超重条件下泡沫石墨-石蜡相变传热实验研究

The phase change regenerator based on the high thermal conductivity porous material framework to enhance heat transfer has the advantages of large heat capacity, high heat exchange efficiency, stable temperature control, and strong environmental adaptability. It has a wide range of application prospects in the aerospace field. During the solid-liquid melting process in the porous media, the buoyancy variation derived from the density difference of the liquid phase driven by the acceleration would induce more complex flow and heat transfer instability during the solid-liquid phase change. In this study, an apparatus for studying solid-liquid phase change of the paraffin composited in porous media was set up, and the heat transfer characteristics of paraffin melting in porous graphite under different accelerations were obtained. The results showed that, the temperature of the thermal load can be better controlled by the phase change heat transfer of paraffin composited with porous graphite, and the general heat transfer efficiency and the nonhomogeneous thermal diffusion of the phase change energy storage device were remarkably affected by the accelerating direction. When the direction of acceleration is opposite or perpendicular to the direction of heat flow, the local natural convection of liquid phase driven by acceleration will promote the overall heat transfer efficiency of the phase change energy storage module, while the overall heat transfer efficiency will be suppressed when the direction of acceleration is in the same direction as the direction of heat flow. Besides, the temperature difference under different accelerating direction was enlarged with the increase of the acceleration.