Fluid Mechanics for Chemical Quiz 3

1 / 50

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

Outlet pressure high

Inlet pressure high

Outlet pressure low

Inlet pressure low

2 / 50

Check valve is used for _________ flow?

None of these

Unidirectional

Multidirectional

Very precise control of

3 / 50

Cp/Cv is termed as___________?

Mach number

Adiabatic constant

Weber number

Prandtl number

4 / 50

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

Not related to

Equal to

More than

Less than

5 / 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

6 / 50

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

Account for the pressure variation side the pipeline

Make the pipe joint leak-proof

Keep the pipe in proper orientation

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

7 / 50

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

Depends mainly on cross-sectional shape

Occurs when NRe is very small

Is primarily a friction drag

Is independent of body length

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

Choose the set of pressure intensities that are equivalent ?

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

4.33 psi, 10 ft. of water, 8.83 inches of Hg

10 / 50

Cd is always _______ Cc?

Equal to

Either more or less than

Greater than

Less than

11 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Require less space

All A., B. and C.

Have quieter operation

Have lower operating costs

12 / 50

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

Equal to the vapour pressure

Greater than the vapour pressure of the liquid at that temperature

Equal to the developed head

Less than the vapour pressure of the liquid at that temperature

13 / 50

Buoyant force___________?

Depends on the depth of the submergence of the floating body

Depends on the weight of the floating body

For non-symmetrical bodies is not vertical

None of these

14 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Do not need priming

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

15 / 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

16 / 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

17 / 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

18 / 50

Cd for the orifice plate varies from _____?

0.02 to 0.03

0.58 to 0.8

0.93 to 0.98

0.2 to 0.3

19 / 50

Diaphragm pumps are used to transport__________?

Fluids

Liquids

Solids

Slurries

20 / 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) ?

ML-1T-3, F-1L2T

FLT, ML-1T-1

FL-2T, ML-1T-1

F-1L2T-1, MLT-3

21 / 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

Lies above the centroid of the plane surface

Is different for different fluids

Is at the centroid of the plane surface

22 / 50

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

F-1. L

FL-1

F-2. L

F.L-2

23 / 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.

24 / 50

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

< 2100

< 0.1

< 500

> 2.5

25 / 50

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

d2/3

d1/3

26 / 50

Capacity of a rotary gear pump can be varied by___________?

Bypassing liquid from the suction or discharge line

Bleeding air into suction

Changing the speed of rotation

All A., B. and C.

27 / 50

Boundary layer separation occurs when the______?

Pressure reaches a minimum

Valve is closed in a pipeline

Cross-section of the channel is reduced

Velocity of sound is reached

28 / 50

Dean number is concerned with the______?

Fluid flow through helical pipes

Psychrometry

Power consumption in agitated vessels

Fluid-particle interaction

29 / 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?

Head of the liquid pumped

BHP required by the pump

All A., B. and C.

NPSH required

30 / 50

Cocks are used to control _____?

None of these

Water

Any liquid

Solids

31 / 50

Centrifugal pump can?t be used to pump _______?

Moderately viscous vegetable oil used in soap industry

None of the above

Thick molten soap at 80?C

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

32 / 50

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

Above

Either above or below; depends on the liquid density

Below

33 / 50

Differential manometer measures the_____?

Gauge pressure

Pressure difference

Pressure gradient

Absolute pressure

34 / 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

35 / 50

Check in a centrifugal pump is_________?

All A., B. and C.

Generally a globe valve

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

36 / 50

Check valves are used________?

For controlling water flow

In bends

At high pressure

For unidirectional flow

37 / 50

Curve III in the bellow diagram represents a/an_________?

Ideal plastic

None of these

Pseudo plastic fluid

Dilatent fluid

38 / 50

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

None of these

Stoke?s law

Navier-stokes equation

Hagen-Poiseuille?s equation

39 / 50

Centrifugal pump is normally classified on the basis of the_________?

Impeller blade angle

Number of blades in impeller

rpm

Type of casing

40 / 50

Cavitation can be prevented by_________?

Maintaining suction head = developed head

Maintaining suction head lower than the vapour pressure

Maintaining the suction head sufficiently greater than the vapour pressure

Suitably designing the pump

41 / 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

42 / 50

Dimension of kinematic viscosity is_______?

L2T-2

L2T-1

L2T

MLT-1

43 / 50

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

Flow rate through accumulator

Rate of falling of ram

Amount of energy stored

Volume available in the cylinder

44 / 50

Dimension of absolute viscosity is__________?

MLT

ML-1T

ML-1T-1

MLT-1

45 / 50

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

Back flow through impeller

None of these

Loss of kinetic head

Loss of static head

46 / 50

Diaphragm valves are used for handling ________ fluids?

Corrosive

Solid suspended

Viscous

Non-Newtonian

47 / 50

Differential manometer measures the______?

Pressure difference between two points

None of these

Sub-atmospheric pressure

Atmospheric pressure

48 / 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

49 / 50

Brownian movement is prominent in the particle size range of ______ microns in case of settling of a particle in a fluid?

2 to 3

200 to 300

100 to 1000

0.01 to 0.10

50 / 50

Critical velocity in a pipe flow__________?

None of these

Increases as fluid viscosity increases

Independent of fluid density

Increases as pipe diameter increases

Provide Your Information

NameEmailPhone Number

Your score is

The average score is 0%