Design And Performance Research Of Integrated Indirect Liquid Cooling System For Rack Server

The development of new technologies such as internet of things,blockchain and artificial intelligence puts forward higher requirements for the computing performance of servers in edge data centers,and the heat dissipation of servers is the key factor restricting their performance improvement.Therefore,this paper proposes an integrated indirect liquid cooling system for the server of the edge data center to improve the heat dissipation performance and the flexibility of edge computing force deployment.The heat transfer performance and flow characteristics were investigated through experiments and numerical simulation.The main contents of the paper are as follows:(1)According to the guidance of thermal design,structural design and component selection,two sets of integrated indirect liquid cooling system prototypes installed inside and outside the server were manufactured,and the processing and welding process of cold plate components were described in detail,including the manufacturing process of heat sink,heat pipe and cold plate.The main factors affecting the heat dissipation performance of cold plate components were analyzed,and the evaluation index of heat transfer and flow characteristics of integrated indirect liquid cooling system were determined.(2)The performance test platform of integrated indirect liquid cooling system was built,and the heat dissipation performance under different flow rate,power and water temperature was investigated through experiments.The experimental results show that there is a linear correlation between the chip power and its surface temperature.Compared with air cooling,the maximum chip temperature under liquid cooling is about 23℃.Increasing the flow rate can improve the heat dissipation performance,and the surface temperature and heat transfer resistance of the chip are reduced.However,further increasing the flow rate leads to the reduction of heat dissipation efficiency,and the change trend of the performance parameters slows down.When the power is 40 W and 55 W,the heat dissipation will not change.Increasing the power has the effect of expanding the heat dissipation range of cooling water.And the flow required for heat dissipation increases with the increase of power.The increase of water temperature also improves the heat dissipation range of cooling water.When the water temperature increases,increasing the flow rate is more conducive to heat dissipation.However,the surface temperature of the chip,the total thermal resistance of the system and the temperature difference of the cold plate all increase,indicating that the increase of water temperature reduces the heat dissipation performance.The pressure drop analysis shows that the flow characteristics of the two integrated indirect liquid cooling systems installed inside and outside are similar,and the pressure drop loss increases with the increase of flow rate.However,there is a large gap between the two,in which the feasibility of the external system is better.At the same time,it is found that the system feasibility is promoted when the water temperature rises,and the internal system shows certain feasibility under some flow rates.(3)The numerical simulation model was established.The temperature control performance of air cooling and liquid cooling server was compared and analyzed,and the effectiveness and reliability of the numerical simulation model were verified by experiments.The numerical simulation results show that the temperature control effect of the server with the external integrated indirect liquid cooling system is better.Finally,when the liquid cooling server was applied to the edge computing integrated cabinet,the overall heat dissipation performance was numerically simulated and analyzed.When the temperature is 24 ℃,the overall temperature control effect of the server in the single cabinet is the best.