Flow refers to a set of parallel flow channels in the same direction of flow of a medium in a plate heat exchanger, and the flow channel refers to a medium flow channel formed by two adjacent plates in a 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 convection heat transfer coefficient in the cold and hot water flow channels equal or close to each other, so as to obtain a good 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, the average flow rate is still used to calculate the heat exchange and fluid resistance. Because the "U" single-flow nozzles are fixed on the pressure plate, it is easy to disassemble and install.
The exergy analysis method was used to analyze the thermodynamic properties of the high and low temperature heat exchangers. The influence of parameters such as the number of heat transfer units of the heat exchanger and the heat capacity ratio of the hot and cold fluid on the exergy efficiency was discussed, and some useful conclusions were obtained. However, it should be pointed out that none of the existing studies systematically considers the effect of the inlet temperature of the hot and cold fluids on the thermodynamic properties of the heat exchanger, and there are few studies on the cryogenic heat exchanger. Although the heat and cold fluid inlet temperatures of many heat exchangers in engineering are given in a certain process, and cannot be optimized as the heat capacity of hot and cold fluids is less than that of R and the number of heat transfer units Ntu, it is still needed. The energy analysis and evaluation of the existing heat exchanger under the current operating parameters, including considering the influence of the inlet temperature of the hot and cold fluid, thus discovering the irreversible loss of the existing heat exchanger.
The heat exchanger is also one of the more common equipments in the industrial production process. It has important applications in many fields, but once the equipment fails, it will have a great impact. Therefore, in the normal use of the heat exchanger, it is necessary to perform regular maintenance. We also found that the problem of endoleaks in heat exchangers is often encountered. What are the necessary emergency measures?
Internal leakage occurs in the heat exchanger, possibly because the internal sealing device has failed. In this case, it is mainly necessary to replace the new gasket. Another possibility is that the tube bundle leaks. Due to the effect of various media, it may cause the heat exchanger to erode, and thus cause the tube bundle to leak. In the event of such a situation, it is also necessary to replace the tube bundle and ensure its sealing effect.
Because the heat exchanger internal leakage will affect the heat transfer effect, it may also cause damage to the equipment itself, so we must always pay attention to the occurrence of similar problems, and to promptly eliminate the fault.
