| Urban domestic sewage is an excellent green renewable energy. Improving the utilization level and exploring the energy potential of waste water has important practical significance for the construction of a resource-saving and environmentfriendly society. Sewage-source heat pumps technology is a key pathway for achieving wastewater heat recovery efficiently, however, the whole performance of heat pump system limited to the performance of the heat exchanger. There exists some problems of conventional heat exchanger in coping with the problems of blockage,corrosion, low efficiency in the sewage-side heat exchanger caused by the water quality. Heat pipe is a highly efficient heat exchanger components, and it’s quite a meaningful attempt to promote the application of heat pipe in the wastewater source heat pump systems to effectively address these problems above. This paper has explored the influence on flow and heat transfer performance caused by baffle structure of heat exchanger from the perspective of research and development efficiency water heat exchanger, also the feasibility of baffle structure on strengthening phase change heat exchanger performance was cleared.This article started by water heat exchanger designing, and it also analyzed the theoretical basis of and possible avenues of heat pipe heat exchanger utilization in sewage heat application. This paper proposed the possibility of introducing a baffle structure in tubes heat exchanger to enhancing heat transfer performance accord to the possible ways to reduce the thermal resistance of the control, combined with the mature design methods of shell and tube heat exchanger in Engineering Practice. Theoretical part of the article contains the following, ① Heat transfer mechanism of two-phase closed thermosyphon and Conception in sewage heat recovery.② Analyzed the heat transfer process, compared to the various parts of thermal resistance, proposing possible ways of heat transfer enhancement.③ Optimized the design of heat exchangers of experimental group and control, determined the structural parameters of the various parts of the heat exchanger.④ Analyzed the flow and heat performance of heat exchanger, determined the pathway of flow and heat,established theoretical foundation for subsequent experiments and data analysis.It designed control group(without baffle flow- heat transfer test) compared with experimental group(with baffle flow- heat transfer test) in the testing stage to evaluate the influence to performance caused by different heat transfer structure and fluid inlet way.This paper found the optimum heat exchanger performance conditions by analyzing the data of experimental group and the control.Also the flow- heat transfer performance of the evaporator, condenser section of the exchanger was tested under the condition of variable flow.The experimental data and the theoretical calculations was compared and experiment error was analyzed after this experiment.Following conclusions drawn in this paper compared the experimental data and the control.1) Way fluid inlet has an effect on the performance of heat exchanger in control group. The optimal performance of control group appears in the working condition of the sewage and the water flows from the upper part of heat exchanger. 2) Flow rate in the condensation section is influential to the performance of the heat exchanger in the experimental group. Heat transfer and heat transfer coefficient with the sewage flow rate increases.The ratio of evaporation section length and condensation section length has quite an effect on the performance of heat exchanger.The overall heat transfer coefficient increased by 35% and 56% respectively as the ratio of 1 2l/ l changes from 480/220 to1 and 220/480.3) Performance improved significantly after the installation of baffles. 4)The optimal performance of experimental group with variable flow operation in evaporation and condensation appears in minimum water flow. The value of 1f and hE equals to 2.19 and 415.39 respectively at this moment. |
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