chemical engineering fluid mechanics for chemical chemical engineering mcqs to prepare for nts, kppsc, fpsc, ppsc and more

chemical engineering fluid mechanics for chemical chemical engineering Mcqs

351. Quicksand is an example of a __________ fluid?
0

A. Pseudo plastic

B. Dilatant

C. Newtonian

D. Bingham plastic

352. Bernoullis equation for steady, frictionless, continuous flow states that the ______________ at all sections is same?
0

A. Total energy

B. Velocity head

C. Total pressure

D. None of these

353. Umf is the minimum fluidisation velocity for a bed of particles. An increase in the superficial gas velocity from 2 Umf to 2.5 Umf results in (all velocities are smaller than the entrainment velocity of the particles) no change in the_______________?
0

A. Drag on column walls

B. Drag on particles

C. Bed height

D. Bed voidage

354. A 0.5 m high bed made up of a 1 mm dia glass sphere (density 2500 kg/m3 ) is to be fluidised by water (density 1000 kg/m3 ). If at the point of incipient fluidisation, the bed voidage is 40%, the pressure drop across the bed is________________?
0

A. None of these

B. 4.4 KPa

C. 3.7 KPa

D. 2.94 KPa

355. Which of the following exemplifies a three dimensional fluid flow ?
0

A. None of these

B. Fluid flow between parallel plates

C. Fluid flow at the inlet to a nozzle

D. Viscous fluid flow between converging plates

356. The Reynolds number for an ideal fluid flow is _________________?
0

A. ?

B. 4000

C. 4

D. 2100-4000

357. Shear stress in a fluid flowing in a round pipe_________________?
0

A. Is zero at the wall and increases linearly to the centre

B. Is zero at the centre and varies linearly with the radius

C. Varies parabolically across the cross-section

D. Remains constant over the cross-section

358. The actual velocity at vena-contracta for flow through an orifice from a reservoir is given by_____________________?
0

A. Cv . Va

B. Cv . ?(2gH)

C. Cd . ?(2gH)

D. Cc . ?(2gH)

359. The pressure head on sudden contraction in a horizontal pipe is converted into the _____________ head?
0

A. Elevation

B. Velocity

C. Both A. & B.

D. Neither A. nor B.

360. In centrifugal pump operation, the cavitation can be eliminated by maintaining suction pressure ______________ the vapor pressure of the liquid at the suction temperature?
0

A. Equal to

B. Lower than

C. Higher than

D. None of these

361. Terminal velocity is_____________________?
0

A. None of these

B. A constant velocity with no acceleration

C. A fluctuating velocity

D. Attained after moving one-half of total distance

362. Permanent loss in a Venturimeter is about ___________ percent of the pressure drop in the upstream cone?
0

A. 70

B. 1

C. 40

D. 10

363. If three pipes of different diameters, lengths & friction factors are connected in parallel, then (where, Q = flow rate, V= fluid velocity f = friction factor). ?
0

A. V1 = V2 = V3

B. f = f1 + f2 + f3

C. Q = Q1 + Q2 + Q3

D. Q1 = Q2 = Q3

364. Propellers are____________________?
0

A. Used for mixing liquids of high viscosity

B. Radial flow mixers

C. Low speed impeller

D. Axial flow mixers

365. For laminar flow of a shear thinning liquid in a pipe, if the volumetric flow rate is doubled, the pressure gradient will increase by a factor of_________________?
0

A. 2

B. 2-Jan

C. 2

366. Which of the following properties of a fluid is responsible for offering resistance to shear ?
0

A. Specific gravity

B. All A., B., and C.

C. Surface tension

D. Viscosity

367. Which of the following is not a dimension-less parameter ?
0

A. None of these

B. Specific gravity

C. Euler number

D. Fanning friction factor

368. _____________________ pumps are a group of vacuum pumps ?
0

A. Submerged

B. Sump

C. Mono

D. Hyster

369. ____________ flow means the flow of incompressible fluid with no shear ?
0

A. Potential

B. Creep

C. Boundary layer

D. Streamline

370. Potential flow is the flow of______________?
0

A. Compressible fluids with shear

B. Incompressible fluids with no shear

C. Incompressible fluids with shear

D. Compressible fluids with no shear

371. Sewage sludge is ______________ type of non-Newtonian fluid?
0

A. Bingham plastic

B. Pseudo plastic

C. None of these

D. Dilatant

372. Maximum theoretical suction lift for water at 15C by a centrifugal pump is 34 ft. The same for water at 90C will be _____________________ ft?
0

A. 8

B. 40

C. 34

D. 37

373. _____________ forces do not act in case of fluid flow ?
0

A. Elastic

B. Centrifugal

C. Tensile

D. Vibratory

374. The pressure and power requirement of a gas fan at constant speed & capacity varies ____________ the gas density?
0

A. Inversely as square root of

B. Directly as

C. Inversely as

D. As square of

375. The most serious disadvantage of an orificemeter is that________________?
0

A. It is not very accurate

B. It is not suitable for measuring gas flow

C. Most of the pressure drop is not recoverable

D. It is very costly

376. Medium viscosity lubricating oil can be most ideally pumped by a ______________ pump?
0

A. Piston

B. Centrifugal

C. Vane

D. Plunger

377. Propeller type centrifugal pumps are most suitable for__________________?
0

A. High capacity at high heads

B. Low capacity at low heads

C. High capacity at low heads

D. Low capacity at high heads

378. Boundary layer separation is caused by the ____________________?
0

A. Reduction of pressure gradient to zero

B. Reduction of boundary layer thickness to zero

C. Adverse pressure gradient

D. Reduction of pressure below vapour pressure

379. The variable required to be known in correlations used for estimating the horse power of a centrifugal gas compressor and hence its cost is P. Inlet pressure Q. Compressor rpm R. Delivery pressure S. Volumetric flow rate at inlet ?
0

A. P, Rand S

B. R and S

C. P, Q and R

D. P and R

380. The co-efficient of discharge of an orificemeter is a function of ________________?
0

A. Reynolds number at the orifice

B. Ratio of orifice dia to pipe dia

C. Both A. and B.

D. None of the above parameters, and has a constant value of 0.61

381. Which of the following equations applies to the fluid flow through a packed bed for very large Reynolds number ?
0

A. Fanning equation

B. Kozeny-Carman equation

C. Hagen-Poiseuille equation

D. Blake-Plummer equation

382. Power required for mixing Newtonian fluids is a function of the _________________?
0

A. None of these

B. Density of fluid, viscosity of fluid & impeller dia only

C. Density & viscosity of fluid only

D. Speed of impeller, diameter of impeller & viscosity

383. A compressor that takes suction at a pressure below atmospheric and discharge against atmospheric pressure is called a ____________ pump?
0

A. Submerged

B. Volute

C. Sump

D. Vacuum

384. Dimension of surface tension is (where, F = force, L = length) ?
0

A. F-2. L

B. FL-1

C. F-1. L

D. F.L-2

385. Pressure drop in a packed bed for laminar flow is given by the ______________ equation?
0

A. Fanning friction factor

B. Levas

C. Kozeny-Carman

D. Blake-Plummer

386. In area meter (e.g., Rotameter), with increase in the fluid flow rate, the___________________?
0

A. None of these

B. Pressure drop is almost constant

C. Area through which fluid flows does not vary

D. Pressure drop increases linearly

387. Where does the maximum stress occur in case of laminar flow of incompressible fluid in a closed conduit of diameter d ?
0

A. At d/8 from the wall

B. At the centre

C. At the wall

D. At d/4 from the wall

388. Upto what value of Mach number, a fluid may be considered as incompressible ?
0

A. 10

B. 0.03

C. 0.3

D. 3

389. The discharge through a semi-circular weir varies as (where, H = Head of liquid.) ?
0

A. H2

B. H1/2

C. H3/2

D. H

390. Erosion and pits formation on the impeller of a centrifugal pump may be due to________________?
0

A. Low speed of impeller

B. Cavitation

C. Off centering of pump with motor

D. Its operation with delivery valve closed for considerable time after starting the pump

391. Foot valves provided in pumps are ____________ valves?
0

A. Pressure reducing

B. Directional control

C. Relief

D. Three/four way

392. Unsteady uniform flow is represented by flow through a/an_________________?
0

A. Expanding tube at constant rate

B. Expanding tube at increasing rate

C. Long pipe at constant rate

D. Long pipe at decreasing rate

393. When the pipe Reynolds number is 6000, the flow is generally___________________?
0

A. Transition

B. Laminar

C. Viscous

D. Turbulent

394. Isotropic turbulence occurs __________________?
0

A. Only in Newtonian fluids

B. At higher temperatures

C. Where there is no velocity gradient

D. None of these

395. Rotary vacuum pumps can reduce the absolute pressure to as low as __________ mm Hg ?
0

A. 1

B. 0.01

C. 0.001

D. 0.1

396. What is the force required (in Newtons) to hold a spherical balloon stationary in water at a depth of H from the air-water interface? The balloon is of radius 0.1 m and is filled with air ?
0

A. 0.01 ?gH/8

B. 4?g/3

C. 0.01 ?gH/4

D. 0.04 ?gH/3

397. The ____________ is measured by a piezometric opening?
0

A. Dynamic pressure

B. Total pressure

C. Point velocity

D. Static pressure

398. If more than two branches of pipes are to be connected at the same point, then use a/an_________________?
0

A. Union

B. None of these

C. Elbow

D. Tee

399. Hydraulic radius is the ratio of ____________________?
0

A. Square root of flow area to wetted perimeter

B. Flow area to square of wetted perimeter

C. Wetted perimeter to flow area

D. Flow area to wetted perimeter

400. A lubricant 100 times more viscous than water would have a viscosity (in Pa.s) ?
0

A. 0.1

B. 1

C. 0.01

D. 10

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