Fluid Mechanics for Chemical Quiz 3

1 / 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)

2 / 50

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

d1/3

d2/3

3 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Deliver fluid with pulsating/fluctuating discharge

Do not need priming

Run at a lower speed for the same discharge

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

4 / 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

5 / 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

6 / 50

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

Inlet pressure low

Outlet pressure high

Inlet pressure high

Outlet pressure low

7 / 50

Boundary layer separation occurs when the______?

Cross-section of the channel is reduced

Valve is closed in a pipeline

Pressure reaches a minimum

Velocity of sound is reached

8 / 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

9 / 50

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

Is independent of body length

Occurs when NRe is very small

Is primarily a friction drag

Depends mainly on cross-sectional shape

10 / 50

Dimension of absolute viscosity is__________?

ML-1T-1

MLT

ML-1T

MLT-1

11 / 50

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

Discharge pressure

Back flow of fluid in the event of stoppage of pump

Flow of liquid during operation of the pump

All A., B. and C.

12 / 50

Cp/Cv is termed as___________?

Weber number

Mach number

Prandtl number

Adiabatic constant

13 / 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/?

14 / 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

Is different for different fluids

Lies above the centroid of the plane surface

15 / 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

Head of the liquid pumped

All A., B. and C.

16 / 50

Diaphragm valves are used for handling ________ fluids?

Viscous

Corrosive

Solid suspended

Non-Newtonian

17 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Require less space

Have lower operating costs

All A., B. and C.

Have quieter operation

18 / 50

Capacity of a rotary gear pump can be varied by___________?

Bypassing liquid from the suction or discharge line

All A., B. and C.

Changing the speed of rotation

Bleeding air into suction

19 / 50

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

Below

Above

Either above or below; depends on the liquid density

20 / 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

21 / 50

Curve III in the bellow diagram represents a/an_________?

None of these

Pseudo plastic fluid

Dilatent fluid

Ideal plastic

22 / 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

23 / 50

Diaphragm pumps are used to transport__________?

Fluids

Liquids

Slurries

Solids

24 / 50

Differential manometer measures the______?

None of these

Atmospheric pressure

Pressure difference between two points

Sub-atmospheric pressure

25 / 50

Cavitation in a pump creates so many undesirable effects. Out of the following, which is not an undesirable effect created by cavitation ?

Increase in thrust

Decrease in effect

Develops high pressure

Develops noise

26 / 50

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

Equal to

More than

Less than

Not related to

27 / 50

Cocks are used to control _____?

Solids

Any liquid

Water

None of these

28 / 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

29 / 50

Choking in case of pipe flow means that a_____?

Restriction in flow cross-section area occurs

Valve is closed in the line

None of these

Specified mass flow rate cannot be achieved

30 / 50

Dimension of kinematic viscosity is_______?

L2T

MLT-1

L2T-2

L2T-1

31 / 50

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

Stoke?s law

Navier-stokes equation

Hagen-Poiseuille?s equation

None of these

32 / 50

Check valves are used________?

At high pressure

For unidirectional flow

For controlling water flow

In bends

33 / 50

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

< 500

< 0.1

> 2.5

< 2100

34 / 50

Dean number is concerned with the______?

Fluid flow through helical pipes

Power consumption in agitated vessels

Fluid-particle interaction

Psychrometry

35 / 50

Cd is always _______ Cc?

Equal to

Either more or less than

Greater than

Less than

36 / 50

Differential manometer measures the_____?

Gauge pressure

Pressure gradient

Pressure difference

Absolute pressure

37 / 50

Cavitation can be prevented by_________?

Maintaining suction head = developed head

Suitably designing the pump

Maintaining the suction head sufficiently greater than the vapour pressure

Maintaining suction head lower than the vapour pressure

38 / 50

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

Loss of static head

Loss of kinetic head

None of these

Back flow through impeller

39 / 50

Centrifugal pump is normally classified on the basis of the_________?

Number of blades in impeller

Type of casing

Impeller blade angle

rpm

40 / 50

Check in a centrifugal pump is_________?

Provided in the discharge line

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

Generally a globe valve

All A., B. and C.

41 / 50

Cd for the orifice plate varies from _____?

0.58 to 0.8

0.2 to 0.3

0.93 to 0.98

0.02 to 0.03

42 / 50

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

Flow rate through accumulator

Amount of energy stored

Rate of falling of ram

Volume available in the cylinder

43 / 50

Critical velocity in a pipe flow__________?

Independent of fluid density

None of these

Increases as fluid viscosity increases

Increases as pipe diameter increases

44 / 50

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

F.L-2

F-2. L

FL-1

F-1. L

45 / 50

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

Less than the vapour pressure of the liquid at that temperature

Equal to the vapour pressure

Greater than the vapour pressure of the liquid at that temperature

Equal to the developed head

46 / 50

Check valve is used for _________ flow?

Very precise control of

None of these

Multidirectional

Unidirectional

47 / 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

0.98

0.62

0.42

48 / 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

Data not sufficient to relate f1 & f2

f1 = f2

f1 > f2

49 / 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

0.01 to 0.10

200 to 300

50 / 50

Buoyant force___________?

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

None of these

Provide Your Information

NameEmailPhone Number

Your score is

The average score is 0%