Plate type selection
Plate type or corrugated type should be based on the actual needs of heat exchange applications. In the case of a large allowable pressure drop for the flow rate, a plate type with a small resistance should be used, and a plate type with a large resistance should be used instead.
According to fluid pressure and temperature conditions, determine whether to select gasket plate heat exchanger or brazed plate heat exchanger.
When determining the plate type, it is not advisable to select the sheet with a small area, so as to avoid excessive number of plates, small flow rate between plates, too low heat transfer coefficient, and more attention should be paid to this problem for larger heat exchangers
Process and channel selection
Process refers to a set of parallel flow channels in the same direction of flow of a medium in a plate heat exchanger, and a medium flow channel formed by two adjacent plates in a flow channel finger plate heat exchanger.
In general, several flow channels are connected in parallel or in series to form different combinations of cold and hot media channels.
The type of flow combination should be calculated based on the heat exchange and fluid resistance, and determined under the requirements of the process conditions. Try to make the convective heat transfer coefficient in the cold and hot water flow channels equal or close to each other, so as to obtain the best heat transfer effect
Because the heat transfer coefficient is equal or close to both sides of the heat transfer surface, the heat transfer coefficient obtains a larger value. Although the flow rate between the plates of the plate heat exchanger is not equal, it is still calculated at the average flow rate when calculating the heat exchange and fluid resistance.
Because the "U" shaped single process of the nozzles are fixed on the compression plate, it's easy to disassemble and install
The pressure drop check
In the design and selection of plate heat exchangers, pressure drop is generally required, so it should be checked
If the check pressure drop exceeds the allowable pressure drop, the design selection calculation shall be carried out again until the process requirements are met
The heat transfer coefficient and pressure drop are calculated by the performance curve of each manufacturer's products
The performance curve (canonical correlation) generally comes from the performance test of the product
For lack of performance testing of plate type, but also by reference dimension method, according to the characteristics of plate type geometry to obtain the rules of plate type correlations, some international common software adopts this method
As for the type selection software of plate heat exchanger, generally each manufacturer has its own type selection software according to its own plate type
International common software include HTRI, HTFS, etc. Common computer software is rarely disclosed. Some domestic websites, such as heat exchange support website, provide online calculation software of plate heat exchanger for reference