**The Design Calculation Of Plate Heat Exchanger**

In recent years, China's central heating industry has developed rapidly, and plate heat exchangers have been used in many heat exchange fields.The heat exchange area of the plate heat exchanger produced by the manufacturer of the plate heat exchanger is at least 0.05 square and the maximum is 2 square. The maximum working pressure that can be received is 2.0Mpa, and the maximum working temperature is 250 degrees.At the same time, various new board types are being actively developed. A complete unit has been developed that assembles heat exchangers, circulating water pumps and other auxiliary equipment.

The design calculation method of plate heat exchanger can be classified into two categories. (1) We know the thermal and hydraulic characteristics of the plate heat exchanger expressed by the criterion equation, first select the plate type and the proposed flow rate between the plates, and then calculate the convective heat release coefficient and total heat transfer of the hot fluid and the cold fluid coefficient. Through several trial calculations, the required number of plates, flow combination and resistance loss can be obtained.(2) It is known to express the relationship between the plate-to-plate flow rate and the heat transfer coefficient of a plate heat exchanger using graphs or tables, first find out the heat transfer coefficient under design conditions, and then calculate the required number of plates, flow combination and resistance loss. There is no principle difference between the two methods, but under the current conditions, the first method is better. Because in the second method, because most of the plate heat exchanger performance test benches built so far have a very small change in fluid temperature, the relationship between the heat transfer coefficient and the flow rate does not reflect the effect of fluid temperature.