In case of a shell and tube heat exchanger, the minimum and maximum baffle spacing is respectively (where, D = inside diameter of the shell)

The centre to centre distance between two consecutive baffles in a shell and tube heat exchanger is called the baffle pitch or baffle spacing, which is more than $${\frac{1}{5}^{{\text{th}}}}$$ the I.D. of the shell. Which of the following is not a function of the baffles?

A

To increase the residence time of shell side fluid

B

To provide support to the tube bundle

C

To reduce the induced vibration in the tubes

D

To increase the tube side heat transfer co-efficient by inducing turbulence

Plate type heat exchangers have less surface area as compared to a similar Shell and Tube heat exchanger. A Shell and Tube Heat Exchanger of equivalent area weigh six-seven times less than a Plate Type heat exchanger.

A

True

B

False

If 'D' is the inside diameter of the shell of a shell and tube heat exchanger, then the baffle spacing is usually in the range of

A

D/2 or minimum 2" to 5D

B

D/5 or minimum 2" to 5D

C

D/5 or minimum 2" to D

D

None of these

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

Minimum recommended baffle spacing in a shell and tube heat exchanger is about (where, D = shell diameter)

A

0.2 D

B

0.5 D

C

0.66 D

D

0.80 D

Minimum recommended baffle spacing in a shell and tube heat exchanger is about (where, D = shell diameter )

A

0.2 D

B

0.5 D

C

0.66 D

D

0.80 D

A single pass shell and tube heat exchanger, consisting of a bundle of 100 tubes (inner diameter 25 mm and thickness 2 mm) is used for heating 28 kg/s of water from 25 degree Celsius to 75 degree Celsius with the help of a steam condensing at atmospheric pressure on the shell side with condensing heat transfer coefficient 5000 W/m2 degree. Make calculation for overall heat transfer coefficient based on the inner area. Take fouling factor on the water side to be 0.002 m2 degree/W per tube and neglect effect of fouling factor on the shell side and thermal resistance of the tube wall

A

647.46 W/m2 degree

B

747.46 W/m2 degree

C

847.46 W/m2 degree

D

947.46 W/m2 degree

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 counter flow heat exchanger, water flowing through a tube of 10 cm inner diameter is heated by steam condensing on the outside of the tube. The convective film coefficient on the water and steam side are estimated to be 12000 and 20000 k J/m2 hr degree. Neglecting tube thickness and its resistance to heat flow, workout the overall heat transfer coefficient for the heat exchanger

A

4500 k J/m2 hr degree

B

5500 k J/m2 hr degree

C

6500 k J/m2 hr degree

D

7500 k J/m2 hr degree

Steam is to be condensed in a shell and tube heat exchanger, 5 m long with a shell diameter of 1 m. Cooling water is to be used for removing the heat. Heat transfer co-efficient for the cooling water, whether on shell side or tube side is the same. The best arrangement is

A

Vertical heat exchanger with steam on tube side

B

Vertical heat exchanger with steam on shell side

C

Horizontal heat exchanger with steam on tube side

D

Horizontal heat exchanger with steam on shell side

In case of a shell and tube heat exchanger, the minimum and maximum baffle spacing is respectively (where, D = inside diameter of the shell)

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