Related Mcqs:

1. 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

2. 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

3. Fouling factor for a heat exchanger is given by (where, U1 = heat transfer co-efficient of dirty surface U2 = heat transfer co-efficient of clean surface) ?

   A. U1 – U2
   B. 1/U1 – 1/U2
   C. 1/U2 – 1/U1
   D. U2 – U1

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 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

6. 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. 1/2
   D. 4

7. LMTD correction factor which is to be applied for a cross-flow heat exchanger increases with increase in the number of shell passes. Its value for a single pass cross flow heat exchanger is __________________?

   A. 0
   B. 1
   C. > 1
   D. < 1

8. 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)

9. In a 1-1 concurrent heat exchanger, if the tube side fluid outlet temperature is equal to the shell side fluid outlet temperature, then the LMTD is_________________?

   A. ∞
   B. 0
   C. Equal to the difference between hot and cold fluids inlet temperature
   D. Equal to the difference between hot fluid inlet temperature and cold fluid outlet temperature

10. 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