Fluid Mechanics for Chemical Quiz 3

1 / 50

Check valve is used for _________ flow?

None of these

Multidirectional

Very precise control of

Unidirectional

2 / 50

Dean number is concerned with the______?

Power consumption in agitated vessels

Fluid flow through helical pipes

Psychrometry

Fluid-particle interaction

3 / 50

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

Inlet pressure low

Inlet pressure high

Outlet pressure high

Outlet pressure low

4 / 50

Buoyant force___________?

Depends on the weight of the floating body

Depends on the depth of the submergence of the floating body

None of these

For non-symmetrical bodies is not vertical

5 / 50

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

F.L-2

F-2. L

F-1. L

FL-1

6 / 50

Cocks are used to control _____?

Water

Solids

None of these

Any liquid

7 / 50

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

Navier-stokes equation

Hagen-Poiseuille?s equation

Stoke?s law

None of these

8 / 50

Centrifugal pump is normally classified on the basis of the_________?

rpm

Impeller blade angle

Number of blades in impeller

Type of casing

9 / 50

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

Loss of kinetic head

Back flow through impeller

Loss of static head

None of these

10 / 50

Curve III in the bellow diagram represents a/an_________?

None of these

Pseudo plastic fluid

Ideal plastic

Dilatent fluid

11 / 50

Differential manometer measures the______?

Sub-atmospheric pressure

Pressure difference between two points

Atmospheric pressure

None of these

12 / 50

Choking in case of pipe flow means that a_____?

Specified mass flow rate cannot be achieved

None of these

Restriction in flow cross-section area occurs

Valve is closed in the line

13 / 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

Discharge pressure

All A., B. and C.

Back flow of fluid in the event of stoppage of pump

14 / 50

Boundary layer separation occurs when the______?

Valve is closed in a pipeline

Pressure reaches a minimum

Velocity of sound is reached

Cross-section of the channel is reduced

15 / 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

16 / 50

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

Either above or below; depends on the liquid density

Above

Below

17 / 50

Dimension of absolute viscosity is__________?

MLT-1

ML-1T

ML-1T-1

MLT

18 / 50

Cd is always _______ Cc?

Equal to

Less than

Greater than

Either more or less than

19 / 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

20 / 50

Centrifugal pump can?t be used to pump _______?

None of the above

Moderately viscous vegetable oil used in soap industry

Thick molten soap at 80?C

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

21 / 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

22 / 50

Check valves are used________?

For unidirectional flow

At high pressure

In bends

For controlling water flow

23 / 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

24 / 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

25 / 50

Check in a centrifugal pump is_________?

Generally a globe valve

Provided in the discharge line

All A., B. and C.

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

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

F-1L2T-1, MLT-3

ML-1T-3, F-1L2T

FL-2T, ML-1T-1

27 / 50

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

Flow rate through accumulator

Volume available in the cylinder

Rate of falling of ram

Amount of energy stored

28 / 50

Cd for the orifice plate varies from _____?

0.93 to 0.98

0.58 to 0.8

0.2 to 0.3

0.02 to 0.03

29 / 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

2 to 3

100 to 1000

0.01 to 0.10

30 / 50

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

Depends mainly on cross-sectional shape

Is independent of body length

Occurs when NRe is very small

Is primarily a friction drag

31 / 50

Differential manometer measures the_____?

Gauge pressure

Pressure gradient

Absolute pressure

Pressure difference

32 / 50

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

< 2100

< 0.1

< 500

> 2.5

33 / 50

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

d1/3

d2/3

34 / 50

Choose the set of pressure intensities that are equivalent ?

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

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

35 / 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

0.42

0.82

0.62

36 / 50

Diaphragm valves are used for handling ________ fluids?

Corrosive

Solid suspended

Non-Newtonian

Viscous

37 / 50

Critical velocity in a pipe flow__________?

Increases as pipe diameter increases

Increases as fluid viscosity increases

None of these

Independent of fluid density

38 / 50

Cp/Cv is termed as___________?

Weber number

Prandtl number

Mach number

Adiabatic constant

39 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Require less space

Have quieter operation

Have lower operating costs

All A., B. and C.

40 / 50

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

Equal to

Not related to

Less than

More than

41 / 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

42 / 50

Capacity of a rotary gear pump can be varied by___________?

All A., B. and C.

Bypassing liquid from the suction or discharge line

Changing the speed of rotation

Bleeding air into suction

43 / 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

44 / 50

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

d1/3

d2/3

d4/5

45 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

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

Do not need priming

Deliver fluid with pulsating/fluctuating discharge

Run at a lower speed for the same discharge

46 / 50

Diaphragm pumps are used to transport__________?

Solids

Liquids

Slurries

Fluids

47 / 50

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

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

Keep the pipe in proper orientation

Account for the pressure variation side the pipeline

Make the pipe joint leak-proof

48 / 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?

Head of the liquid pumped

NPSH required

All A., B. and C.

BHP required by the pump

49 / 50

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

Is at the centroid of the plane surface

Is different for different fluids

Lies above the centroid of the plane surface

Is independent of the specific weight of the fluid

50 / 50

Dimension of kinematic viscosity is_______?

MLT-1

L2T-2

L2T-1

L2T

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