Visualization And Heat Transfer Experiment Of Silicon-Based Micro Loop Heat Pipe

With the development of information technology,electronic components have evolved toward high frequency,high speed,and miniaturization and integration of integrated circuits,and the heat flux density of electronic components has also risen sharply.Studies have shown that excessive temperature can seriously affect the performance of electronic equipment,which can easily cause serious system failure or even burn down the equipment.When the junction temperature of the power transistor is greater than 70℃,the reliability is reduced by 5 0%for every 10 degrees increase in temperature.How to achieve high heat flux density in a limited temperature range and a small space has become a bottleneck restricting the development of high technology.The heat pipe is an efficient passive heat sink.In recent years,the development and research of new high-efficiency micro-heat pipes have received extensive attention.With the rapid development of semiconductor processing technology,the integration of electronic components and thermal control components is favored.The silicon-based micro-loop heat pipe can be directly integrated with electronic components,greatly reduce the volume and the heat transfer resistance,and the loop heat pipe is based on phase transforming the thermal mechanism and having obvious advantages of efficient heat dissipation.In recent years,the development and research of new high-efficiency ultra-thin heat pipes have received extensive attention.In fact,the further breakthrough in the development of ultra-thin heat pipes is to make better use of micro/nano scales.Two-phase flow and heat transfer processes,especially the complex boiling phenomena in the evaporator.Therefore,for the traditional loop heat pipe heat transfer efficiency is not high enough,the volume cannot adapt to small electronic equipment,heat transfer is not stable enough,etc.This thesis designed and processed a high aspect ratio micro channel array capillary core silicon-based micro loop heat pipe(μLHP)A vacuum infusion test bench and a visual mass transfer heat transfer test bench were built.The popularization characteristics and distribution of two-phase flow in μLHP were studied by visual experiments.The activation and failure characteristics of μLHP were studied,and the understanding of the flow inside μLHP was enriched.Finally,by doing experiments of the characters of the working fluid,different heat power and perfusion methods,the influent of these factor to the μLHP was researched.This thesis completed the design and the processing of the micro-loop heat pipe,the development of the pumping and heat transfer test bench,and experiment and analysis of the visual mass transfer and heat transfer.The specific work is as follows:(1)The design of silicon-based miniature loop heat pipe with high aspect ratio microchannel array capillary core was completed.The silicon base plate and glass cover plate were processed by ion etching technology and lithography technology respectively,and the silicon base ring was realized.The processing and preparation of the road heat pipe(length 80mm,width 20mm,thickness 1.5mm)provides a feasible process route for the processing of silicon-based micro loop heat pipes.(2)The silicon-based miniature loop heat pipe vacuum infusion test bench was independently developed,and the vacuum infusion of the silicon-based micro loop heat pipe was completed,which provided a new method for the silicon-based micro loop heat pipe’s vacuum pumping and control process.(3)It designs and builds a visual mass transfer heat transfer test bench to test the heat transfer performance of the silicon-based micro loop heat pipe,including the starting characteristics of the micro loop heat pipe,the minimum starting power,the failure characteristics and the heat transfer limit.Through the visualization experiment of the silicon-based micro-loop heat pipe,the flow of the internal working fluid of the silicon-based micro-loop heat pipe and the evaporation and condensation were studied,and the internal working fluid distribution and motion during the startup,smooth operation and failure were obtained.The operation law of the silicon-based micro loop heat pipe under the design is summarized.The research on the silicon-based micro-loop heat pipe shows that the siliconbased micro-loop heat pipe heat pipe can minimize the temperature of the chip and increase the overall temperature uniformity.And it has a significant advantage in the high-intensity heat dissipation and temperature control of the small components.The in-depth study of silicon-based micro-loop heat pipes is of great significance for further exploiting the advantages of this technology and meeting the heat dissipation requirements of microelectronics.