Experimental and Theoretical Analysis on Enhanced Flat Miniature Heat Pipes with Axial Capillary Grooves and Screen Meshes

Combined experimental and analytical studies are realized in order to verify the flat mini heat pipe (FMHP) concept for cooling high power dissipation electronic components, and determine the potential advantages of constructing arrays of mini channels as an integrated part of a heat pipe. A mixed capillary system, which is composed of screen meshes and mini-channels, is used in order to manufacture the FMHP. In the experimental study, different FMHP prototypes are manufactured and tested. The number of screen meshes is kept the same for the different tested configurations; however different meshing sizes are used. The heat transfer improvement, obtained by comparing the heat pipe thermal resistance to the heat conduction thermal resistance of a copper plate having the same dimensions as the tested heat pipes, is demonstrated for the different prototypes. The heat transfer enhancement depends on the input heat flux rate, the screen mesh porosity, and the FMHP orientation in respect to gravity. In the analytical study, a model of MHP with mixed capillary structure is developed. The comparison between the analytical and experimental results shows a good agreement in predicting both the maximum capillary limit and the FMHP thermal resistance