Research On The Manufacture Of Flat Heat Pipe And Its Heat Transfer Performance

Since entering the new century,with the rapid development and application of electronic information technology,the development of electronic components shows a trend of high speed,high frequency and high integration.The flat heat pipe has many advantages,such as ideal uniform temperature,high thermal conductivity and compact structure,so it has become a reliable solution to the problem of electronic heat dissipation.However,most of the traditional flat heat pipes can not bend or work normally after bending.At present,the heat transfer coefficient of organic polymer flat heat pipe is low.Accordingly,a new type of flat heat pipe made of metal aluminum and foam aluminum as the wick is manufactured in this paper.The flat heat pipe has the advantages of low cost,light weight,good ductility and flexibility.It can improve the space utilization of electronic equipment and meet the heat dissipation requirements of curved surface electronic equipment,thus expanding the application scope of the heat pipe and providing new ideas for solving the current non-planar heat dissipation problems.This study includes three aspects:Firstly,the basic theory of heat pipe and the heat transfer limit affecting the heat transfer capacity of flat heat pipe are discussed,the flow characteristics of liquid and steam in the tube are discussed,and the working fluid charge of flat heat pipe is discussed.The thermal resistance network diagram of flat heat pipe is analyzed,and the thermal resistance of each heat transfer process is analyzed;Secondly,through the analysis of the traditional flat heat pipe processing technology,it is proposed that the flat heat pipe should be manufactured by the process of first flattening and filling and sealing.According to the characteristics of the metal,the aluminum with low cost,good ductility and light weight will be selected as the flat heat pipe material.The collapse phenomenon of the aluminum tube in the process of pressing will be discussed,and the foam aluminum wick can be placed in the middle of the tube.The flat heat pipe was successfully manufactured by cleaning,flattening,filling,sealing and other processes.Thirdly,the working temperature of flat heat pipe under different conditions,such as power of heat source,filling rate and bending angle,is measured by setting up an experimental platform,and its heat transfer performance is evaluated comprehensively by temperature difference(35)T and thermal resistance R.It is verified that the flat heat pipe can work normally at the horizontal level,and the heat transfer performance is the best when the power is 25W~28W.The flat heat pipe also has good heat transfer performance when bending,and its heat transfer performance increases with the increase of bending angle.