TY - JOUR TI - Influence of void ratio on phase change of thermal energy storage for heat pipe receiver AU - Xiaohong Gui AU - Tie Li AU - Shiqiang Liang AU - Dazhong Yuan AU - Dawei Tang JN - Thermal Science PY - 2015 VL - 19 IS - 3 SP - 967 EP - 976 PT - Article AB - In this paper, influence of void ratio on phase change of thermal storage unit for heat pipe receiver under microgravity is numerically simulated. Accordingly, mathematical model is set up. A solidification-melting model upon the enthalpy-porosity method is specially provided to deal with phase changes. The liquid fraction distribution of thermal storage unit of heat pipe receiver is shown. The fluctuation of melting ratio in PCM canister is indicated. Numerical results are compared with experimental ones in Japan. The results show that void cavity prevents the process of phase change greatly. PCM melts slowly during sunlight periods and freezes slowly during eclipse periods as void ratio increases. The utility ratio of PCM during both sunlight periods and eclipse periods decreases obviously with the improvement of void ratio. The thermal resistance of void cavity is much higher than that of PCM canister wall. Void cavity prevents the heat transfer between PCM zone and canister wall.