Fluid Mechanics for Chemical Quiz 3

1 / 50

Dean number is concerned with the______?

Fluid-particle interaction

Fluid flow through helical pipes

Psychrometry

Power consumption in agitated vessels

2 / 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.

3 / 50

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

Account for the pressure variation side the pipeline

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

Make the pipe joint leak-proof

Keep the pipe in proper orientation

4 / 50

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

More than

Less than

Equal to

Not related to

5 / 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

6 / 50

Cavitation can be prevented by_________?

Suitably designing the pump

Maintaining suction head lower than the vapour pressure

Maintaining suction head = developed head

Maintaining the suction head sufficiently greater than the vapour pressure

7 / 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

8 / 50

Curve III in the bellow diagram represents a/an_________?

None of these

Ideal plastic

Pseudo plastic fluid

Dilatent fluid

9 / 50

Buoyant force___________?

None of these

Depends on the depth of the submergence of the floating body

For non-symmetrical bodies is not vertical

Depends on the weight of the floating body

10 / 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

11 / 50

Capacity of a rotary gear pump can be varied by___________?

Changing the speed of rotation

All A., B. and C.

Bypassing liquid from the suction or discharge line

Bleeding air into suction

12 / 50

Cd is always _______ Cc?

Equal to

Less than

Either more or less than

Greater than

13 / 50

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

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 developed head

Equal to the vapour pressure

14 / 50

Differential manometer measures the_____?

Absolute pressure

Pressure difference

Pressure gradient

Gauge pressure

15 / 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, 23.3 inches of Hg

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

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

16 / 50

Boundary layer separation occurs when the______?

Pressure reaches a minimum

Velocity of sound is reached

Cross-section of the channel is reduced

Valve is closed in a pipeline

17 / 50

Check valves are used________?

In bends

At high pressure

For controlling water flow

For unidirectional flow

18 / 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?

All A., B. and C.

Head of the liquid pumped

BHP required by the pump

NPSH required

19 / 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

20 / 50

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

Inlet pressure low

Inlet pressure high

Outlet pressure high

Outlet pressure low

21 / 50

Differential manometer measures the______?

None of these

Atmospheric pressure

Sub-atmospheric pressure

Pressure difference between two points

22 / 50

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

Loss of kinetic head

Back flow through impeller

None of these

Loss of static head

23 / 50

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

d2/3

d1/3

24 / 50

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

< 2100

< 500

< 0.1

> 2.5

25 / 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

0.62

0.98

26 / 50

Critical velocity in a pipe flow__________?

Increases as fluid viscosity increases

Independent of fluid density

None of these

Increases as pipe diameter increases

27 / 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.

Discharge pressure

Flow of liquid during operation of the pump

28 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Do not need priming

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

29 / 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

30 / 50

Dimension of absolute viscosity is__________?

ML-1T-1

MLT

MLT-1

ML-1T

31 / 50

Check valve is used for _________ flow?

Unidirectional

Very precise control of

None of these

Multidirectional

32 / 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/?

33 / 50

Cocks are used to control _____?

None of these

Any liquid

Solids

Water

34 / 50

Centrifugal pump is normally classified on the basis of the_________?

rpm

Impeller blade angle

Type of casing

Number of blades in impeller

35 / 50

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

None of these

Navier-stokes equation

Stoke?s law

Hagen-Poiseuille?s equation

36 / 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

37 / 50

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

Below

Either above or below; depends on the liquid density

Above

38 / 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

39 / 50

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

Volume available in the cylinder

Flow rate through accumulator

Amount of energy stored

Rate of falling of ram

40 / 50

Cp/Cv is termed as___________?

Prandtl number

Mach number

Adiabatic constant

Weber number

41 / 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

42 / 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

Lies above the centroid of the plane surface

Is different for different fluids

Is independent of the specific weight of the fluid

43 / 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)

44 / 50

Diaphragm valves are used for handling ________ fluids?

Non-Newtonian

Viscous

Corrosive

Solid suspended

45 / 50

Diaphragm pumps are used to transport__________?

Slurries

Solids

Fluids

Liquids

46 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Require less space

Have quieter operation

All A., B. and C.

Have lower operating costs

47 / 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

FL-2T, ML-1T-1

ML-1T-3, F-1L2T

F-1L2T-1, MLT-3

48 / 50

Dimension of kinematic viscosity is_______?

L2T-1

L2T

L2T-2

MLT-1

49 / 50

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

F-1. L

FL-1

F-2. L

F.L-2

50 / 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

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