流化床太阳能粒子吸热器内流动传热数值模拟

Numerical simulation of flow and heat transfer in a fluidized bed solar particle absorber

基于计算颗粒流体力学(CPFD)方法对内循环流化床固体颗粒太阳能吸热器中的气固两相流动进行建模,结合P1辐射模型,对吸热器内颗粒流动和传热过程进行了研究,并通过试验数据对模型进行了验证。模拟研究了吸热器在内部强制再循环作用下的颗粒流动和传热过程,分析了气体质量流量、颗粒浓度、再循环率等参数对吸热器内颗粒流动传热的影响。结果表明,气体质量流量的增加会使轴向的颗粒温度增加;随着颗粒体积分数的增大,吸热器出口气体温度和热效率均增大,但是当颗粒体积分数超过0.06%时,颗粒体积分数的增大会导致吸热器的净吸收能力和出口气体温度降低;再循环速率增大,出口气体温度和热效率呈现先增大后减小的趋势,表明需要选择合适的再循环速率以保证吸热器的良好性能。

Based on the CPFD method,the gas-solid two-phase flow in the internal circulating fluidized bed solid particle solar absorber is modeled.Combined with the P1 radiation model,the particle flow and heat transfer process in the absorber are studied,and the model is verified by experimental data.The particle flow and heat transfer process under forced internal recirculation of heat absorber is simulated,and the effects of gas mass flow rate,particle concentration and recirculation rate on particle flow and heat transfer in heat absorber are analyzed.The results show that the axial particle temperature increases with the increase of gas mass flow rate.With the increase of particle volume fraction,the outlet gas temperature and thermal efficiency increase,but when the particle volume fraction exceeds 0.06%,the increase of particle volume fraction leads to the decrease of net absorption capacity and outlet gas temperature of the absorber.With the increase of recirculation rate,the outlet gas temperature and thermal efficiency show a trend of first increasing and then decreasing,which indicates that it is necessary to chose an appropriate recirculation rate to ensure the good performance of the heat absorber.