe fittings are generally expressed in terms of velocity heads.
  • Fanning friction factor in case of turbulent flow of liquids in pipe depends upon relative roughness & Reynolds number.
Q.43

Fanning friction factor is equal to(where, fB = Blassius friction factor).

  • fB/4
  • fB/2
  • 4fB
  • 2fB
Q.44

Capillary rise of mercury in a small diameter tube is proportional to (where, d = diameter of the tube, σ = surface tension of mercury)

  • d
  • 1/d
  • σ
  • l/σ
Q.45

For the same terminal conditions and fitting size, the least friction loss is incurred in a/an

  • T-joint
  • union
  • 45° elbow
  • 90°bend
Q.46

A floating/submerged body is always stable, if its centre of gravity

  • lies above its centre of buoyancy.
  • and centre of buoyancy coincide.
  • lies below its centre of buoyancy.
  • lies above its meta centre.
Q.47

Each term of the Bernoulli's equation written in the form, , represents the total energy per unit

  • mass
  • volume
  • specific weight
  • none of these
Q.48

Stoke's law is valid, when the particle Reynolds number is

  • < 1
  • > 1
  • < 5
  • none of these
Q.49

Which of the following is not a dimension-less parameter ?

  • Pressure-co-efficient
  • Froude number
  • Kinematic viscosity
  • Weber number
Q.50

f = 16/NRe, is valid for

  • turbulent flow
  • laminar flow through an open channel
  • steady flow
  • none of these
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