Fluid Mechanics for Chemical Quiz 3

1 / 50

Dimension of absolute viscosity is__________?

ML-1T

ML-1T-1

MLT

MLT-1

2 / 50

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

Back flow through impeller

Loss of static head

None of these

Loss of kinetic head

3 / 50

Centrifugal pump is normally classified on the basis of the_________?

Number of blades in impeller

rpm

Impeller blade angle

Type of casing

4 / 50

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

Decrease in effect

Develops noise

Increase in thrust

Develops high pressure

5 / 50

Choking in case of pipe flow means that a_____?

Valve is closed in the line

None of these

Restriction in flow cross-section area occurs

Specified mass flow rate cannot be achieved

6 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Deliver fluid with pulsating/fluctuating discharge

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

Do not need priming

Run at a lower speed for the same discharge

7 / 50

Differential manometer measures the______?

None of these

Sub-atmospheric pressure

Atmospheric pressure

Pressure difference between two points

8 / 50

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

F.L-2

F-2. L

FL-1

F-1. L

9 / 50

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

1/?

1/d

10 / 50

Check valves are used________?

In bends

For controlling water flow

At high pressure

For unidirectional flow

11 / 50

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

> 2.5

< 0.1

< 2100

< 500

12 / 50

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

Keep the pipe in proper orientation

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

13 / 50

Choose the set of pressure intensities that are equivalent ?

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

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

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

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

14 / 50

Curve III in the bellow diagram represents a/an_________?

Dilatent fluid

Pseudo plastic fluid

Ideal plastic

None of these

15 / 50

Capacity of a rotary gear pump can be varied by___________?

All A., B. and C.

Changing the speed of rotation

Bypassing liquid from the suction or discharge line

Bleeding air into suction

16 / 50

Cd is always _______ Cc?

Less than

Greater than

Either more or less than

Equal to

17 / 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___________?

0.98

0.82

0.62

0.42

18 / 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

19 / 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?

NPSH required

BHP required by the pump

Head of the liquid pumped

All A., B. and C.

20 / 50

Differential manometer measures the_____?

Pressure difference

Pressure gradient

Absolute pressure

Gauge pressure

21 / 50

Diaphragm pumps are used to transport__________?

Solids

Liquids

Slurries

Fluids

22 / 50

Check valve is used for _________ flow?

Multidirectional

Unidirectional

None of these

Very precise control of

23 / 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

24 / 50

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

Is independent of the specific weight of the fluid

Is different for different fluids

Lies above the centroid of the plane surface

Is at the centroid of the plane surface

25 / 50

Cocks are used to control _____?

None of these

Water

Solids

Any liquid

26 / 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) ?

FLT, ML-1T-1

ML-1T-3, F-1L2T

F-1L2T-1, MLT-3

FL-2T, ML-1T-1

27 / 50

Dimension of kinematic viscosity is_______?

L2T

L2T-1

L2T-2

MLT-1

28 / 50

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

Hagen-Poiseuille?s equation

None of these

Stoke?s law

Navier-stokes equation

29 / 50

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

Flow of liquid during operation of the pump

Back flow of fluid in the event of stoppage of pump

Discharge pressure

All A., B. and C.

30 / 50

Diaphragm valves are used for handling ________ fluids?

Non-Newtonian

Corrosive

Solid suspended

Viscous

31 / 50

Centrifugal pump can?t be used to pump _______?

Moderately viscous vegetable oil used in soap industry

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

None of the above

Thick molten soap at 80?C

32 / 50

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

Equal to the developed head

Less than the vapour pressure of the liquid at that temperature

Equal to the vapour pressure

Greater than the vapour pressure of the liquid at that temperature

33 / 50

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

Either above or below; depends on the liquid density

Below

Above

34 / 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

35 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Require less space

All A., B. and C.

Have lower operating costs

Have quieter operation

36 / 50

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

d2/3

d1/3

37 / 50

Check in a centrifugal pump is_________?

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.

Generally a globe valve

Provided in the discharge line

38 / 50

Cd for the orifice plate varies from _____?

0.58 to 0.8

0.93 to 0.98

0.02 to 0.03

0.2 to 0.3

39 / 50

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

d4/5

d1/3

d2/3

40 / 50

Critical velocity in a pipe flow__________?

Increases as fluid viscosity increases

Increases as pipe diameter increases

None of these

Independent of fluid density

41 / 50

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

Depends mainly on cross-sectional shape

Occurs when NRe is very small

Is independent of body length

Is primarily a friction drag

42 / 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

200 to 300

2 to 3

0.01 to 0.10

43 / 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

44 / 50

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

Equal to

More than

Less than

Not related to

45 / 50

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

Outlet pressure high

Outlet pressure low

Inlet pressure high

Inlet pressure low

46 / 50

Dean number is concerned with the______?

Psychrometry

Fluid-particle interaction

Fluid flow through helical pipes

Power consumption in agitated vessels

47 / 50

Cp/Cv is termed as___________?

Weber number

Prandtl number

Mach number

Adiabatic constant

48 / 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

49 / 50

Buoyant force___________?

Depends on the weight of the floating body

None of these

Depends on the depth of the submergence of the floating body

For non-symmetrical bodies is not vertical

50 / 50

Cavitation can be prevented by_________?

Suitably designing the pump

Maintaining the suction head sufficiently greater than the vapour pressure

Maintaining suction head = developed head

Maintaining suction head lower than the vapour pressure

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