Fluid Mechanics for Chemical Quiz 3

1 / 50

Differential manometer measures the______?

None of these

Sub-atmospheric pressure

Pressure difference between two points

Atmospheric pressure

2 / 50

Boundary layer separation occurs when the______?

Valve is closed in a pipeline

Pressure reaches a minimum

Velocity of sound is reached

Cross-section of the channel is reduced

3 / 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

4 / 50

Cocks are used to control _____?

None of these

Water

Solids

Any liquid

5 / 50

Buoyant force___________?

None of these

Depends on the weight of the floating body

For non-symmetrical bodies is not vertical

Depends on the depth of the submergence of the floating body

6 / 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

7 / 50

Capacity of a rotary gear pump can be varied by___________?

All A., B. and C.

Changing the speed of rotation

Bypassing liquid from the suction or discharge line

Bleeding air into suction

8 / 50

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

< 500

< 0.1

< 2100

> 2.5

9 / 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

10 / 50

Check valves are used________?

For unidirectional flow

For controlling water flow

At high pressure

In bends

11 / 50

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

Equal to

More than

Not related to

Less than

12 / 50

Critical velocity in a pipe flow__________?

Increases as pipe diameter increases

Independent of fluid density

Increases as fluid viscosity increases

None of these

13 / 50

Centrifugal pump is normally classified on the basis of the_________?

Type of casing

rpm

Impeller blade angle

Number of blades in impeller

14 / 50

Centrifugal pump can?t be used to pump _______?

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

None of the above

Thick molten soap at 80?C

Moderately viscous vegetable oil used in soap industry

15 / 50

Diaphragm valves are used for handling ________ fluids?

Viscous

Corrosive

Solid suspended

Non-Newtonian

16 / 50

Cp/Cv is termed as___________?

Weber number

Adiabatic constant

Mach number

Prandtl number

17 / 50

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

Keep the pipe in proper orientation

Account for the pressure variation side the pipeline

Make the pipe joint leak-proof

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

18 / 50

Check in a centrifugal pump is_________?

Generally a globe valve

All A., B. and C.

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

19 / 50

Diaphragm pumps are used to transport__________?

Slurries

Solids

Liquids

Fluids

20 / 50

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

Outlet pressure high

Inlet pressure high

Outlet pressure low

Inlet pressure low

21 / 50

Dimension of absolute viscosity is__________?

MLT-1

ML-1T-1

ML-1T

MLT

22 / 50

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

Flow rate through accumulator

Volume available in the cylinder

Amount of energy stored

Rate of falling of ram

23 / 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/?

24 / 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

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

Develops noise

Decrease in effect

Develops high pressure

26 / 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

27 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Have lower operating costs

Have quieter operation

All A., B. and C.

Require less space

28 / 50

Dean number is concerned with the______?

Fluid flow through helical pipes

Power consumption in agitated vessels

Psychrometry

Fluid-particle interaction

29 / 50

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

Loss of kinetic head

Back flow through impeller

Loss of static head

None of these

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) ?

FLT, ML-1T-1

FL-2T, ML-1T-1

ML-1T-3, F-1L2T

F-1L2T-1, MLT-3

31 / 50

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

Occurs when NRe is very small

Is primarily a friction drag

Depends mainly on cross-sectional shape

Is independent of body length

32 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Run at a lower speed for the same discharge

Do not need priming

Deliver fluid with pulsating/fluctuating discharge

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

33 / 50

Check valve is used for _________ flow?

Multidirectional

Very precise control of

Unidirectional

None of these

34 / 50

Centre of pressure of a plane surface of arbitrary shape immersed vertically in a static mass of fluid_________?

Lies above the centroid of the plane surface

Is at the centroid of the plane surface

Is independent of the specific weight of the fluid

Is different for different fluids

35 / 50

Cd is always _______ Cc?

Either more or less than

Equal to

Less than

Greater than

36 / 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

37 / 50

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

F-1. L

FL-1

F.L-2

F-2. L

38 / 50

Cavitation can be prevented by_________?

Maintaining the suction head sufficiently greater than the vapour pressure

Maintaining suction head lower than the vapour pressure

Maintaining suction head = developed head

Suitably designing the pump

39 / 50

Choking in case of pipe flow means that a_____?

Valve is closed in the line

None of these

Restriction in flow cross-section area occurs

Specified mass flow rate cannot be achieved

40 / 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

Equal to the vapour pressure

Greater than the vapour pressure of the liquid at that temperature

41 / 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___________?

0.42

0.82

0.98

0.62

42 / 50

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

Hagen-Poiseuille?s equation

Navier-stokes equation

None of these

Stoke?s law

43 / 50

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

Flow of liquid during operation of the pump

All A., B. and C.

Discharge pressure

Back flow of fluid in the event of stoppage of pump

44 / 50

Cd for the orifice plate varies from _____?

0.93 to 0.98

0.58 to 0.8

0.2 to 0.3

0.02 to 0.03

45 / 50

Curve III in the bellow diagram represents a/an_________?

None of these

Pseudo plastic fluid

Dilatent fluid

Ideal plastic

46 / 50

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

d1/3

d2/3

47 / 50

Differential manometer measures the_____?

Pressure difference

Pressure gradient

Absolute pressure

Gauge pressure

48 / 50

Dimension of kinematic viscosity is_______?

L2T-2

L2T

L2T-1

MLT-1

49 / 50

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

Either above or below; depends on the liquid density

Above

Below

50 / 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, 5.3 inches of Hg

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

10 psi, 19.7 ft. of water, 23.3 inches of Hg

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