Performance Analysis And Optimization Of Separating Gravity Heat Pipe Based On Micro-channel Heat Exchanger

The separating gravity heat pipe is a new type of heat dissipation device.It has the advantages of flexible arrangement,high EER and stable operation because of separated arrangement of evaporator and condenser and getting power from density difference of refrigerant in upward tube and downward tube.So it is widely used in heat dissipation in data center and base station.Compared with the traditional heat exchanger,the microchannel heat exchanger has compacter structure,bigger heat transfer capacity,and lower filling rate.In recent years,the research and application based on it has been increasing,and the potential of development is great.Applying microchannel heat exchanger to separating gravity heat pipe is a great potential heat dissipation scheme.In order to research working characteristics of separating gravity heat pipe system and factors which effect on performance of the system,a steady-state numerical simulation model was built based on heat pipe system’s heat transfer performance and dynamic performance,and programming to realize the model.Then,doing experimental study of the heat pipe system on experimental table.The experimental results show that the optimum filling rate of the system is between 90%~110%,and the system performance under the higher liquid filling rate is better than the system under the lower liquid filling rate.By comparing experimental data and numerical models outputs under the optimum liquid filling rate,it is found that the relative error is 5.93% in heat transfer capacity,and 9.18% in pressure.The experimental data are basically consistent with the changing trend of the calculated results in different conditions.The result shows that the performance of the system is mainly limited by the insufficient heat transfer capacity of the system when the heat transfer condition is poor or the heat transfer temperature difference is small.When the height difference of the heat exchanger is low or the internal pressure drop of the system is large,the performance of the system is mainly limited by the insufficient power.Finally,studying on properties of heat pipe system performance in different heat exchanger height difference,heat exchanger flow distribution,flat tube parameters and fin parameters based on the output of the numerical simulation model.It provides some references for the design and application of the separation type heat pipe gravity system based on the microchannel heat exchanger.