Plate heat exchangers are ideal equipment for liquid-liquid and liquid-vapor heat exchange. It has the characteristics of high heat exchange efficiency, low heat loss, compact and lightweight structure, small footprint, wide application and long service life. With the diversification of the application conditions of plate heat exchangers, domestic heat exchangers have appeared in the form of asymmetric channels. Foreign countries use the "thermal mixing" plate combination form, which allows the mismatch between heat-flow-pressure drop, and thus saves heat exchange area.
(1) When the volumetric flow rates of the two heat exchange medium fluids are roughly the same, it is reasonable to choose an isochronous arrangement. Under such working conditions, plate heat exchangers with symmetrical runners are often chosen. When the flow rate difference between the two sides of the board change is large, the side with the small flow rate should choose the multi-process layout as much as possible.
(2) In the case of a certain pressure drop, the multi-process arrangement will reduce the corresponding pressure drop on each side, thereby reducing the flow rate and the heat exchange efficiency. The multi-process layout of different processes is also one of the important factors that the average heat transfer temperature difference becomes smaller. We should avoid or reduce as much as possible.