Selection in the selection and design of heat exchanger plate
Under general working conditions, the most popular choice is the heat exchanger plate with symmetrical flow channels, because when the volumetric flow rates of the two medium fluids are approximately the same, it is more reasonable to choose the isochronous arrangement; and when the two sides of the plate heat exchanger When there is a large difference in medium and fluid flow, then the fluid on the side with the small flow should be selected as much as possible for multi-flow layout. The phase change side of the plate heat exchanger is generally a single process. Multi-process plate heat exchangers, if it is not a special need, generally use the same number of channels in the plate heat exchanger for the same liquid.
In the case of a certain pressure drop, the multi-process arrangement will reduce the corresponding pressure drop on each side, so that the flow rate will be lower, and the corresponding heat exchange efficiency will also decrease. In addition, the multi-process arrangement of unequal processes is also one of the important factors that the average heat transfer temperature difference becomes smaller, and should be avoided or reduced as much as possible.
In recent years, with the diversification of the application conditions of plate heat exchangers, domestic plate heat exchangers have appeared in the form of asymmetric channels, and more foreign ones have adopted the plate combination form of "thermal mixing", that is, allowing heat- The problem of mismatch between the flow rate and the pressure drop, which also saves the heat exchange area.
In the case of a certain pressure drop, the multi-process arrangement will reduce the corresponding pressure drop on each side, so that the flow rate will be lower, and the corresponding heat exchange efficiency will also decrease. In addition, the multi-process arrangement of unequal processes is also one of the important factors that the average heat transfer temperature difference becomes smaller, and should be avoided or reduced as much as possible.
In recent years, with the diversification of the application conditions of plate heat exchangers, domestic plate heat exchangers have appeared in the form of asymmetric channels, and more foreign ones have adopted the plate combination form of "thermal mixing", that is, allowing heat- The problem of mismatch between the flow rate and the pressure drop, which also saves the heat exchange area.