Etude expérimentale, hydrodynamique et thermique de l’évaporation dans les structures capillaires de caloduc

Abstract

The progress in the electronics has permitted the development of different height power components in a very small time. Consequently, as the number of elements, the dissipative power per surface unit has augmented. The high temperatures produce a smaller period of life, so it’s necessary to develop more efficient refrigeration methods. The CETHIL (thermal center of Lyon) studies cooling systems of low thickness systems, the flat heat pipes. They use the changing phase liquid-vapor as a method to transfer heat between a warm source and a cold one. These systems are particularity efficient, because they enable to transfer a high density of heat fluxes. During a previous project, a flat heat pipe with bronze metallic drills and methanol as the intern fluid was tested. The results obtained were promising even if the heat pipe did not work in an unfavorable position. The objective of this new project is to test the same flat heat pipe with a new fluid, water, and the same metallic drills, but oxidized to improve the wettability with water. The optimal operating parameters of these systems are presented as the capability to transferred power according to the orientation or the debit fluid influence. The results are compared with the operating conditions of the heat pipe in previous studies and also with the calculated values from the expressions of bibliography studies. The results show good performances of the studied heat pipe, even when this one is in an unfavorable vertical position Key words: Heat spreader, flat heat pipe, two-phase heat transfer, metallic mesh, electronic cooling, and experimental study.