90°弯头内流体压力脉动特性的大涡数值模拟

Large Eddy Simulation of Pressure Fluctuation in 90° Elbow Pipe

以90°弯头在高温气冷堆内的特殊应用为背景,运用大涡模拟方法对90°弯头内的复杂流场进行了数值模拟,并将时均化处理后的结果与实验结果以及RANS稳态模拟结果进行了综合对比。通过对内、外弧面特定监测点的压力脉动信号进行功率谱密度分析,研究了在流动分离和二次流共同作用下弯头内压力脉动的特点。研究结果表明,压力脉动在内、外弧面上的成因不同。内弧面上最大压力脉动功率出现在弯曲角度50°附近区域,主要由流动分离和涡脱落引起;外弧面上最大压力脉动功率出现在弯曲角度12°附近区域,由流体与外弧面的冲击作用引起。

Based on the special application of 90°elbow pipe in the 10 MW High Temperature Gas-cooled Reactor（HTR-10）,the large eddy simulation was used to compute the complex flow field in 90°elbow pipe.The time-averaged results were compared with the experimental results and the RANS results.The pressure fluctuation signal of the specific test point on intrados and extrados was processed by Fourier transform to get the power spectral density.Under the influence of impact effect,flow separation and the secondary flow,the pressure fluctuation behaves differently on intrados and extrados.The pressure fluctuation on intrados is caused by flow separation and vortexshedding,and the maximum fluctuation amplitude occurs at the bending angle of 50°.On extrados,it is induced by the impact effect,and the maximum fluctuation amplitude occurs at the bending angle of 12°.