| Nowadays,with the miniaturization of the internal space of electronic products,the high heat flux density problems caused by the high integration,high power consumption and small size of various IC chips are also becoming increasingly prominent.Therefore,how to efficiently realize the rapid heat dissipation of electronic components with small space and precise temperature control has become the key to restrict the development of the electronic industry,which is the research significance of this paper.In this paper,seven kinds of flat micro-heat pipes with different channel sections are selected as the research object.Firstly,three kinds of shallow rectangular micro-grooves of different structure sizes are processed according to the design drawings,and then further processed into deep rectangle,shallow V-shaped and deep V-shaped.And ? shape four different channels.Then,the three kinds of working fluids of water,ethanol and acetone were used to test the capillary force of the micro-groove by dynamic height method,and the results were compared with the theoretical values for verification and analysis,so as to characterize the performance of the influence of different channel structures and working mediums on the capillary force.The laboratory designed and built a platform to test the heat transfer performance of flat micro-heat pipe under different working conditions.By analyzing some main factors affecting the related performance of the flat micro-heat pipe,a series of evaluation parameters representing its start-up,temperature uniformity and heat transfer performance were selected for the research and analysis.The start-up and temperature uniformity of the encapsulated flat heat pipes with four micro-grooves were tested,and the effects of several different factors on the heat transfer performance of the heat pipes were further studied.In addition,the surface optimization treatment was carried out on the flat micro-heat pipe with the best heat transfer performance among the test results,and the influence of surface performance change on the capillary force of the micro-channel channel and its improvement on the heat transfer performance of the micro-heat pipe were explored.The experimental results of the capillary force test using the dynamic height method show that the capillary phenomenon is the most obvious when using the acetone working medium,followed by ethanol,and the worst effect when using the hydraulic working medium.The capillary forces of three different shallow rectangular channels are: 3#shallow rectangle>1#shallow rectangle>2#shallow rectangle;The result of comparing the capillary force of the 3# shallow rectangle with several other different microgroove channels is: deep V shape> shallow V shape> deep rectangle> Omega shape > shallow rectangle.The heat transfer performance test of the four micro-slot flat heat pipes after packaging is as follows:deep rectangle > ? shape > shallow rectangle > V shape.The results show that the rectangular micro grooves flat heat pipe heat transfer performance of the best;the ?-shaped micro-groove because of its special structure of the opening size is smaller than the hydraulic diameter of the main channel and has no sharp corner area,which can greatly reduce the shear friction between the steam and the reflux condensate,so that the required capillary driving force is reduced,so the heat transfer performance Second only to the deep rectangular flat micro heat pipe;while the V-shaped channel has a large capillary force,but the angular area is only half of the rectangular channel,so the heat transfer performance is the worst;in the deep rectangular micro heat pipe with better heat transfer performance After the surface modification of the channel,the capillary force is increased by 10.4% compared with that before the modification,and the heat transfer performance is also obviously enhanced.In addition,the flat micro heat pipes designed in this paper have good starting performance and isothermal performance. |
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