In a heat exchanger, the rate of heat transfer from the hot fluid to the cold fluid

In case of parallel flow heat exchanger, the lowest temperature theoretically attainable by the hot fluid is __________ the outlet temperature of the cold fluid.

A

Equal to

B

More than

C

Less than

D

Either more or less than (depending upon the fluid)

Air is to be heated by condensing steam. Two heat exchangers are available (i) a shell and tube heat exchanger and (ii) a finned tube heat exchanger. Tube side heat transfer area are equal in both the cases. The recommended arrangement is

A

Finned tube heat exchanger with air inside and steam outside

B

Finned tube heat exchanger with air outside and steam inside

C

Shell and tube heat exchanger with air inside tubes and steam on shell side

D

Shell and tube heat exchanger with air on shell side and steam inside tubes

In a shell and tube heat exchanger, putting a longitudinal baffle across the shell, forces the shell side fluid to pass __________ through the heat exchanger.

A

Once

B

Twice

C

Thrice

D

Four times

A concentric double pipe heat exchanger as compared to the shell and tube heat exchanger for the same heat load requires

A

Less heating surface

B

More space

C

Lower maintenance cost

D

None of these

Parallel straight line pattern of temperature distribution for both hot and cold fluids is observed in case of heat exchanger of the type

A

Parallel flow with equal heat capacities

B

Counter flow with equal heat capacities

C

Counter flow with unequal heat capacities

D

Parallel flow with unequal heat capacities

In a parallel flow heat exchanger, if the outlet temperature of hot and cold fluids are the same, then the log mean temperature difference (LMTD) is

A

Minimum

B

Maximum

C

Zero

D

Infinity

For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area

A

Increases

B

Decreases

C

Remains constant

D

Passes through a maxima

Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the

A

Surrounding temperature

B

Average temperature of the fin

C

Temperature of the fin end

D

Constant temperature equal to that of the base

LMTD in case of counter flow heat exchanger as compared to parallel flow heat exchanger is

A

Higher

B

Lower

C

Same

D

Depends on the area of heat exchanger

If all the conditions and dimensions are same, then the ratio of velocity through the tubes of a double pass heat exchanger to that through the single pass heat exchanger is

A

1

B

2

C

$$\frac{1}{2}$$

D

4

In a heat exchanger, the rate of heat transfer from the hot fluid to the cold fluid

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