太阳能热气流发电系统非稳态耦合数值分析

UNSTEADY NUMERICAL CONJUGATE SIMULATION OF THE SOLAR CHIMNEY POWER GENERATION SYSTEMS

对包含蓄热层的太阳能热气流发电系统的传热与流动特性进行非稳态耦合数值模拟。建立了集热棚、烟囱以及蓄热层内部传热与流动数学模型。分析了不同蓄热介质的太阳辐射响应特性对系统昼夜发电峰谷差的影响,计算结果表明:采用热容较高的土壤作为蓄热介质可以有效降低昼夜平均温度的峰谷差,从而有效调整系统的昼夜发电峰谷差;蓄热层表面温度越高,系统不可逆性越大,能量损失和可用能损失越大;蓄热层导热系数越大,蓄热层表面温度越小,烟囱出口平均温度和平均速度越高,通过烟囱出口的能量损失越大。

Unsteady conjugate numerical simulations have been performed to analyze the characteristics of heat transfer and air flow in the solar chimney power plant system with energy storage layer. Different mathematical models for the collector, the chimney and the energy storage layer have been established, and the effects of solar radiation on the heat storage characteristic of the energy storage layer have been analyzed. The numerical simulation results show that It is beneficial for the utilization of soill, with comparatively higher heat capacity, as the material of energy storage layer, which could effectively modulate the temperature and power output difference of the solar chimney power plant systems between the daytime and night, and that the higher the temperature of the surface of the storage medium, the larger the energy loss and the exergy loss from the solar chimney power plant systems. In addition, the larger the conductivity of the energy storage layer, the lower the surface temperature of the energy storage layer, but the higher the temperature and the velocity of the chimney outlet which means a larger energy loss from the chimney outlet.