为了解决碟式太阳能斯特林发电系统的储能问题，建立1 kW β型碟式斯特林发动机储能的地上混凝土储热单元，采用计算流体力学方法，针对熔融盐流速v、储热时间t、换热管管径D、熔融盐初始温度T对混凝土桩蓄热量Q和对流换热系数h的影响进行双因素分析。结果表明：v与Q呈线性关系，但v的增大导致接触时间减少而不能充分换热，最佳流速为3 m/s；D越大达到相同Q所需时间就越短，但大管径会导致混凝土体积降低、蓄热量减少，管径为25 mm最佳；随着v的增加达到相同h所需温度越低；h随D的增大而减小，D越大达到相同h所需温度越高。通过优化管型，采用S型换热管，使得对流换热系数、蓄热量、蓄热效率都较直型换热管有所提高

In order to solve the energy storage problem of dish solar Stirling power generation system, the ground concrete heat storage unit of 1 kW βtype dish Stirling engine was established, and the computational fluid dynamics method was adopted to carry out the twofactor analysis of the influence of molten salt flow rate v, heat storage time t, heat exchange tube diameter D and initial molten salt temperature T on concrete pile heat storage Q and convective heat transfer coefficient h. The results show that there is a linear relationship between v and Q, but with the increase of v, the contact time decreases and the heat transfer can not be fully done, the optimum flow velocity is 3 m/s; The larger D is, the shorter the time required to reach the same Q is, but the larger tube diameter will lead to the decrease of concrete volume and heat storage, and the best tube diameter is 25 mm; with the increase of v, the temperature required to reach the same h is lower; h decreases with the increase of D, and the larger D is, the higher the temperature required to reach the same h is. By optimizing the tube type and adopting Sshaped heat exchanger tube, the convective heat transfer coefficient, heat storage and heat storage efficiency are higher than that of straight heat exchanger tube.

TK512

国家自然科学基金项目（51866011）