封装PCM/蜂窝陶瓷复合蓄热模型设计及数值模拟研究

The Structure Designing and Numerical Simulation Studying of the Thermal Storage Honeycomb Ceramic Encapsulated PCM

太阳能热发电技术是一种将太阳热能转化为电能的新兴发电技术,蓄热系统则是太阳能热发电技术的核心和关键,研究和开发高性能的蓄热材料意义重大。设计了一个集蓄热和高效换热一体化的封装PCM/蜂窝陶瓷复合蓄热结构模型,并对其充热和放热过程进行数值模拟。将蜂窝陶瓷一部分孔洞封装相变材料,另一部分孔洞作为换热通道,采用FLUENT软件对PCM/蜂窝陶瓷复合蓄热模型的充热和放热过程进行数值模拟研究。结果表明,封装PCM热导率越大,其充热时间越短,充热效率越高;NaCl熔盐相变潜热大,在放热过程中能够提供长时间的恒温热源,使换热介质在出口时的温度稳定,有利于太阳能热发电系统的稳定运行。

Solar thermal power generation is a new technology which can directly covert the heat energy to electricity energy. The thermal storage system is the core component in solar thermal power stations.Researches and developments of thermal storage materials with high-performance are significant. A thermal storage structure model using honeycomb ceramic encapsulated PCM was designed on the bases of the acting mechanism between PCM and ceramics in this research. Parts of honeycomb ceramic holes encapsulated PCM, and the other parts were used as heat exchange channels. Heat storage/exothermic process of the thermal storage model were in numerical simulation studied by using FLUENT software. The results indicated that the higher the PCM thermal conductivity, the greater the heat storage efficiency is, and the less time it takes for heat storage. It is believed that the honeycomb ceramics encapsulated NaCl could provide a constant temperature heat source and keep the exit temperature steady due to the huge latent heat of phase change of NaCl. This is good for the stable operation of solar thermal power generation.