Heat Transfer Devices With Self-Rewetting Fluids

Abstract

The authors have been proposing the utilization of “self-rewetting fluids” as a new phase change heat transfer media, especially in space applications. Self-rewetting fluids show a quite unique thermophysical behavior—an increase in the surface tension with increasing temperature. Since self-rewetting fluids are non-azeotropic compositions of dilute aqueous solutions of alcohols, the Marangoni effects due to both temperature gradient and concentration gradient work in the same direction in the course of liquid/vapor phase change, and induce a strong liquid flow to hotter interface. A series of terrestrial experiments for conventional heat pipes with self-rewetting fluids have been conducted, and compared with those with water as a reference. Appreciable heat transfer performance improvement from water heat pipes was recognized. Furthermore, a series of low gravity experiments for wickless heat pipes with a self-rewetting fluid have also been conducted by using parabolic flights of aircraft. The heat transfer performance of wickless heat pipes in low gravity was evaluated, and superior characteristics was confirmed.