高温高压氢气在三角凹槽及管内流动换热研究

Investigation on flow and heat transfer of high temperature and high pressure hydrogen in triangular grooves and tubes

采用数值模拟方法对高温高压条件下氢气在均匀热流密度加热的长直圆管道和带三角凹槽强化圆管内的流动换热特性进行了研究,模拟中考虑了氢气的物性随温度和压力的变化,湍流模型采用SST k—ω模型。该模型的分析结果与相关文献圆形通道内的实验数据吻合度较高。分析结果表明,氢气在通道中的流动属于亚音速湍流,冷却通道壁面温度沿轴向先逐渐上升在靠近出口时略微下降;圆管内壁上的三角凹槽作为扰流元对氢气流动时的强化换热作用明显,同时增加了流动阻力;增大槽深、减小凹槽间距和非对称三角凹槽使得综合换热性能降低;内凹型带三角凹槽强化圆管的强化换热能力优于外凸型。

Under high temperature and high pressure conditions,the flow and heat transfer characteristics of hydrogen in long straight tubes heated by the uniform heat flux and triangular fluted enhanced tubes were studied by the numerical simulation method.The change of thermophysical properties of hydrogen with temperature and pressure was considered in the simulation,and the SST k-ω turbulence model was adopted.The numerical results of this model are in good agreement with the experimental data in the circular channel of related literature.The results show that the flow of hydrogen in the cooling channel is subsonic turbulence,and the wall temperature of the cooling channel gradually increases along the axial direction and then slightly decreases near the outlet.The triangular groove on the inner wall of the circular tube as the turbulator has an obvious effect on enhancing the heat transfer but increasing the flow resistance.Increasing groove depth,decreasing groove spacing and asymmetric triangular groove reduce the overall heat transfer performance.The enhanced heat transfer performance of the inward triangular fluted enhanced tube is better than that of the outward triangular fluted enhanced tube.