Finned tube heat exchanger is one of the most widely used heat transfer equipment in gas and liquid heat exchangers. It achieves the purpose of strengthening heat transfer by adding fins on ordinary base tubes.
The base tube can be filled with steel pipe; Stainless steel tube; Copper tube, etc. Fins can also be made of steel; Stainless steel belt, copper strip, aluminum strip, etc.
The finned heat exchanger is mainly used for air heating in the drying system, which is the main equipment in the hot air device.
Heat medium of heat exchanger can be steam or hot water, also can be heat conduction oil, steam pressure is generally not more than 0.8 Mpa, hot air temperature under 150 ℃
The finned tube exchanger is composed of three rows of spiral fin tubes.
The processing technology of SRZ fin tube bundle is anti-0.5 *10 mm steel belt with mechanical winding method, Wrapping around 18 mm seamless steel tube, then doing hot dip galvanized, also can use stainless steel pipe and stainless steel belt made of full stainless steel heat dissipation
The SRL radiator is a finned radiator with steel tube and aluminum strip, and its unit length is larger than SRZ.
The finned heat exchanger is characterized by a large and tight contact surface of the heat dissipation fin and the heat dissipation tube. The heat transfer performance is good and stable, and the air is small by resistance.
Steam or hot water passes through the tube, and the heat passes through the air between the fins and passes through the wings to achieve the effect of heating and cooling the air.
Generally, the spacing and height of finned tube heat exchanger mainly affect the wing ratio, and the wing ratio has a great relationship with the film heat transfer coefficient of the inner and outer media.
If the coefficient of heat transfer between the inner and outer membrane of the tube is very different, it should choose the finned tube with larger wing ratio, such as steam heating air.
When there is a phase change in the side medium, the difference of heat transfer coefficient is larger, such as the exchange of cold and hot air, and the finned tube heat exchanger can be used when the hot air drops below the dew point.
In the absence of phase change in the heat exchange between air and air, or the heat exchange between water and water, it is usually appropriate to use a bare tube. Of course, the low-fin tube can also be used, because it belongs to the weak heat coefficient, and it is effective to strengthen any side of it.
However, it is not obvious that the excessive wing ratio is not obvious, and the best internal and external contact area is also strengthened, which can be used with threaded or grooved tubes.
The blade spacing of fins is mainly concerned with accumulation of ash, dust, easy cleaning and other factors. Meanwhile, it is necessary to strictly meet the requirements of equipment on pressure drop.
When arranging, the distance between tube and tube is not easy to be too large. Generally, >1mm is suitable for cloth tube.
In the process of heat transfer, the air is mainly involved in the heat transfer between the fins and the two sides of the finned tube heat exchanger.
There is only a small amount of radiative heat transfer in the middle part of the two fin tubes, and the heat transfer effect is not obvious. Because of the wingless film, there is no resistance and the air penetrates easily.
In the process of air heating, cold air will without heat and fin has hot air heating and passing through the middle, but reduces the heat transfer effect, compared with the foreign finned tube heat exchanger, tube spacing is bigger than fin diameter only 0.5 mm, visible finned tube arrangement, the importance of tube spacing