中文(简体) 1. [characteristics and application scope of plate heat exchanger]
Plate heat exchanger is one of the widely used heat transfer equipment. It has the characteristics of high heat transfer efficiency, compact structure, small floor area, convenient installation, maintenance and combination. Widely used in: electric power, petroleum, chemical industry, metallurgy, machinery, light industry, food, medicine, electric power, coating, shipbuilding, electromechanical, textile, papermaking, heating and other industrial departments.
2. [heat transfer mechanism of plate heat exchanger]
The heat transfer mechanism of plate heat exchanger is based on heat transfer mechanism and thermodynamic law: "heat is always spontaneously transferred from high-temperature object to low-temperature object. If there is a temperature difference between the two fluids, heat transfer must be carried out". In the forced convection heat transfer process of two temperature difference fluids, the heat transfer rate reaches 92% due to the optimization of corrugated structure on the surface of the heat exchange plate. Even if the fluid velocity is lower than the Reynolds criterion, the fluid motion between plates is three-dimensional, which promotes the formation of severe turbulence, reduces the thermal resistance of the boundary layer and improves the heat transfer efficiency.
3. [performance characteristics of plate heat exchanger]
At present, the plate heat exchanger has been used in small refrigeration (cooling water) equipment, and its application will be further expanded. This is mainly due to the excellent heat exchange performance, small volume and light weight of the plate heat exchanger, as well as the continuous improvement of the safety and reliability of the plate heat exchanger. Generally speaking, the practical application effect is good. However, there are also some problems.
Due to the strong heat exchange capacity of plate heat exchanger (its heat exchange coefficient is several times higher than that of conventional heat exchanger, and the heat exchange area per unit volume is large), small size and light weight. Therefore, it is favored by researchers and users. However, the poor pressure resistance and sealing performance of plate heat exchanger restrict the application of plate heat exchanger in engineering. In the past, plate heat exchanger was mainly used for working medium cleaning, low working pressure and leakage requirements Equipment that is not strict and has little impact on the environment and working medium after leakage, such as civil hot water transmission system, steam hot water exchange system, etc.
At present, plate heat exchangers are mainly used for refrigeration equipment, mainly some small equipment, mainly imported brazed plate heat exchangers. It is theoretically feasible to use a separate plate heat exchanger on the condenser and evaporator of large chillers, but there is no relevant report. In other words, people still have some concerns about the further promotion and application of plate heat exchanger in the refrigeration industry, and its safety, reliability and related problems need to be further solved.
