Discussion
Home ‣ Mechanical Engineering ‣ Heat Transfer, Refrigeration and Air Conditioning Comments
- Question
A heat exchanger with heat transfer surface area A and overall heat transfer coefficient U handles two fluids of heat capacities Cmax and Cmin. The number of transfer units (NTU) used in the analysis of heat exchanger is specified as
Options- A.
- B.
- C. AU Cmin
- D.
- Correct Answer
-
- 1. The centrifugal compressors are generally used for refrigerants that require
Options- A. small displacements and low condensing pressures
- B. large displacements and high condensing pressures
- C. small displacements and high condensing pressures
- D. large displacements and low condensing pressures Discuss
- 2. The multi-stage compression ofair as compared to single stage compression
Options- A. improves volumetric efficiency for the given pressure ratio
- B. reduces workdone per kg of air
- C. gives more uniform torque
- D. all of these Discuss
- 3. Which one of the following is the effect of blade shape on performance of a centrifugal compressor?
Options- A. Backward curved blades has poor efficiency
- B. Backward curved blades lead to stable performance
- C. Forward curved blades has higher efficiency
- D. Forward curved blades produce lower pressure ratio Discuss
- 4. In a two stage reciprocating compressor with intercooler, the amount of work saved with incomplete intercooling is __________ that in case of complete intercooling.
Options- A. less than
- B. more than Discuss
- 5. The efficiency of the vane blower is (where W1 = Workdone due to compression, and W2 = Workdone due to back flow)
Options- A.
- B.
- C.
- D.
Discuss
- 6. Which of the following statement is correct for ammonia as a refrigerant?
Options- A. It is toxic to mucous membranes.
- B. it requires large displacement per TR compared to fluoro carbons.
- C. It reacts with copper and its alloys.
- D. all of these Discuss
- 7. During humidification process, __________ increases.
Options- A. wet bulb temperature
- B. relative humidity
- C. dry bulb temperature
- D. specific humidity Discuss
- 8. Conduction is a process of heat transfer
Options- A. from one particle of the body to another without the actual motion of the particles
- B. from one particle of the body to another by the actual motion of the heated particles.
- C. from a hot body to a cold body, in a straight line, without affecting the intervening medium
- D. none of the above Discuss
- 9. Sulphur dioxide is extremely toxic and non-flammable.
Options- A. True
- B. False Discuss
- 10. A heat pump working on a reversed Carnot cycle has a C.O.P. of 5. It works as a refrigerator taking 1 kW of work input. The refrigerating effect will be
Options- A. 1 kW
- B. 2 kW
- C. 3 kW
- D. 4 kW Discuss
Heat Transfer, Refrigeration and Air Conditioning problems
Search Results
Correct Answer: large displacements and low condensing pressures
Correct Answer: all of these
Correct Answer: Forward curved blades produce lower pressure ratio
Correct Answer: less than
Correct Answer:
Correct Answer: all of these
Correct Answer: relative humidity
Correct Answer: from one particle of the body to another without the actual motion of the particles
Correct Answer: True
Correct Answer: 4 kW
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