Mechanical Engineering

Question: Air motors work on the cycle which is the reverse of the reciprocating air compressor cycle.
[A].

Agree

[B].

Disagree

Answer: Option A

Explanation:

No answer description available for this question.

Question: In reciprocating air compressors, isothermal efficiency is used for all sorts of calculations.
[A].

Correct

[B].

Incorrect

Answer: Option A

Explanation:

No answer description available for this question.

Question: With the decrease in compression ratio, the volumetric efficiency
[A].

does not change

[B].

increases

[C].

decreases

Answer: Option B

Explanation:

No answer description available for this question.

Question: If the clearance ratio for a reciprocating air compressor is ‘K’, then its volumetric efficiency is given by
[A].

[B].

[C].

[D].

Answer: Option B

Explanation:

No answer description available for this question.

Question: Which of the following statement is wrong?
[A].

In a two stage reciprocating air compressor with complete intercooling, maximum work is saved.

[B].

The minimum work required for a two stage reciprocating air compressor is double the work required for each stage.

[C].

The ratio of the volume of free air delivery per stroke to the swept volume of the piston is called volumetric efficiency.

[D].

none of the above

Answer: Option D

Explanation:

No answer description available for this question.

Question: For a multi-stage compressor, the polytropic efficiency is constant throughout for all the stages.
[A].

True

[B].

False

Answer: Option A

Explanation:

No answer description available for this question.

Question: For a two stage reciprocating compressor, compression from p1 to p3 is with perfect intercooling and no pressure losses. If compression in both the cylinders follows the same polytropic process and the atmospheric pressure is pa, then the intermediate pressure p2 is given by
[A].

p2 = (p1 + p3)/2

[B].

p2 = p1.p3

[C].

P2 = Pa x p3/p1

[D].

p2 = pa p3/p1

Answer: Option B

Explanation:

No answer description available for this question.

Question: In a four stage compressor, if the pressure at the first and third stage are 1 bar and 16 bar, then the delivery pressure at the fourth stage will be
[A].

1 bar

[B].

16 bar

[C].

64 bar

[D].

256 bar

Answer: Option C

Explanation:

No answer description available for this question.

Question: In n1 and n2 are the indices of compression for the first and second stage of compression, then the ratio of workdone on the first and second stages (W1/W2) with perfect intercoooing is given by
[A].

[B].

[C].

[D].

Answer: Option B

Explanation:

No answer description available for this question.

Question: For perfect intercooling in a three stage compressor,
[A].

[B].

[C].

p1p2 = p3p4

[D].

p1p3 = p2p4

Answer: Option A

Explanation:

No answer description available for this question.