Heat exchanger plate

Plate type selection of plate heat exchanger

The plate type or corrugated type shall be determined according to the actual needs of heat exchange occasions. For the case of large flow and small allowable pressure drop, the plate type with small resistance shall be selected, on the contrary, the plate type with large resistance shall be selected. According to the fluid pressure and temperature, determine whether to choose the detachable type or the brazed type. When determining the plate type, the plate with too small single plate area should not be selected to avoid too many plates, small flow velocity between plates and too low heat transfer coefficient. This problem should be paid more attention to larger heat exchangers.

Selection of process and runner

Flow refers to a group of parallel flow channels in the same flow direction of a medium in the plate heat exchanger, and the flow channel refers to the medium flow channel composed of two adjacent plates in the plate heat exchanger. Generally, several flow channels are connected in parallel or series to form different combinations of cold and hot medium channels.

The process combination form shall be determined according to the calculation of heat exchange and fluid resistance and meeting the requirements of process conditions. Try to make the convection heat transfer coefficient in the cold and hot water channels equal or close to each other, so as to obtain the heat transfer effect. Because when the convective heat transfer coefficient on both sides of the heat transfer surface is equal or close, the heat transfer coefficient obtains a larger value. Although the flow velocity between plates of plate heat exchanger is different, the average flow velocity is still used in the calculation of heat exchange and fluid resistance. Since the connecting pipes of "U" single process are fixed on the compression plate, it is convenient to disassemble and assemble.

In the design and selection of plate heat exchanger, there are certain requirements for pressure drop, so it should be checked. If the check pressure drop exceeds the allowable pressure drop, the design and type selection calculation shall be carried out again until the process requirements are met.

computing method

The calculation of heat transfer coefficient and pressure drop is obtained from the performance curves of products of various manufacturers. Performance curve (criterion correlation) generally comes from product performance test. For the plate type lacking performance test, the criterion correlation of the plate type can also be obtained according to the characteristic geometric dimensions of the plate type through the reference size method, which is adopted by some general software in the world.

Selection software

As for the selection software of plate heat exchanger, generally, each manufacturer has its own selection software according to its own plate type. HTRI and HTFs are commonly used internationally. General calculation software is rarely disclosed. Some domestic websites, such as heat exchange support website, provide online calculation software of plate heat exchanger for reference.