Fluid Mechanics for Chemical Quiz 3

1 / 50

Differential manometer measures the_____?

Pressure difference

Pressure gradient

Absolute pressure

Gauge pressure

2 / 50

Dean number is concerned with the______?

Fluid-particle interaction

Power consumption in agitated vessels

Fluid flow through helical pipes

Psychrometry

3 / 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.

4 / 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

5 / 50

Capacity of a rotary gear pump can be varied by___________?

Bypassing liquid from the suction or discharge line

Changing the speed of rotation

All A., B. and C.

Bleeding air into suction

6 / 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

7 / 50

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

Make the pipe joint leak-proof

Keep the pipe in proper orientation

Account for the pressure variation side the pipeline

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

8 / 50

Cd is always _______ Cc?

Either more or less than

Equal to

Greater than

Less than

9 / 50

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

d2/3

d1/3

10 / 50

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

Depends mainly on cross-sectional shape

Is primarily a friction drag

Is independent of body length

Occurs when NRe is very small

11 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Require less space

Have lower operating costs

All A., B. and C.

Have quieter operation

12 / 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

All A., B. and C.

NPSH required

Head of the liquid pumped

13 / 50

Dimension of absolute viscosity is__________?

ML-1T-1

ML-1T

MLT-1

MLT

14 / 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

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

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

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

Diaphragm pumps are used to transport__________?

Solids

Slurries

Liquids

Fluids

17 / 50

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

Inlet pressure low

Outlet pressure high

Outlet pressure low

Inlet pressure high

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___________?

0.82

0.62

0.98

0.42

19 / 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 ?

Data not sufficient to relate f1 & f2

f1 = f2

f1 > f2

f1 < f2

20 / 50

Cocks are used to control _____?

None of these

Any liquid

Solids

Water

21 / 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

All A., B. and C.

Flow of liquid during operation of the pump

22 / 50

Choking in case of pipe flow means that a_____?

Valve is closed in the line

Specified mass flow rate cannot be achieved

Restriction in flow cross-section area occurs

None of these

23 / 50

Differential manometer measures the______?

Pressure difference between two points

None of these

Sub-atmospheric pressure

Atmospheric pressure

24 / 50

Critical velocity in a pipe flow__________?

Independent of fluid density

Increases as pipe diameter increases

None of these

Increases as fluid viscosity increases

25 / 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

26 / 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

27 / 50

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

FL-1

F-1. L

F-2. L

F.L-2

28 / 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 at the centroid of the plane surface

Lies above the centroid of the plane surface

Is different for different fluids

29 / 50

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

Navier-stokes equation

Stoke?s law

None of these

Hagen-Poiseuille?s equation

30 / 50

Buoyant force___________?

Depends on the weight of the floating body

For non-symmetrical bodies is not vertical

None of these

Depends on the depth of the submergence of the floating body

31 / 50

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

Either above or below; depends on the liquid density

Below

Above

32 / 50

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

< 2100

< 500

< 0.1

> 2.5

33 / 50

Centrifugal pump is normally classified on the basis of the_________?

Type of casing

Number of blades in impeller

Impeller blade angle

rpm

34 / 50

Dimension of kinematic viscosity is_______?

L2T

L2T-2

MLT-1

L2T-1

35 / 50

Cp/Cv is termed as___________?

Adiabatic constant

Weber number

Mach number

Prandtl number

36 / 50

Cavitation can be prevented by_________?

Maintaining suction head lower than the vapour pressure

Maintaining suction head = developed head

Suitably designing the pump

Maintaining the suction head sufficiently greater than the vapour pressure

37 / 50

Boundary layer separation occurs when the______?

Valve is closed in a pipeline

Pressure reaches a minimum

Cross-section of the channel is reduced

Velocity of sound is reached

38 / 50

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

Loss of kinetic head

Loss of static head

None of these

Back flow through impeller

39 / 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) ?

F-1L2T-1, MLT-3

FLT, ML-1T-1

FL-2T, ML-1T-1

ML-1T-3, F-1L2T

40 / 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

Deliver fluid with pulsating/fluctuating discharge

Do not need priming

41 / 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

0.01 to 0.10

200 to 300

2 to 3

42 / 50

Cd for the orifice plate varies from _____?

0.2 to 0.3

0.58 to 0.8

0.02 to 0.03

0.93 to 0.98

43 / 50

Diaphragm valves are used for handling ________ fluids?

Corrosive

Non-Newtonian

Viscous

Solid suspended

44 / 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 high pressure

Develops noise

Increase in thrust

45 / 50

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

Rate of falling of ram

Volume available in the cylinder

Flow rate through accumulator

Amount of energy stored

46 / 50

Curve III in the bellow diagram represents a/an_________?

None of these

Dilatent fluid

Pseudo plastic fluid

Ideal plastic

47 / 50

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

Less than

Equal to

More than

Not related to

48 / 50

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

Equal to the developed head

Equal to the vapour pressure

Greater than the vapour pressure of the liquid at that temperature

Less than the vapour pressure of the liquid at that temperature

49 / 50

Check valves are used________?

At high pressure

For controlling water flow

In bends

For unidirectional flow

50 / 50

Check valve is used for _________ flow?

Multidirectional

Very precise control of

Unidirectional

None of these

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