Fabrication And Heat Transfer Performance Of Ultra-thin Aluminum Flat Heat Pipes Based On Porous Wick

In recent years,the thermal management requirement of electronic equipment has been increasingly improved,and the phase change heat pipe has been widely used because of its excellent heat transfer efficiency.Amon the phase change heat pipe,aluminum plate heat pipe has the advantage of larger heat transfer area,lower cost,better adaptability in large heat source area situation.However,the traditional aluminum plate heat pipe usually has larger thickness with the wick structure of extruding micro grooves,which has poor capillary performance.Therefore,based on the continuous extrusion technique and phase change flattening process,this paper developed a new manufacturing method of ultra-thin aluminum plate heat pipe with porous wicks--secondary molding methods.With this method,the ultra-thin aluminum plate heat pipes based on porous wicks were fabricated,with the thickness of only 1.5 mm.Therefore the capillary limit of the aluminum plate heat pipe was improved significantly.The experimental results indicated that the heat transfer performance and the ultimate heat transfer power of the ultra-thin aluminum plate heat pipe was improved effectively.The highlights of this paper are as follows:(1)The forming mechanism of the porous wicks structure of the ultra-thin aluminum plate heat pipe was explore.Using aluminum fiber from cutting process to fabricate the sintering aluminum fiber porous structure,and preparing aluminum fiber bundle woven mesh porous structure with knitting machine weaving and surface corrosion method.Besides,angle method and high speed camera were used to analyze the wettability of the porous wicks,and through IR-thermal imaging method to study the capillary rise height and rise rate of the porous wicks.Then the integrated capillary performance of various porous wick structures was analyzed.(2)Flattening test was carried out to study the structure of the continuous-extrusion pre-forming structure and the introduction position of the porous wicks.Then the manufacturing process of the porous wick ultra-thin aluminum plate heat pipe was studied based on the manufacturing process of the traditional aluminum plate heat pipe.At the same time,the corresponding heat transfer performance test platform was designed to study the response performance and steady-state performance of the ultra-thin aluminum plate heat pipe.(3)By comparing the porous wicks ultra-thin aluminum flat heat pipe with the traditional smooth wall aluminium plate heat pipe,its competitive heat transfer performance obtaining from the porous wick structures was justified.Besides,the antigravity heat transfer performance of the porous wicks ultra-thin aluminum plate heat pipe was investigated.And the effect of the porous wick structure,heat transfer angle and cooling velocity on the heat transfer performance of the ultra-thin aluminum plate heat pipe was studied as well so as to analyze the influence mechanism of the structure and working conditions on the heat transfer performance of the ultra-thin aluminum plate heat pipe.