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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- A. Mercury
- B. Water
- C. Carbon tetrachloride
- D. None of these
Explanation: Dynamic viscosity and kinematic viscosity are related by μ = ρν. Their numerical values are equal when the density is approximately 1…
Correct answer: Water- A. Condense steam
- B. Release excess steam pressure by bleeding steam
- C. None of these
- D. Remove condensate and inert gases
Explanation: Steam traps automatically discharge condensate and usually remove non-condensable gases while retaining live steam in the line.
Correct answer: Remove condensate and inert gases- A. Different
- B. Same
- C. Never different
- D. Linearly related
Explanation: In an annulus, the pressure-drop wetted perimeter includes every wall in contact with the fluid, whereas the heat-transfer perimeter…
Correct answer: Different- A. Increase very rapidly
- B. Increase slowly
- C. Decrease slowly
- D. Remain unaffected
Explanation: Unlike liquids, gases become more viscous as temperature rises because faster molecular motion increases momentum transfer between layers.
Correct answer: Increase slowly- A. When fluid flows past a smooth surface
- B. At low velocity
- C. At high fluid velocity
- D. None of these
Explanation: Frictional heat generation increases strongly with fluid velocity because the pressure drop and viscous dissipation rise with flow rate.
Correct answer: At high fluid velocity- A. 1.5
- B. 3
- C. 5
- D. 9
Explanation: Screwed pipe fittings are convenient for small-diameter piping but become impractical for larger sizes because of threading, leakage, and…
Correct answer: 3- A. 300
- B. 600
- C. 1000
- D. 1500
Explanation: At about 200 poise, angled baffles reduce vortex formation without excessively disturbing the viscous liquid.
Correct answer: 600- A. 60
- B. Negligible
- C. 350
- D. 200
Explanation: Couplings and unions provide a nearly straight-through passage, so their additional resistance is normally treated as negligible in…
Correct answer: Negligible- A. 250 and 600
- B. 3 and 5
- C. 100 and 250
- D. 25 and 60
Explanation: The equivalent-length ratios are approximately 25 for a medium-radius 90° elbow and 60 for a square elbow.
Correct answer: 25 and 60- A. From rolled strips formed into cylinders and seam-welded
- B. By extrusion & casting into static and centrifugal molds
- C. Both B. and C.
- D. point and further reducing it by rolling gas drawing
- E. By forging a solid round, piercing it by simultaneously rotating & forcing it over a piercer
Explanation: Seamless pipe can be produced by extrusion or centrifugal casting, and also by piercing a rotating solid billet followed by rolling or…
Correct answer: Both B. and C.- A. d2/(d1 + d2)
- B. d1/(d1 + d2)
- C. (d1 + d2)/d1
- D. (d1 + d2)/d2
Explanation: For an annulus, the pressure-drop diameter is the hydraulic diameter, d2 − d1, while the heat-transfer diameter based on the inner surface…
Correct answer: d1/(d1 + d2)- A. Viscosity of the fluid
- B. Density of the fluid
- C. Total cost considerations (pumping cost plus fixed cost of the pipe)
- D. None of these
Explanation: The economic diameter balances the annual pumping cost against the fixed cost of installing the pipe.
Correct answer: Total cost considerations (pumping cost plus fixed cost of the pipe)- A. Less than that for Tee (used as elbow, entering run)
- B. More than that for Tee (used as elbow, entering run)
- C. Around 90
- D. Both B. and C.
Explanation: Flow entering the branch of a tee makes a sharp turn and has a greater equivalent length than flow entering the run.
Correct answer: Both B. and C.- A. Decreases
- B. Increases
- C. Remain unaffected
- D. May increase or decrease depending upon whether the fluid is Newtonian or non-Newtonian
Explanation: Increasing pipe diameter reduces frictional resistance and therefore the pumping head and power required for a given flow rate.
Correct answer: Decreases- A. 0.1
- B. 0.8
- C. 0.25
- D. 0.5
Explanation: For a paddle agitator, the paddle diameter is commonly selected at about 0.8 times the tank diameter.
Correct answer: 0.8- A. ≤ 1
- B. > 2.5
- C. ≤ 2
- D. > 3.5
Explanation: Brass valves are generally used for small pipe sizes, commonly up to about 2 inches, because brass is economical and suitable for…
Correct answer: ≤ 2- A. 0.1-0.5
- B. 15-30
- C. 10-50
- D. 1-2
Explanation: Water is commonly conveyed in pipes at about 1–2 m/s, which provides practical flow without excessive friction loss, erosion, or water…
Correct answer: 1-2- A. 0.1 to 0.25
- B. 0.3 to 0.5
- C. 0.5 to 0.6
- D. 0.65 to 0.80
Explanation: For high-viscosity mixing, a multiple-blade paddle is broad enough to move paste effectively, with blade width commonly about 10 to 25% of…
Correct answer: 0.1 to 0.25- A. Called tube pitch
- B. Called tube clearance
- C. More in case of triangular pitch as compared to square pitch of tube layout
- D. None of these
Explanation: Tube clearance is the shortest gap between the outside surfaces of adjacent tubes, whereas tube pitch is measured from the centre of one…
Correct answer: Called tube clearance- A. Increases
- B. Remain unaffected
- C. Decreases
- D. None of these
Explanation: A higher gas-to-cloth ratio means more gas passes through each unit area of filter cloth, so less cloth area and a smaller, cheaper filter…
Correct answer: Decreases