Improvement measures for heat transfer effect of plate heat exchanger

In order to ensure continuous use period, the heating quality can still meet the design requirements, in addition to control water indicators (such as suspended solids content, hardness, and chloride ion content etc.), to strengthen the operation of pH management, we should improve the plate structure of heat exchanger.

In recent years, based on the circulation section of BR type is developed from the circulation section BB plate type heat exchanger, calculation and comparison of table BB0.5 and BR0.5 1 in the results: heating quality index and thermal performance of the type 0.5 BB were better than BR0.5. But even so, the BB type can not guarantee the necessary heating quality after considering the dirt thickness. In this paper, it is suggested that the installation distance between plate and plate should be reduced to improve the heating quality. In my opinion, it is necessary to increase the plate height to width ratio of the plate heat exchanger, and improve the heating quality of the plate heat exchanger to a certain extent.

Take BB0.3 as an example. Set the plate width, corrugated shape, plate spacing is also unchanged, only change the plate height, the heat transfer area of monolithic increased from 0.3m2 to 0.5m2, and that the plate type BB0.3 - A. Because the qualitative dimension of the Nusselt equation is the plate spacing, the BB0.3 - A and BB0.3 - type can adopt the same equation. Of course, the experimental coefficients in the Nusselt equation change with the height of the plate. In this paper, the BB0.3 - A model is calculated under the condition that the total thickness of sediment is 0 and 0.2mm, and the area coefficient CF is taken as a factor of 0 and 0.15. The results are shown in table 3.

                                                             
     As calculated in the selection of plate heat exchanger, the theory of heat transfer area F0 a side heat medium flow rate is 0.4m / s to determine what, if the selected area is not considered additional, is continuously used in plate heat exchanger the pre heating quality can meet the design requirements, and the latter is still not up to two times the water temperature the provisions of the. However, if the heat exchange area increased by 15%, even in the plate heat exchanger, the use of the latter, the design requirements of the heating quality can still be guaranteed.