Free Fluid Flow Operations MCQs with Answers
909 Fluid Flow Operations MCQs from Chemical Engineering, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
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909 questions · page 30 of 46
- A. Kozeny-Carman
- B. Hagen-Poiseuille's
- C. Leva's
- D. Blake-Plummer
Explanation: The Blake-Plummer equation describes pressure loss through a packed bed when inertial or turbulent effects dominate.
Correct answer: Blake-Plummer- A. Decreases the work done
- B. Increases the work done
- C. Causes cavitation
- D. Results in non-uniform discharge
Explanation: An air vessel stores liquid during part of the reciprocating cycle and returns it during another part, reducing acceleration effects and…
Correct answer: Decreases the work done- A. 0.25
- B. 0.5
- C. 0.66
- D. 0.95
Explanation: For maximum discharge in a circular open channel, the hydraulic radius is optimized at a depth of about 0.94 times the diameter.
Correct answer: 0.95- A. 98
- B. 147
- C. 196
- D. 49
Explanation: The pressure head relation is P = ρgh. For 10 m of water, P = 1000 × 9.81 × 10 Pa ≈ 98.1 kN/m², giving 98 kN/m².
Correct answer: 98- A. Neither A. nor B.
- B. Compressible
- C. Both A. and B.
- D. Non-isothermal condition of
Explanation: The usual Fanning friction-factor equation is formulated for steady, fully developed pipe flow with constant fluid properties.
Correct answer: Neither A. nor B.- A. 10 m
- B. 11 m
- C. 11.8 m
- D. 30 m
Explanation: The static elevation head is 10 m, while friction loss is approximately 4f(L/D)(v²/2g) = 0.99 m, using v = Q/A ≈ 0.51 m/s.
Correct answer: 11 m- A. Atmospheric air
- B. Water
- C. Compressed air
- D. None of these
Explanation: An air vessel contains a trapped air cushion that is compressed during operation and smooths the fluctuating discharge of a reciprocating…
Correct answer: Compressed air- A. Fanning's
- B. Hagen-Poiseuille's
- C. Ergun's
- D. None of these
Explanation: The Ergun equation combines viscous and inertial pressure-drop effects for flow through packed beds.
Correct answer: Ergun's- A. 2y/3
- B. 1/(y/3)
- C. 1/(y/4)
- D. 3y/4
Explanation: For a vertical rectangular surface extending from the free surface to depth y, the centre of pressure lies at 2y/3 because pressure…
Correct answer: 2y/3- A. The pressure drop is less than that for batch fluidisation
- B. Solids are completely entrained
- C. There is no entrainment of solids
- D. Velocity of the fluid is very small
Explanation: Continuous fluidisation operates at a velocity high enough for particles to be carried out with the fluid stream, so solids are…
Correct answer: Solids are completely entrained- A. Shear stress
- B. Shear force
- C. Average drag per unit projected area
- D. None of these
Explanation: The drag coefficient is Cd = drag force divided by dynamic pressure times projected area.
Correct answer: Average drag per unit projected area- A. Increases
- B. May increase or decrease
- C. Remain same
- D. Decreases
Explanation: For a flat plate, laminar boundary-layer thickness varies approximately as δ ∝ x/√Reₓ.
Correct answer: Decreases- A. 5
- B. 50
- C. 500
- D. 5000
Explanation: The turbulent entrance length is commonly taken as about 10 to 60 pipe diameters, with 50 diameters used as a standard estimate.
Correct answer: 50- A. Run at a lower speed for the same discharge
- B. Can be run with discharge line valve closed for a short interval
- C. Deliver fluid with pulsating/fluctuating discharge
- D. Do not need priming
Explanation: A centrifugal pump can tolerate a briefly closed discharge valve, although prolonged operation causes overheating because the liquid…
Correct answer: Can be run with discharge line valve closed for a short interval- A. 5
- B. 10
- C. 50
- D. 100
Explanation: The theoretical suction lift is limited by atmospheric pressure, which supports about 10.3 m of water at sea level before vapour-pressure…
Correct answer: 10- A. Globe valve
- B. Gate valve
- C. Butterfly valve
- D. Check valve
Explanation: A globe valve has a flow path designed for throttling, so its opening can be adjusted accurately to control flow.
Correct answer: Globe valve- A. Facilitate unidirectional flow of liquid
- B. Protect the pump against developing excessive pressure
- C. Reduce the discharge pressure
- D. Control the rate of discharge
Explanation: A reciprocating pump is a positive-displacement pump, so a blocked discharge can make pressure rise rapidly.
Correct answer: Protect the pump against developing excessive pressure- A. 2 to 10
- B. 0.1 to 2
- C. 0.01 to 0.1
- D. 10 to 100
Explanation: Stokes' law applies in the creeping-flow regime, where particle Reynolds number is very small, conventionally below about 0.1 for high…
Correct answer: 0.01 to 0.1- A. 200 meters
- B. Infinitely long
- C. More than 105.7 metres
- D. Equal to the height of the hot gas column producing draught
Explanation: Increasing chimney height increases draught only up to the optimum condition; maximum discharge occurs when the chimney height equals the…
Correct answer: Equal to the height of the hot gas column producing draught- A. Both A. & B.
- B. Its height
- C. Temperature of the flue gas
- D. Neither A. nor B.
Explanation: Chimney draft increases with chimney height and with the temperature difference between hot flue gas and outside air.
Correct answer: Both A. & B.