Plate heat exchanger is a kind of high-efficiency heat exchanger made of a series of metal sheets with a certain corrugated shape. Plate heat exchangers are ideal equipment for liquid-liquid, liquid-vapor heat exchange. Improving the heat transfer technology of the plate heat exchanger needs to increase the surface heat transfer coefficient of the cold and hot sides of the plate, reduce the thermal resistance of the dirt layer, choose a plate with high thermal conductivity and reduce the thickness of the plate.
(1) Increase the surface heat transfer coefficient of the plate. Since the corrugation of the plate-type plate heat exchanger can make the fluid generate turbulence at a small flow rate (reynolds number 150), a higher surface heat transfer coefficient can be obtained. The surface heat transfer coefficient is related to the geometry of the plate corrugation and the flow state of the medium. The chevron plate has a higher surface heat transfer coefficient. The larger the included angle of the corrugation, the higher the medium flow velocity in the flow channel between the plates, and the larger the surface heat transfer coefficient.
(2) Reduce the thermal resistance of the dirt layer. The key to the thermal resistance of the dirt layer of the plate heat exchanger is to prevent plate fouling. When the thickness of the plate is 1 mm, the heat transfer coefficient is reduced by about 10%. Therefore, it is necessary to pay attention to monitoring the water quality on both sides of the plate heat exchanger to prevent the plate from scaling and prevent water from adhering to the plate.
(3) Use a plate with high thermal conductivity. The plate material can be selected from austenitic stainless steel, titanium alloy and copper alloy. Stainless steel has good thermal conductivity, thermal conductivity of about 14.4 W / (m.K), high strength, good stamping performance, and is not easily oxidized.