Mode of heat transfer involved in the cooling of air cooled internal combustion engine is_________________?

A. Conduction
B. Natural convection
C. Forced convection
D. None of these

Which is the most suitable for the concentration of foamy & frothy liquors ?

A. Agitated film evaporator
B. Long tube vertical evaporator
C. Open pan evaporator
D. None of these

Heat exchangers operating, when the asymptotic range is reached, ?

A. Provide very large heat transfer co-efficient
B. Results in making part of the heating surface inactive
C. Results in abruptly increased velocity
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 evaporators, lowering the feed temperature_______________?

A. Increases the heating area required
B. Reduces the economy
C. Both A. and B.
D. Decreases the heating area required

Economy of a multiple effect evaporator is not influenced much by the_______________________?

A. Boiling point elevations
B. Temperature of the feed
C. Rate of heat transfer
D. Ratio of the weight of the thin liquor to thick liquor

Prandtl and Reynold’s analogies are identical for Prandtl number value of__________________?

A. 0
B. 0.5
C. 1
D. 5

Increasing the liquor level in the evaporator results in the_______________?

A. Decreased capacity
B. Increase in liquor film co-efficient
C. Decreased effect of hydrostatic head
D. Increased true temperature drop

A cube, sphere & a thin circular plate (all having same mass and made of same material) are all heated to 300°C and allowed to cool in natural air. Which one will cool the slowest ?

A. Cube
B. Plate
C. Sphere
D. All will cool at the same rate

The heat flux (from outside to inside) across an insulating wall with thermal conductivity, K = 0.04 W/m.°K and thickness 0.16m is 10 W/m2. The temperature of the inside wall is – 5°C. The outside wall temperature is___________________?

A. 25°C
B. 30°C
C. 35°C
D. 40°C