Hofmann (Beijing) Engineering Technology Co.,Ltd
Add:6F, East International Building, No.2 DongZhiMen Outside Street, DongCheng District, Beijing
1 improve heat transfer efficiency
The plate heat exchanger is a heat transfer heat exchanger. The hot and cold fluid transfers heat through the heat exchanger plate, and the fluid is in direct contact with the plate. The heat transfer mode is heat conduction and convection heat transfer. The key to improving the heat transfer efficiency of plate heat exchangers is to increase the heat transfer coefficient and the logarithmic mean temperature difference.
1 Improve the heat transfer coefficient of the heat exchanger: Only increase the surface heat transfer coefficient on both sides of the plate and heat, reduce the thermal resistance of the fouling layer, select the plate with high thermal conductivity, reduce the thickness of the plate, and effectively improve the change. Heat transfer coefficient of the heat exchanger.
a. Increase the surface heat transfer coefficient of the sheet
Since the corrugation of the plate heat exchanger enables the fluid to generate turbulence at a small flow rate (Reynolds number - 150), a higher surface heat transfer coefficient, surface heat transfer coefficient and plate corrugation geometry and medium can be obtained. The state of flow is related. The waveform of the plate includes a herringbone shape, a straight shape, a spherical shape, and the like. After years of research and experiments, it is found that the shape of the corrugated section is triangular (the sinusoidal surface has a large heat transfer coefficient, the pressure drop is small, the stress distribution is uniform under pressure, but the processing is difficult?), and the herringbone plate has a high surface pass. The thermal coefficient, and the larger the angle of the corrugation, the higher the medium flow velocity in the flow channel between the plates, and the greater the surface heat transfer coefficient.
b. Reduce the thermal resistance of the dirt layer
The key to reducing the thermal resistance of the fouling layer of the heat exchanger is to prevent scaling of the sheet. When the sheet scale is 1 mm thick, 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 heat exchanger to prevent scaling of the plates and to prevent the inclusion of impurities in the water on the plates. Some heating units add chemicals to the heating medium in order to prevent water theft and corrosion of steel parts. Therefore, it is necessary to pay attention to the water and the impurities causing the impurities to contaminate the heat exchanger plates. If there is sticky debris in the water, it should be treated with a special filter. When using a drug, it is advisable to choose a non-stick agent.
c. Use a plate with high thermal conductivity
The plate material can be selected from austenitic stainless steel, titanium alloy, copper alloy, and the like. Stainless steel has good thermal conductivity, thermal conductivity of about 14.4 W / (m · K), high strength, good stamping performance, not easy to be oxidized, the price is lower than titanium alloy and copper alloy, and it is used in heating engineering, but its Poor resistance to chloride ion corrosion.