Fluid Mechanics for Chemical Quiz 3

1 / 50

Cd is always _______ Cc?

Equal to

Less than

Greater than

Either more or less than

2 / 50

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

< 0.1

> 2.5

< 2100

< 500

3 / 50

Cavitation can be prevented by_________?

Maintaining suction head = developed head

Maintaining suction head lower than the vapour pressure

Suitably designing the pump

Maintaining the suction head sufficiently greater than the vapour pressure

4 / 50

Boundary layer separation occurs when the______?

Pressure reaches a minimum

Cross-section of the channel is reduced

Valve is closed in a pipeline

Velocity of sound is reached

5 / 50

Check valve is used for _________ flow?

Very precise control of

Multidirectional

Unidirectional

None of these

6 / 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

7 / 50

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

F-2. L

FL-1

F.L-2

F-1. L

8 / 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

9 / 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.

Head of the liquid pumped

NPSH required

10 / 50

Capacity of a rotary gear pump can be varied by___________?

Changing the speed of rotation

Bypassing liquid from the suction or discharge line

Bleeding air into suction

All A., B. and C.

11 / 50

Differential manometer measures the______?

Sub-atmospheric pressure

Atmospheric pressure

None of these

Pressure difference between two points

12 / 50

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

Outlet pressure high

Inlet pressure low

Outlet pressure low

Inlet pressure high

13 / 50

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

Hagen-Poiseuille?s equation

Stoke?s law

Navier-stokes equation

None of these

14 / 50

Critical velocity in a pipe flow__________?

None of these

Independent of fluid density

Increases as pipe diameter increases

Increases as fluid viscosity increases

15 / 50

Centrifugal pump is normally classified on the basis of the_________?

Type of casing

Number of blades in impeller

rpm

Impeller blade angle

16 / 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.

17 / 50

Cocks are used to control _____?

Any liquid

Solids

None of these

Water

18 / 50

Differential manometer measures the_____?

Absolute pressure

Pressure difference

Pressure gradient

Gauge pressure

19 / 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___________?

0.62

0.98

0.82

0.42

20 / 50

Dimension of absolute viscosity is__________?

ML-1T

ML-1T-1

MLT-1

MLT

21 / 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

100 to 1000

2 to 3

0.01 to 0.10

22 / 50

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

d1/3

d2/3

23 / 50

Centrifugal pump can?t be used to pump _______?

None of the above

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

Thick molten soap at 80?C

Moderately viscous vegetable oil used in soap industry

24 / 50

Check valves are used________?

For controlling water flow

For unidirectional flow

At high pressure

In bends

25 / 50

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

All A., B. and C.

Back flow of fluid in the event of stoppage of pump

Discharge pressure

Flow of liquid during operation of the pump

26 / 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

27 / 50

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

Either above or below; depends on the liquid density

Below

Above

28 / 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

Run at a lower speed for the same discharge

Do not need priming

29 / 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

30 / 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) ?

FL-2T, ML-1T-1

FLT, ML-1T-1

ML-1T-3, F-1L2T

F-1L2T-1, MLT-3

31 / 50

Curve III in the bellow diagram represents a/an_________?

Dilatent fluid

None of these

Ideal plastic

Pseudo plastic fluid

32 / 50

Choose the set of pressure intensities that are equivalent ?

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

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, 23.3 inches of Hg

33 / 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

34 / 50

Diaphragm valves are used for handling ________ fluids?

Viscous

Corrosive

Non-Newtonian

Solid suspended

35 / 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

Greater than the vapour pressure of the liquid at that temperature

Equal to the vapour pressure

36 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Have lower operating costs

Have quieter operation

Require less space

All A., B. and C.

37 / 50

Dean number is concerned with the______?

Psychrometry

Fluid-particle interaction

Fluid flow through helical pipes

Power consumption in agitated vessels

38 / 50

Cp/Cv is termed as___________?

Adiabatic constant

Weber number

Mach number

Prandtl number

39 / 50

Choking in case of pipe flow means that a_____?

Specified mass flow rate cannot be achieved

Valve is closed in the line

None of these

Restriction in flow cross-section area occurs

40 / 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

41 / 50

Diaphragm pumps are used to transport__________?

Fluids

Slurries

Solids

Liquids

42 / 50

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

Equal to

Less than

Not related to

More than

43 / 50

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

d4/5

d2/3

d1/3

44 / 50

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

Back flow through impeller

Loss of kinetic head

Loss of static head

None of these

45 / 50

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

Is independent of body length

Is primarily a friction drag

Occurs when NRe is very small

Depends mainly on cross-sectional shape

46 / 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

Lies above the centroid of the plane surface

Is at the centroid of the plane surface

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 ?

Data not sufficient to relate f1 & f2

f1 > f2

f1 < f2

f1 = f2

48 / 50

Buoyant force___________?

None of these

For non-symmetrical bodies is not vertical

Depends on the weight of the floating body

Depends on the depth of the submergence of the floating body

49 / 50

Dimension of kinematic viscosity is_______?

MLT-1

L2T

L2T-2

L2T-1

50 / 50

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

Keep the pipe in proper orientation

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

Account for the pressure variation side the pipeline

Make the pipe joint leak-proof

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