For ammonia refrigerating systems, the tubes of a shell and tube condenser are made of

In a shell and tube heat exchanger for a given heat transfer surface area, smaller diameter tubes are favoured as compared to larger diameter ones ; because the smaller diameter tubes

A

Are easier to clean

B

Are less prone to fouling

C

Can be fitted into a smaller shell diameter hence the cost of the heat exchanger would be less

D

None of these

In case of a shell and tube heat exchanger, the minimum shell thickness for carbon steel (inclusive of corrosion allowance) depends on shell diameter and is in the range of __________ mm.

A

3-5

B

5-11

C

8-15

D

12-18

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

In a multipass shell and tube heat exchanger, the problem of differential expansion between the shell and tube passes is taken care of by using a

A

U-bend

B

Floating head tube sheet

C

Either A or B

D

Neither A nor B

In a shell and tube heat exchanger having square pitch, the shell side equivalent diameter is given by (where, P = pitch, d = outside diameter of the tube)

A

$$\frac{{4\left( {{{\text{p}}^2} - \pi {{\text{d}}^2}/4} \right)}}{{\pi {\text{d}}}}$$

B

$$\frac{{{{\text{p}}^2} - \pi {{\text{d}}^2}/4}}{{\pi {\text{d}}}}$$

C

$$\frac{{4{{\text{p}}^2}}}{{\pi {\text{d}}}}$$

D

$$\frac{{\pi {\text{d}}}}{{4{{\text{p}}^2}}}$$

Ratio of tube length to shell diameter for a shell and tube heat exchanger is

A

8 : 1 to 12 : 1 for both liquid-liquid and gas-gas heat exchangers

B

4 : 1 to 8 : 1 for liquid-liquid exchanger

C

Both B & C

The ratio of tube length to shell diameter in case of liquid shell and tube heat exchanger ranges from

A

2 to 3

B

3 to 5

C

4 to 8

D

6 to 12

For the same heat load and mass flow rate in the tube side of a shell and tube heat exchanger, one may use multipass on the tube side, because it

A

Decreases the pressure drop

B

Decreases the outlet temperature of cooling medium

C

Increases the overall heat transfer coefficient

D

None of these

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 most of the shell and tube heat exchangers, the tube pitch is generally __________ the tube diameter.

A

Less than

B

1.25-1.50 times

C

2.5 times

D

One-fourth of

For ammonia refrigerating systems, the tubes of a shell and tube condenser are made of

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