Question

List five methods you can enhance heat transfer in a duct

Answer 1

Heat transfer is inversely proportional to the thermal resistance. Less the thermal resistance more is the heat transfer and vice-versa. So, heat transfer enhancement generally reduce the thermal resistance either by increasing the effective heat transfer surface area or by turbulence generation. A number of heat transfer enhancement techniques are being adopted by many industries after learning about the adverse effects of overheating of equipments. Some of the heat transfer enhancement techniques are as follows:-

1)Using a porous material inside the inner wall of duct. This method can increase the heat transfer rate with a pressure drop.

2) Using extended surfaces like fins. Fins increase the surface area for heat transfer thus by dumping the heat in its surroundings .

3)By providing a layer of insulation on the outer walls of duct. This increase the surface area for heat transfer.

4)By using various types of heat exchangers.

5)By using the smooth helical coil duct instead of straight duct. Study shows that the smooth helical coiled tube shows instead thermal performance of maximum 3.6 than the straight one.