What is the effect of adding upper fins to the finned tube?

Why use finned tubes, and what effect can adding fins to the original surface play? Due to the convective heat exchange between the two media inside and outside the tube, the heat transfer coefficient of the water in the tube is dozens or even hundreds of times that of the air outside the tube, so fins are added outside the tube to make the original air-side heat transfer coefficient. The heat exchange area is greatly expanded, which makes up for the low heat exchange coefficient of the air outside the tube.

The main applications of finned tubes are:

1. During the heat transfer process, the heat transfer thermal resistance of the fluids on both sides is asymmetrical, one side has a large thermal resistance and one side has a small thermal resistance, and fins should be added on the side with a large thermal resistance. For example: boiler economizer, air cooler, steam generator, etc.

2. If the heat transfer coefficient on both sides of the tube is very small, in order to strengthen the heat transfer, fins should be installed on both sides at the same time. For example: air preheater.

3. When the heat transfer coefficients on both sides of the tube are large, it is not necessary to use finned tubes, but threaded tubes or corrugated tubes can be used. For example: power plant condensers.

The finned tubes are classified in terms of use and structure, and can be divided into finned tubes for heat exchange with air, finned tubes for heat exchange with flue gas, finned tubes for heat exchange with organic media or refrigeration media, and finned tubes for heat exchange with air. Finned tubes for heat dissipation of electrical components.