Requirements to be met before the selection of plate type heat exchangers
The two mediums of the plate heat exchanger perform hot and cold heat exchange. In the working condition where the two media do not change phase, before the selection calculation, it is generally required to meet certain requirements in order to operate normally:
(1) The convective heat transfer coefficient of the two media in the plate heat exchanger and its total heat transfer coefficient along the heat exchange surface can be regarded as constant.
(2) The heat loss occurring during the heat exchange process is negligible, because the heat loss is unavoidable during the heat exchange process, and the heat lost during the normal heat exchange process is extremely small and can be ignored.
(3) When the flow rate in the fluid passage is evenly distributed, the axial pressure gradient in the angle box is determined to be 0.
(4) For the change that occurs under multi-process conditions, the resulting additional pressure drop is negligible.
(5) The partial pressure drop from the inlet of the plate heat exchanger and from the passage of the plate heat exchanger plate shall be included in the pressure drop along the path.