Fluid Mechanics for Chemical Quiz 3

1 / 50

Co-efficient of velocity is _____ the coefficient of discharge?

Less than

Not related to

Equal to

More than

2 / 50

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

Flow of liquid during operation of the pump

Discharge pressure

All A., B. and C.

3 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Require less space

All A., B. and C.

Have lower operating costs

Have quieter operation

4 / 50

Cd is always _______ Cc?

Either more or less than

Equal to

Greater than

Less than

5 / 50

Centre of pressure of a plane surface of arbitrary shape immersed vertically in a static mass of fluid_________?

Lies above the centroid of the plane surface

Is independent of the specific weight of the fluid

Is different for different fluids

Is at the centroid of the plane surface

6 / 50

Choose the correct set of dimensions of viscosity that are equivalent (where, F, M, L, T are dimensions for force, mass, length and time respectively) ?

ML-1T-3, F-1L2T

FLT, ML-1T-1

F-1L2T-1, MLT-3

FL-2T, ML-1T-1

7 / 50

Diaphragm valves are used for handling ________ fluids?

Non-Newtonian

Solid suspended

Corrosive

Viscous

8 / 50

Centrifugal pump can?t be used to pump _______?

Moderately viscous vegetable oil used in soap industry

Thick molten soap at 80?C

Molten sodium (used as a coolant in Fast Breeder Reactor)

None of the above

9 / 50

Brownian movement is prominent in the particle size range of ______ microns in case of settling of a particle in a fluid?

100 to 1000

2 to 3

200 to 300

0.01 to 0.10

10 / 50

Curve III in the bellow diagram represents a/an_________?

Dilatent fluid

Pseudo plastic fluid

Ideal plastic

None of these

11 / 50

Check in a centrifugal pump is_________?

Provided in the discharge line

Generally a globe valve

Provided to prevent liquid from backing up through the pump when the pump is turned off or accidently stops running

All A., B. and C.

12 / 50

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

1/d

1/?

13 / 50

Differential manometer measures the_____?

Pressure difference

Absolute pressure

Pressure gradient

Gauge pressure

14 / 50

Disc compensators are provided in large diameter fuel gas carrying pipelines to__________?

Account for the pressure variation side the pipeline

Make the pipe joint leak-proof

Account for contraction/expansion of pipe due to temperature changes of the surroundings

Keep the pipe in proper orientation

15 / 50

Dimension of absolute viscosity is__________?

MLT-1

ML-1T-1

ML-1T

MLT

16 / 50

Cavitation in a pump creates so many undesirable effects. Out of the following, which is not an undesirable effect created by cavitation ?

Develops noise

Increase in thrust

Decrease in effect

Develops high pressure

17 / 50

Buoyant force___________?

For non-symmetrical bodies is not vertical

Depends on the depth of the submergence of the floating body

Depends on the weight of the floating body

None of these

18 / 50

Creeping flow around a sphere is defined, when particle Reynolds number is_____?

< 500

< 2100

> 2.5

< 0.1

19 / 50

Cavitation occurs in a centrifugal pump when the suction pressure is_________?

Equal to the developed head

Greater than the vapour pressure of the liquid at that temperature

Equal to the vapour pressure

Less than the vapour pressure of the liquid at that temperature

20 / 50

Cd for the orifice plate varies from _____?

0.2 to 0.3

0.02 to 0.03

0.58 to 0.8

0.93 to 0.98

21 / 50

Cocks are used to control _____?

Solids

Any liquid

Water

None of these

22 / 50

Deformation drag, which is caused by widespread deformation of fluid around the immersed body______?

Is primarily a friction drag

Depends mainly on cross-sectional shape

Occurs when NRe is very small

Is independent of body length

23 / 50

Co-efficient of discharge (Cd) is defined as actual discharge/theoretical discharge and is equal to Cc . Cv; where Cc = Co-efficient of contraction and Cv = co-efficient of velocity. Cd of an orifice is usually about___________?

0.82

0.62

0.42

0.98

24 / 50

Cavitation in a centrifugal pump can be avoided by keeping the___________?

Inlet pressure low

Outlet pressure high

Inlet pressure high

Outlet pressure low

25 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Deliver fluid with pulsating/fluctuating discharge

Run at a lower speed for the same discharge

Do not need priming

Can be run with discharge line valve closed for a short interval

26 / 50

Design of the casing of centrifugal pump should be such as to minimise the_________?

None of these

Loss of static head

Back flow through impeller

Loss of kinetic head

27 / 50

Check valve is used for _________ flow?

Unidirectional

Very precise control of

Multidirectional

None of these

28 / 50

Capacity of a rotary gear pump can be varied by___________?

All A., B. and C.

Bleeding air into suction

Bypassing liquid from the suction or discharge line

Changing the speed of rotation

29 / 50

Capacity of a hydraulic accumulator is defined in terms of maximum_______?

Amount of energy stored

Rate of falling of ram

Volume available in the cylinder

Flow rate through accumulator

30 / 50

Boundary layer separation occurs when the______?

Valve is closed in a pipeline

Velocity of sound is reached

Cross-section of the channel is reduced

Pressure reaches a minimum

31 / 50

Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of constant density at a particular discharge capacity. With decrease in the capacity of the pump, the ________ decreases?

All A., B. and C.

NPSH required

Head of the liquid pumped

BHP required by the pump

32 / 50

Choose the set of pressure intensities that are equivalent ?

10 psi, 19.7 ft. of water, 5.3 inches of Hg

10 psi, 19.7 ft. of water, 23.3 inches of Hg

4.33 psi, 10 ft. of water, 20.7 inches of Hg

4.33 psi, 10 ft. of water, 8.83 inches of Hg

33 / 50

Choking in case of pipe flow means that a_____?

None of these

Specified mass flow rate cannot be achieved

Restriction in flow cross-section area occurs

Valve is closed in the line

34 / 50

Critical velocity in a pipe flow__________?

Increases as fluid viscosity increases

Increases as pipe diameter increases

Independent of fluid density

None of these

35 / 50

Cp/Cv is termed as___________?

Mach number

Prandtl number

Weber number

Adiabatic constant

36 / 50

Dimension of surface tension is (where, F = force, L = length) ?

F-1. L

F-2. L

F.L-2

FL-1

37 / 50

Centre of pressure in an immersed body is _______ the centre of gravity?

Below

Above

Either above or below; depends on the liquid density

38 / 50

Cavitation can be prevented by_________?

Maintaining suction head lower than the vapour pressure

Suitably designing the pump

Maintaining suction head = developed head

Maintaining the suction head sufficiently greater than the vapour pressure

39 / 50

Buckingham-? theorem states that in any physical problem including ?n? quantities having ?m? dimensions, the quantities can be arranged into ______ independent dimensionless parameters?

n-m

n/m

40 / 50

Check valves are used________?

In bends

For controlling water flow

For unidirectional flow

At high pressure

41 / 50

Dimension of kinematic viscosity is_______?

L2T-1

L2T

L2T-2

MLT-1

42 / 50

Colebrook equation for friction factor in turbulent flow is given by, f-0.5 = -4 loge [(?/D) + (1.26/NRe ?F). It reduces to Nikuradse equation for a value of (?/D) equal to ___________?

0.5

43 / 50

Centrifugal pump is normally classified on the basis of the_________?

Impeller blade angle

Number of blades in impeller

Type of casing

rpm

44 / 50

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

d2/3

d1/3

45 / 50

Dean number is concerned with the______?

Fluid-particle interaction

Psychrometry

Fluid flow through helical pipes

Power consumption in agitated vessels

46 / 50

Consider two pipes of same length and diameter through which water is passed at the same velocity. The friction factor for rough pipe is f1 and that for smooth pipe is f2. Pick out the correct statement ?

f1 > f2

f1 < f2

Data not sufficient to relate f1 & f2

f1 = f2

47 / 50

Differential manometer measures the______?

Pressure difference between two points

None of these

Sub-atmospheric pressure

Atmospheric pressure

48 / 50

Diaphragm pumps are used to transport__________?

Fluids

Solids

Liquids

Slurries

49 / 50

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

d2/3

d4/5

d1/3

50 / 50

Capillary tube method of viscosity measurement is based on the _________?

Navier-stokes equation

Stoke?s law

Hagen-Poiseuille?s equation

None of these

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