Related Mcqs:

1. 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

2. The inside heat transfer co-efficient in case of turbulent flow of liquid in the tube side in a 1-2 shell and tube heat exchanger is increased by ______________ times, when the number of tube passes is increased to 8?

   A. 20.8
   B. 40.8
   C. 40.4
   D. 20.4

3. In a shell and tube heat exchanger, the tube side heat transfer co-efficient just at the entrance of the tube is_________________?

   A. Infinity
   B. Zero
   C. Same as average heat transfer co-efficient for tube side
   D. None of these

4. 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

5. The overall heat transfer co-efficient for a shell and tube heat exchanger for clean surfaces is U0 = 400 W/m2.K. The fouling factor after one year of operation is found to be hd0 = 2000 W/m2.K. The overall heat transfer co-efficient at this time is _____________________?

   A. 1200 W/m2.K
   B. 894 W/m2.K
   C. 333 W/m2.K
   D. 287 W/m2.K

6. 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

7. A 10 cm dia steam pipe, carrying steam at 180°C, is covered with an insulation (conductivity = 0.6 W/m.°C). It losses heat to the surroundings at 30°C. Assume a heat transfer co-efficient of 0.8 W/m2.°C for heat transfer from surface to the surroundings. Neglect wall resistance of the pipe and film resistance of steam. If the insulation thickness is 2 cms, the rate of heat loss from this insulated pipe will be__________________?

   A. Greater than that for un-insulated steam pipe
   B. Less than that of the un-insulated steam pipe
   C. Equal to that of the un-insulated steam pipe
   D. Less than the steam pipe with 5 cms insulation

8. A fluid is flowing inside the inner tube of a double pipe heat exchanger with diameter ‘d’. For a fixed mass flow rate, the tube side heat transfer co-efficient for turbulent flow conditions is proportional to_____________________?

   A. d0.8
   B. d-0.2
   C. d-1
   D. d-1.8

9. The advantage of using a 1 – 2 shell and tube heat exchanger over a 1 – 1 shell and tube heat exchanger is_________________?

   A. Lower tube side pressure drop
   B. Lower shell side pressure drop
   C. Higher tube side heat transfer co-efficient
   D. Higher shell side heat transfer co-efficient

10. For turbulent flow in a tube, the heat transfer co-efficient is obtained from the Dittus- Boelter correlation. If the tube diameter is halved and the flow rate is doubled, then the heat transfer co-efficient will change by a factor of________________?

    A. 1
    B. 1.74
    C. 6.1
    D. 37