太阳能斯特林热机渐开线管簇式吸热器设计与性能仿真

Design and Performance Simulation of Involute Cluster Pipe Type Heat Absorber for Solar Stirling-engine

针对太阳能斯特林热机直接照射型管簇式吸热器,采用等温分析法与湍流强制传热理论,综合考虑加热管簇的通流容积、工质的流阻损失和加热管簇传热能力,得到了基于基本输入热与基于最佳长径比的加热管簇换热长度与管数的定量设计公式.在此基础上,以改善光热转换特性为目的构建了一种新型加热管簇空间位置曲线方程,并以有效功率1 k W太阳能斯特林热机加热管簇设计为例建立了该加热管簇的三维实体模型.通过Fluent仿真分析了该加热管簇的流动与换热特性.结果表明:1 k W有效功率管簇式吸热器所需加热管数为28根,单根加热管长度为31 cm;渐开线加热管结构避免了管内工质流动出现二次流,降低了加热管弯管部分工质压力损失;加热管管壁温度分布相对均匀.

For a pipe-type direct-illumination solar receiver of stirling-engine,the quantitative design formula of the heat transfer length and pipe number of the heating pipe cluster based on the basic input heat and the optimal length-diameter ratio was obtained based on isothermal analysis method and turbulent forced heat transfer theory. This method was the trade-off between flow volume of heat pipe cluster,flow resistance loss of the working fluid and the heat transfer capacity of heat pipe cluster. A new equation of curve of the spatial position of heat pipe cluster was constructed for the purpose of improving the characteristics of light and heat conversion. The three-dimensional model of the heat pipe clusters whose effective power equals 1 kW was established and the flow and heat transfer characteristics of heat pipe clusters was analyzed by Fluent simulation. The results are as follows: the number of heat pipe is 28 required by 1 kW effective power heat pipe-type solar receiver and the length of single heat pipe is 31 cm;the secondary flow phenomenon of working fluid is not easy to produce due to the involute heat pipe structure and pressure drop of working fluid in bending parts of heat pipe is decreased;the temperature distribution of heat pipe wall is relatively uniform.