In fact, as long as the heat transfer coefficients of the surfaces on both sides of the cold and hot are raised at the same time, and the level of dirt must be reduced, the plate with a high thermal conductivity is selected, and the thickness of the plate must be reduced again, so that the plate can be effectively changed. Heat transfer coefficient of the heater.
First, the surface heat transfer coefficient of the rising plate Because the ripple of the plate plate heat exchanger can make the fluid turbulent at a small flow rate (reynolds number 150), it can obtain a higher surface heat transfer coefficient, surface heat transfer The thermal coefficient is related to the geometry of the plate corrugations and the flow state of the medium. The waveform of the plate includes herringbone, straight, spherical, and so on. The shape of the corrugated section is triangular (sinusoidal surface has a large heat transfer coefficient, a small pressure drop, and uniform stress distribution under compression, but is difficult to process?) The herringbone plate has a high surface heat transfer coefficient, and the corrugated clamp The larger the angle, the higher the medium velocity in the flow channel between the plates, and the larger the surface heat transfer coefficient.
Second, reducing the thermal resistance of the dirt layer The key to reducing 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, we must pay attention to the water quality on both sides of the hot and cold to prevent the plate from scaling and prevent water from adhering to the plate. Some heating units are used to prevent water theft and corrosion of steel parts, and add agents to the heating medium, so we must pay attention to water quality and adhesives that cause debris to stick to the plates. If there are sticky debris in the water, it should be treated with a filter. When choosing, should choose non-sticky medicine.
Third, the selection of high thermal conductivity plate material can choose austenitic stainless steel, titanium alloy, copper alloy and so on. Stainless steel has good thermal conductivity, thermal conductivity of about 14.4 W / (mK), high strength, good stamping performance, not easy to be oxidized, lower price than titanium alloy and copper alloy, it is used a lot in heating engineering, but its resistance to chlorine Poor ability to ion corrosion.