Fluid Mechanics for Chemical Quiz 3

1 / 50

Check valves are used________?

For unidirectional flow

In bends

For controlling water flow

At high pressure

2 / 50

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

Stoke?s law

Navier-stokes equation

None of these

Hagen-Poiseuille?s equation

3 / 50

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

Is different for different fluids

Is independent of the specific weight of the fluid

Is at the centroid of the plane surface

Lies above the centroid of the plane surface

4 / 50

Centrifugal pump is normally classified on the basis of the_________?

Number of blades in impeller

Impeller blade angle

rpm

Type of casing

5 / 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

6 / 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

7 / 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

Discharge pressure

Flow of liquid during operation of the pump

All A., B. and C.

8 / 50

Centrifugal pump can?t be used to pump _______?

None of the above

Thick molten soap at 80?C

Moderately viscous vegetable oil used in soap industry

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

9 / 50

Dimension of kinematic viscosity is_______?

L2T-2

L2T-1

MLT-1

L2T

10 / 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

FL-2T, ML-1T-1

FLT, ML-1T-1

F-1L2T-1, MLT-3

11 / 50

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

Develops high pressure

Decrease in effect

Develops noise

Increase in thrust

12 / 50

Diaphragm pumps are used to transport__________?

Liquids

Slurries

Fluids

Solids

13 / 50

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

200 to 300

0.01 to 0.10

100 to 1000

2 to 3

14 / 50

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

Greater than the vapour pressure of the liquid at that temperature

Equal to the vapour pressure

Equal to the developed head

Less than the vapour pressure of the liquid at that temperature

15 / 50

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

Less than

More than

Not related to

Equal to

16 / 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?

BHP required by the pump

NPSH required

All A., B. and C.

Head of the liquid pumped

17 / 50

Curve III in the bellow diagram represents a/an_________?

Dilatent fluid

None of these

Ideal plastic

Pseudo plastic fluid

18 / 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___________?

0.42

0.62

0.82

0.98

19 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

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

Run at a lower speed for the same discharge

Do not need priming

Deliver fluid with pulsating/fluctuating discharge

20 / 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

Provided in the discharge line

Generally a globe valve

All A., B. and C.

21 / 50

Differential manometer measures the______?

None of these

Sub-atmospheric pressure

Pressure difference between two points

Atmospheric pressure

22 / 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/?

23 / 50

Dimension of absolute viscosity is__________?

ML-1T

MLT-1

MLT

ML-1T-1

24 / 50

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

Is independent of body length

Depends mainly on cross-sectional shape

Occurs when NRe is very small

Is primarily a friction drag

25 / 50

Cd is always _______ Cc?

Equal to

Greater than

Less than

Either more or less than

26 / 50

Critical velocity in a pipe flow__________?

Increases as fluid viscosity increases

Increases as pipe diameter increases

Independent of fluid density

None of these

27 / 50

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

Outlet pressure high

Inlet pressure high

Outlet pressure low

Inlet pressure low

28 / 50

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

d1/3

d2/3

29 / 50

Cd for the orifice plate varies from _____?

0.2 to 0.3

0.02 to 0.03

0.93 to 0.98

0.58 to 0.8

30 / 50

Choose the set of pressure intensities that are equivalent ?

4.33 psi, 10 ft. of water, 8.83 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

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

31 / 50

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

Loss of kinetic head

Loss of static head

Back flow through impeller

None of these

32 / 50

Cp/Cv is termed as___________?

Mach number

Adiabatic constant

Weber number

Prandtl number

33 / 50

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

Either above or below; depends on the liquid density

Above

Below

34 / 50

Cocks are used to control _____?

Water

Any liquid

Solids

None of these

35 / 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

36 / 50

Boundary layer separation occurs when the______?

Valve is closed in a pipeline

Velocity of sound is reached

Pressure reaches a minimum

Cross-section of the channel is reduced

37 / 50

Buoyant force___________?

Depends on the weight of the floating body

None of these

For non-symmetrical bodies is not vertical

Depends on the depth of the submergence of the floating body

38 / 50

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

Amount of energy stored

Flow rate through accumulator

Volume available in the cylinder

Rate of falling of ram

39 / 50

Diaphragm valves are used for handling ________ fluids?

Viscous

Solid suspended

Non-Newtonian

Corrosive

40 / 50

Check valve is used for _________ flow?

Unidirectional

None of these

Very precise control of

Multidirectional

41 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Require less space

Have quieter operation

Have lower operating costs

All A., B. and C.

42 / 50

Differential manometer measures the_____?

Gauge pressure

Pressure gradient

Absolute pressure

Pressure difference

43 / 50

Dean number is concerned with the______?

Fluid-particle interaction

Psychrometry

Fluid flow through helical pipes

Power consumption in agitated vessels

44 / 50

Choking in case of pipe flow means that a_____?

Restriction in flow cross-section area occurs

Specified mass flow rate cannot be achieved

Valve is closed in the line

None of these

45 / 50

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

Account for the pressure variation side the pipeline

Keep the pipe in proper orientation

Make the pipe joint leak-proof

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

46 / 50

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

< 0.1

< 500

> 2.5

< 2100

47 / 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

f1 < f2

Data not sufficient to relate f1 & f2

48 / 50

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

F.L-2

F-2. L

F-1. L

FL-1

49 / 50

Capacity of a rotary gear pump can be varied by___________?

Bypassing liquid from the suction or discharge line

Bleeding air into suction

Changing the speed of rotation

All A., B. and C.

50 / 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

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