Heat Transfer: Practical Problems

1.      An insulation tip mean k = 0; or dT/dx=0

2.      How can we find the direction of fluid flow in a metal pipe by the concept of heat transfer?

     Ans: if we heat the pipe, and measure temperature at two point in different sides, then fluid will be flowing in the direction of high temperature.

3.      Mineral oil is filled in between the narrow gap of 2 horizontal smooth plates which are maintained at constant temperature. The heat flux in 2^nd case will be more than/less than or equal to 39 W/m², explain.

Ans: in second case. heat flux will be less because it will have only conduction while in 1st we have both conduction and convection.

4. What will be more effective way of heating a room 1 kW heater or refrigerator having power consumption of 1 kW?
Ans: 1 kW heater will give 1 kW heat while 1 kW power refrigerator will give more heat to the room.

5.      In a process at steady state, an ideal fin is at a base temperature of 100 °C, the temperature at the base for the real fin will be less, more or same, explain?

Ans: the ideal fin transfers more heat than a real fin, in order to transfer same heat the base temperature should be more for a real fin.

6.      If we open the refrigerator and its radiator portion outside the room, will it work as air conditioner? Explain

7.      In air cooler, if water and air are at same temperature, then also will there be cooling? Explain.

8.      In an oil water finned tube heat exchanger, which fluid should be passed through fin side and why?

9.      Can we transfer heat from low temperature to high temperature, explain?

10.         LMTD profile for i) 1, 2 shells & tube heat exchanger and ii) steam condensation in double pipe HE.