Fluid Mechanics for Chemical Quiz 3

1 / 50

Dimension of absolute viscosity is__________?

MLT

MLT-1

ML-1T-1

ML-1T

2 / 50

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

Outlet pressure low

Inlet pressure high

Inlet pressure low

Outlet pressure high

3 / 50

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

d2/3

d1/3

4 / 50

Check valves are used________?

At high pressure

For controlling water flow

In bends

For unidirectional flow

5 / 50

Cocks are used to control _____?

Solids

Water

None of these

Any liquid

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

Boundary layer separation occurs when the______?

Pressure reaches a minimum

Cross-section of the channel is reduced

Velocity of sound is reached

Valve is closed in a pipeline

8 / 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

2 to 3

200 to 300

0.01 to 0.10

9 / 50

Cavitation can be prevented by_________?

Maintaining the suction head sufficiently greater than the vapour pressure

Suitably designing the pump

Maintaining suction head lower than the vapour pressure

Maintaining suction head = developed head

10 / 50

Cd for the orifice plate varies from _____?

0.02 to 0.03

0.93 to 0.98

0.58 to 0.8

0.2 to 0.3

11 / 50

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

Flow rate through accumulator

Amount of energy stored

Volume available in the cylinder

Rate of falling of ram

12 / 50

Capacity of a rotary gear pump can be varied by___________?

Bypassing liquid from the suction or discharge line

Changing the speed of rotation

Bleeding air into suction

All A., B. and C.

13 / 50

Check valve is used for _________ flow?

Multidirectional

Very precise control of

Unidirectional

None of these

14 / 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

15 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Run at a lower speed for the same discharge

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

Do not need priming

Deliver fluid with pulsating/fluctuating discharge

16 / 50

Diaphragm pumps are used to transport__________?

Liquids

Fluids

Slurries

Solids

17 / 50

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

Is primarily a friction drag

Is independent of body length

Occurs when NRe is very small

Depends mainly on cross-sectional shape

18 / 50

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

> 2.5

< 500

< 0.1

< 2100

19 / 50

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

Equal to the developed head

Greater than the vapour pressure of the liquid at that temperature

Less than the vapour pressure of the liquid at that temperature

Equal to the vapour pressure

20 / 50

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

None of these

Hagen-Poiseuille?s equation

Navier-stokes equation

Stoke?s law

21 / 50

Critical velocity in a pipe flow__________?

Increases as fluid viscosity increases

Increases as pipe diameter increases

Independent of fluid density

None of these

22 / 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

23 / 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

24 / 50

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

None of these

Back flow through impeller

Loss of kinetic head

Loss of static head

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

Check in a centrifugal pump is_________?

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

Generally a globe valve

27 / 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

Increase in thrust

Develops noise

Decrease in effect

28 / 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

F-1L2T-1, MLT-3

FLT, ML-1T-1

ML-1T-3, F-1L2T

29 / 50

Cp/Cv is termed as___________?

Mach number

Adiabatic constant

Prandtl number

Weber number

30 / 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

Is independent of the specific weight of the fluid

Lies above the centroid of the plane surface

31 / 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, 23.3 inches of Hg

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

32 / 50

Curve III in the bellow diagram represents a/an_________?

None of these

Dilatent fluid

Pseudo plastic fluid

Ideal plastic

33 / 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

34 / 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

0.42

0.98

0.62

35 / 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

36 / 50

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

Less than

Equal to

Not related to

More than

37 / 50

Dean number is concerned with the______?

Psychrometry

Fluid-particle interaction

Power consumption in agitated vessels

Fluid flow through helical pipes

38 / 50

Differential manometer measures the_____?

Gauge pressure

Absolute pressure

Pressure difference

Pressure gradient

39 / 50

Centrifugal pump is normally classified on the basis of the_________?

Impeller blade angle

Type of casing

rpm

Number of blades in impeller

40 / 50

Dimension of kinematic viscosity is_______?

L2T-1

L2T

L2T-2

MLT-1

41 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Have lower operating costs

All A., B. and C.

Require less space

Have quieter operation

42 / 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

All A., B. and C.

Flow of liquid during operation of the pump

Discharge pressure

43 / 50

Choking in case of pipe flow means that a_____?

Valve is closed in the line

Specified mass flow rate cannot be achieved

None of these

Restriction in flow cross-section area occurs

44 / 50

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

F-1. L

FL-1

F-2. L

F.L-2

45 / 50

Buoyant force___________?

None of these

Depends on the weight of the floating body

Depends on the depth of the submergence of the floating body

For non-symmetrical bodies is not vertical

46 / 50

Cd is always _______ Cc?

Greater than

Equal to

Less than

Either more or less than

47 / 50

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

Either above or below; depends on the liquid density

Below

Above

48 / 50

Differential manometer measures the______?

None of these

Atmospheric pressure

Pressure difference between two points

Sub-atmospheric pressure

49 / 50

Diaphragm valves are used for handling ________ fluids?

Viscous

Corrosive

Non-Newtonian

Solid suspended

50 / 50

Centrifugal pump can?t be used to pump _______?

Thick molten soap at 80?C

None of the above

Moderately viscous vegetable oil used in soap industry

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

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