Study On Heat Transfer Performance Of Cylindrical Thermal Storage Unit In Vertical In Moderate And High Temperature In Solar Thermal Utilization

Solar energy is a rich in resource, clean, non-polluting, renewable energy, and therefore attract the attention of many countrys in the world. Since the Eleventh Five-Year, the independent development of condenser solar thermal power technology has been strong supported by China’s Ministry of Science and Technology, but compared to the country abroad, this technology in our country is still in its infancy. Solar thermal power generation has broad prospects for development, but the intensity of solar radiation is instability and intermittent, to compensate for this deficiency, energy storage is a key ring to solve the problem, so that eventually become a convenient and reliable clean energy from the auxiliary energy. The study of phase change energy storage in solar thermal power generation, at home and abroad, still in the laboratory stage.Al-Si alloys compared with other metals phase change thermal storage materials, the phase transition temperature is moderate, the latent heat is large, heat transfer performance is good, the undercooling is small, and is rich in resources and high cost performance characteristics. The research of Al-Si alloy is mainly concentrated in the thermal properties, container compatibility, but little in the research of Al-Si alloy and its heat storage body in the solar high-temperature heat thermal storage system, in the charging and discharging process.This paper for the purpose of the application of Al-Si alloy energy storage material in the tower solar thermal power system, researched the heat transfer performance of the cylindrical thermal storage unit in Vertical with PCM. Through numerical simulation and experimental research methods to study the heat transfer process of law of thermal storage process in charging and discharging process. A model of cylindrical thermal storage unit in vertical was established and simulated using FLUENT6.3, which was heated by the out half circumference in the charging process and cooled by the central tube in the discharging process.3cylinder structures were chosen to simulate, each of them was heated on the half circumference and cooled by the central tube under heat flux of100and200kW/m2, and heated on all circumference under heat flux of50and100kW/m2. The movement of phase change interface and the temperature change of Al-Si alloy were analyzed with the temperature contour. The simulation results show that the temperature of Al-Si alloy is stable around850K in the most time of whole process, and the highest temperature is no more than920K during heat charging process, while the lowest temperature is above500K in heat discharging process. Get the law of heat transfer process, by analyzing the temperature variation of the heat storage body, and melting area variation. Through the heating experiments, get the temperature change law of the Al-Si alloy in the actual heating process, and compared with the simulation results. Through heat transfer experiments in tube, obtained heat transfer rules, ranged the experiment temperature, and fitted the heat transfer criterion correlation.