Combined effects of the filling ratio and the vapour space thickness on the performance of a flat plate heat pipe

Abstract An experimental study of a flat plate heat pipe (FPHP) is presented. Temperature fields in the FPHP are measured for different filling ratios, heat fluxes and vapour space thicknesses. The system is hermetically sealed with a transparent plate for meniscus curvature radius observations by confocal microscopy. Experimental results show that the liquid distribution in the FPHP – and thus its thermal performance – depends strongly on both the filling ratio and the vapour space thickness. A small vapour space thickness induces liquid retention and thus reduces the thermal resistance of the system. Nevertheless, the vapour space thickness influences the level of the meniscus curvature radii in the grooves and hence reduces the maximum capillary pressure. As a result, it has to be carefully optimised to improve the performance of the FPHP. In all the cases, the optimum filling is in the range one to two times the total volume of the grooves. A theoretical approach, in non-working conditions, has been developed to model the distribution of the liquid inside the FPHP in function of the filling ratio and the vapour space thickness.

[1]  Amir Faghri,et al.  A three-dimensional thermal-fluid analysis of flat heat pipes , 2008 .

[2]  F. Lefèvre,et al.  Confocal Microscopy for Capillary Film Measurements in a Flat Plate Heat Pipe , 2010 .

[3]  Frédéric Lefèvre,et al.  Coupled thermal and hydrodynamic models of flat micro heat pipes for the cooling of multiple electronic components , 2006 .

[4]  S. Kim,et al.  Analytical and experimental investigation on the operational characteristics and the thermal optimization of a miniature heat pipe with a grooved wick structure , 2003 .

[5]  L. L. Vasiliev,et al.  Micro and miniature heat pipes – Electronic component coolers , 2008 .

[6]  G. Pandraud,et al.  Prediction of the temperature field in flat plate heat pipes with micro-grooves – Experimental validation , 2008 .

[7]  M. Lallemand,et al.  Effect of interfacial phenomena on evaporative heat transfer in micro heat pipes 1 Based on a paper , 2000 .

[8]  Amir Faghri,et al.  Flat Miniature Heat Pipes With Micro Capillary Grooves , 1999 .

[9]  J. E. Beam,et al.  Experiments and Analyses of Flat Miniature Heat Pipes , 1997 .

[10]  D. Khrustalev,et al.  Coupled Liquid and Vapor Flow in Miniature Passages With Micro Grooves , 1999 .

[11]  Jon P. Longtin,et al.  A One-Dimensional Model of a Micro Heat Pipe During Steady-State Operation , 1994 .

[12]  Marcia B. H. Mantelli,et al.  Investigation of a wire plate micro heat pipe array , 2004 .

[13]  Frédéric Lefèvre,et al.  Prediction of the maximum heat transfer capability of two-phase heat spreaders – Experimental validation , 2007 .

[14]  Stéphane Lips,et al.  Nucleate boiling in a flat grooved heat pipe , 2009 .

[15]  Amir Faghri,et al.  Heat Pipe Science And Technology , 1995 .