Design, Manufacture And Heat Transfer Performance Of Thermal Diode Wicks

Heat pipe is widely used in the field of heat dissipation of electronic devices as an efficient heat transfer component.With the rapid development of electronic products,the function of traditional heat pipe can not meet the heat transfer requirements of existing electronic products.The traditional heat pipe is bidirectional,that is,heat is transferred from the high end to the low end.Therefore,when the temperature of the condensing end is higher than that of the evaporation end,the heat will be transferred in the reverse direction,that is,from the original condensing end to the original evaporation section.Ultimately,external heat is transferred to the heating element(chip or CPU),causing damage to the heating element.In order to solve the above problems,this paper proposes a micro-structured liquid suction core which can control the unidirectional flow of liquid,and designs a thermal diode based on the micro-structured liquid suction core,which has the characteristics of unidirectional heat transfer.The liquid is subjected to different resistances when flowing in the positive and negative directions of the micro-structural suction core.When the thermal diode forward heat transfer,the liquid from the condensation to the evaporation section of the resistance is small,the heat pipe can realize the phase transition cycle.When the thermal diode conducts heat in reverse,the liquid flow direction changes and the resistance is large at this time,so that the liquid backflow is blocked and the evaporation section gradually becomes dry,and the phase transformation cycle inside the thermal diode is interrupted,which ultimately leads to heat transfer failure.According to the design,the thermal diode is manufactured and tested.The test results show that the maximum ratio of positive and negative thermal resistance of the thermal diode is 4 times under appropriate parameters.In this paper,a micro-structured liquid suction core controlling unidirectional liquid flow is applied to the design of heat pipe,and a thermal diode which can realize unidirectional heat transfer is proposed,which provides a new idea for the research of unidirectional heat transfer cooling element.The main research contents include:(1)A micro-structured liquid suction core which can control the unidirectional flow of liquid is proposed.Based on the micro-structured liquid suction core,a thermal diode which can realize unidirectional heat transfer in horizontal and vertical directions is designed and manufactured.(2)COMSOL Multiphysics simulation software was used to conduct numerical simulation of the micro-structured liquid suction core under different parameters,and according to the simulation results,parameters of the micro-structured liquid suction core were optimized.The micro-structured liquid core was fabricated on the surface of silicon wafer by ultraviolet laser scanning technology.(3)Make thermal diodes according to the design scheme,and build a test platform to test the performance of thermal diodes.The heat transfer performance and unidirectional heat transfer characteristics of thermal diode under different filling rate,heating power and tilt Angle were studied.