【摘要】 超临界CO₂的太阳能管式集热器通常在高压、高温、高能流密度且非均匀分布的工况下运行,为了探寻有效的流动换热与吸热综合性能强化措施,本文数值模拟研究了5种集热管截面形状对管内超临界CO₂流动换热与阻力性能的影响规律,获得了流动与换热性能、吸热性能、集热管表面温度较低且分布均匀性较优的强化方式。结果表明:1)对于不同截面形状集热管,椭圆形截面集热管的流动换热与吸热综合性能指标（j/f）（q′/q）最优且随长短轴比K的增大而先增大后减小;2)对于不同截面形状集热管表面温度,K最大的椭圆形C截面（K=2.5）的表面最高温度最低,轴向与周向温度分布均匀性最优且K越大越优。更多还原

【Abstract】 In order to seek optimal heat transfer and flow characteristics of supercritical CO₂ flow in a tubular receiver characterized by high temperature, high operating pressure, and non-uniform heat flux, the heat transfer and flow characteristics of supercritical CO₂ flow in 5 tubes with different section shape were studied. The enhanced structures with excellent heat transfer and flow characteristics,heat receiving characteristic, lower and more uniform wall temperature were acquired. The results indicated that: 1) For the comprehensive criterion（j/f）（q′/q）, ellipse section tubes are best. As K（ratio between long and short axes） increases,（j/f）（q′/q） increases first, and then decreases; 2)For the maximum wall temperature and wall temperature distribution uniformity, ellipse section C（K=2.5） tube is the best and becomes better as K increases.更多还原