A single pass air heater is connected to a two pass unit. For the air flow rate and other conditions remaining the same, the film heat transfer co-efficient for air will vary in the ratio of_________________?

Related Mcqs:

1. Heat transfer co-efficient, hG(Kcal/hr.m2 .°C) and mass velocity of air, G (kg/hr.m2 ) for air flow parallel to the surface in case of constant drying rate in batch drying is related as hG = 0.0176G0.8. But when the flow of air perpendicular to the surface is encountered, this equation changes to ____________________?

   A. hG = 1.004G0.37
   B. 1.004G0.8
   C. hG = 0.0176G0.37
   D. 0.0176G1.37

2. In a shell and tube heat exchanger, the overall heat transfer co-efficient is proportional to the tube side (volumetric flow rate)0.8. This is valid, only when the ratio of the tube side film resistance to the total resistance is almost equal to____________________?

   A. ∞
   B. 1
   C. 20.8
   D. 2

3. Overall mass transfer co-efficient in case of absorption of __________ in water is based on the gas film co-efficient only, as the mass transfer process is gas film (phase) controlling ?

   A. CO2
   B. SO2
   C. NH3
   D. None of these

4. If a single tube pass heat exchanger is converted to two passes; for the same flow rate, the pressure drop per unit length in tube side will _____________ times?

   A. Increase by 1.8
   B. Decrease by 22
   C. Increase by 21.6
   D. None of these

5. Heat transfer co-efficient for a horizontal condenser as compared to a vertical condenser operating under similar conditions is_______________?

   A. Same
   B. Less
   C. About 3 times
   D. About 0.33 times

6. In case of a shell and tube heat exchanger, the effect of L/D on inside film heat transfer coefficient (hi) vanishes after a Reynold number of_____________?

   A. 1000
   B. 3000
   C. 5000
   D. 10000

7. Tube side pressure drop in a 1-2 heat exchanger (for turbulent flow of fluids through the tubes) is about __________ times, that in a 1-1 heat exchanger having the same size & number of tubes and operated at the same liquid flow rate ?

   A. 2
   B. ½
   C. 4
   D. 8

8. Poisson’s ratio of a material is the ratio of unit lateral strain to the unit axial elongation within its elastic limit. The value of Poisson’s ratio for structural and pressure vessel steel may be taken as ____________________?

   A. 0.01
   B. 0.3
   C. 0.75
   D. 0.95

9. Shell side heat transfer co-efficient in case of square pitch as compared to the triangular pitch under similar condition of fluid flow and tube size is_____________?

   A. More
   B. Same
   C. Less
   D. Twice

10. Tube side heat transfer co-efficient for turbulent flow of liquid through tubes is proportional to___________________?

    A. G0.2
    B. G0.5
    C. G0.8
    D. G1.5