High-efficiency plate heat exchanger: Improving the heat transfer technology of high-efficiency plate heat exchangers

Release time:

2020-08-26 09:45

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1. It is necessary to improve the heat transfer coefficient of the high-efficiency plate heat exchanger

At the same time, increase the heat transfer coefficient on both sides of the plate and reduce the thermal resistance of fouling. Of course, plates with thermal conductivity must be selected, and the plate thickness should be reduced to improve the heat transfer of the high-efficiency plate heat exchanger. Heat coefficient.

(1) Improve the surface heat transfer coefficient of the plate. Because the corrugation of the plate heat exchanger causes the fluid to generate turbulence at a small flow rate (Reynolds number is 150), a higher surface heat transfer coefficient can be obtained. The heat transfer coefficient is related to the geometric structure of the plate corrugation and the flow state of the medium.

(2) Select austenitic stainless steel, titanium alloy, copper alloy, etc. to select plates with high thermal conductivity. Stainless steel has good thermal conductivity, with a thermal conductivity of about 14.4W/(mK), high strength, good stamping performance, and is not easily oxidized. The price is lower than titanium alloy and copper alloy. It is widely used in heating engineering, but it has chlorine resistance. Poor ion corrosion resistance.

(3) Reduce the thermal resistance of the fouling layer The key to reducing the thermal resistance of the fouling layer of a high-efficiency plate heat exchanger is to prevent plate fouling. When the fouling layer thickness is 1 mm, the heat transfer coefficient is reduced by about 10%. Therefore, attention must be paid to monitoring the water quality on both sides of the heat exchanger to prevent plate fouling and prevent debris in the water from adhering to the plate. Some heating units add chemicals to the heating medium to prevent water theft and corrosion of steel parts. Therefore, attention must be paid to the water quality and adhesives that cause debris to contaminate the heat exchanger plate. If there are viscous impurities in the water, special filters should be used for treatment. When choosing drugs, it is recommended to choose non-sticky drugs.

(4) Reduce the plate thickness The design thickness of the plate is irrelevant to its corrosion resistance, but it is related to the pressure-bearing capacity of the heat exchanger. Thicker plates can improve the pressure-bearing capacity of high-efficiency plate heat exchangers. When using a herringbone plate combination, adjacent plates are inverted, and the corrugations are in contact with each other, forming high-density and evenly distributed fulcrums. The corner and edge sealing structure of the plate has been gradually improved, so that the high-efficiency plate heat exchanger has good pressure resistance. The pressure-bearing capacity of household detachable plate heat exchangers has reached 2.5 MPa. The thickness of the plate has a great influence on the heat transfer coefficient. If the thickness is reduced by 0.1 mm, the total heat transfer coefficient of the symmetrical plate heat exchanger will increase by about 600 W/(MK), and the asymmetrical type will increase by about 500 W/(mK). Under the premise of meeting the pressure-bearing capacity of the high-efficiency plate heat exchanger, the thickness of the plate should be as small as possible.

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