After understanding the principles and functions of the finned tube, there are the following principles for the choice of finned tube:
(1) If the heat transfer coefficients on both sides of the tube are very different, fins should be installed on the side with the smaller heat transfer coefficient.
Example 1: Boiler economizer, with water flowing inside the tube, flue gas flowing out of the tube, and fins should be used on the flue gas side.
Example 2: In an air cooler, liquid flows in the tube and air flows out of the tube. The fins should be added on the air side. Example 3: In the steam generator, water is boiled inside the tube, and flue gas flows outside the tube. The fins should be added to the flue gas side. It should be noted that in the design, the side with the smaller heat transfer coefficient should be placed outside the tube to facilitate the installation of fins.
(2) If the heat transfer coefficients on both sides of the tube are very small, in order to enhance heat transfer, fins should be installed on both sides at the same time. If there are structural difficulties, no fins should be added on both sides. In this case, adding fins on only one side will not have a significant effect on the increase in heat transfer.
Example 1: The traditional tubular air preheater uses air inside the tube and flue gas outside the tube. Because it is gas-to-gas heat transfer, the heat transfer coefficients on both sides are very low, and it is very difficult to add fins in the tube, so we had to use a bare tube.
Example 2: Heat pipe type air preheater, although the flue gas still heats the air, because the flue gas and air flow outside the tube, finned tubes can be conveniently used on both the flue gas side and the air side to transfer heat greatly increase.
(3) If the heat transfer coefficients on both sides of the tube are large, there is no need to use finned tubes.
Example 1: Water/water heat exchanger. When hot water is used to heat cold water, the heat transfer coefficients on both sides are high enough, so there is no need to use finned tubes. However, in order to further enhance heat transfer, a threaded tube or a corrugated tube can be used instead of a light tube.
Example 2: In the condenser of a power plant, the outside of the tube is the condensation of water vapor, and the inside of the tube is water. The heat transfer coefficients on both sides are very high, under normal circumstances, finned tubes are not needed.
Specific finned tube introduction:
The higher the heat transfer value of the spiral finned tube in the thermal performance requirements, the better, which can indicate that the heat dissipation performance of the equipment is good, so that the heat dissipation of the product can be effectively improved, and the heat transfer coefficient of the equipment can be Increase the heat dissipation area of the outer wall to increase the flow speed of the surrounding air.
The installation of the spiral finned tube is relatively simple. The tube length of the finned tube in the equipment can reach about 6 meters. The connection points can be reduced during the installation process, so that the installation will become more rapid and Economical, this can also greatly reduce the probability of water leakage.
Spiral finned tube can be applied in a wide range. The most important thing is that it can withstand relatively high pressure to a certain extent. Therefore, the service life of spiral finned tube is longer. The spiral finned tube will be high frequency The power source is the main heat source.
The helical finned tube has a very high heat transfer efficiency, and to a certain extent the heat dissipation area is very large, so it can be applied to a wide range of positions. The most important thing about the spiral finned tube is that it can withstand higher pressure, so the spiral fin The finned tube has a longer service life, and the spiral finned tube uses high-frequency power as the main heat source.
The helical finned tube has a very good overall heat transfer efficiency. If you compare it with other finned tube products, the heat transfer efficiency should be high. Compared with the light tube, the entire heat transfer The efficiency is about four times higher.
For the integral spiral fin tube, the entire fin is integrally rolled with the base tube, but other common fin tubes are directly welded to the surface of the base tube. Therefore, on the welding surface, The phenomenon of thermal resistance is relatively easy and often occurs, which causes its heat exchange effect to be seriously affected.
Because the overall spiral finned tube is better than ordinary finned tubes in the ability to resist dust accumulation, because of its high-quality performance characteristics, the effect of use has been significantly improved and improved. Spiral finned tubes In the process of production, it is mainly manufactured by multi-roller rolling. It has a relatively high smoothness on the surface, and the overall density of the structure is also very high. Between the fin tube and the base tube The height is relatively natural, so its anti-corrosion performance has been significantly improved.
The advantage of the spiral finned tube is to increase the heat exchange area with a smaller specific heat capacity, so that the heat exchange efficiency reaches the theoretical maximum value. The area of the finned tube is several times or even ten times that of the ordinary light tube. At this time, not only the heat exchange efficiency of the equipment is increased, but also the heat exchange cost is greatly reduced.
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