How to improve the efficiency of plate heat exchangers.
Time: 2023-03-14
To improve the heat transfer coefficient of the heat exchanger, the only way to effectively improve the heat transfer coefficient of the heat exchanger is to simultaneously increase the heat transfer coefficient of the surface on both sides of the plate, reduce the thermal resistance of the dirt layer, select the plate with high thermal conductivity, and reduce the thickness of the plate.
explain:
1. Because the ripple of plate heat exchanger can make the fluid produce turbulence at a small flow rate, a higher surface heat transfer coefficient can be obtained. The surface heat transfer coefficient is related to the geometric structure of the plate ripple and the flow state of the medium. The waveform of the plate includes herringbone, straight, spherical, etc. After years of research and experiments, it is found that the herringbone plate with triangular corrugated section has a higher surface heat transfer coefficient, and the larger the included angle of the corrugation is, the higher the medium flow rate in the flow channel between the plates is, and the greater the surface heat transfer coefficient is.
The key to reducing the thermal resistance of the fouling layer in the heat exchanger is to prevent plate fouling. The heat transfer coefficient decreases by about 10% when the plate fouling thickness is 1mm. Therefore, it is necessary to pay attention to monitoring the water quality on both the hot and cold sides of the heat exchanger to prevent plate fouling and prevent impurities from adhering to the plates in the water. Some heating units add chemicals to the heating medium to prevent water theft and corrosion of steel components. Therefore, it is necessary to pay attention to water quality and adhesives that can cause impurities to contaminate the heat exchanger plates. If there are viscous impurities in the water, a dedicated filter should be used for treatment. When selecting agents, it is advisable to choose non viscous agents.
3. The material of the plate can be stainless steel, titanium alloy, copper alloy, etc. Stainless steel has good thermal conductivity, with a thermal conductivity of about 14.4W/(m • K), high strength, good stamping performance, and is not easily oxidized. Its price is lower than titanium and copper alloys, and it is most commonly used in heating engineering, but its ability to resist chloride ion corrosion is poor.
