进口漩流对透平排汽缸内部流动的影响

INFLUENCES OF INLET SWIRL ON NON-AXISYMMETRIC FLOWS IN TURBINE EXHAUST HOODS

使用CFD软件CFX数值模拟了不同漩流条件下大功率汽轮机低压排汽系统实验模型内部的复杂三维流动,定义了衡量非轴对称流场周向不均匀程度的周向不均匀系数。通过对不同漩流条件下计算得到的总压损失系数、静压恢复系数、周向不均匀系数以及缸内流场的对比分析,发现来流在不同径向位置处的漩流角对排汽缸内流动有不同的影响,在此基础上提出了能改善排汽缸气动性能的来流切向气流角分布并进行了数值验证分析。

The complex 3D flow in a steam turbine exhaust hood model has been simulated by employ- ing CFX,one of the computational fluid dynamics (CFD) software.Circumferential non-uniformity coefficient is defined to evaluate the non-uniformity of non-axisymmetric flow.The hood aerodynamic performance,including total pressure loss coefficient,pressure recovery coefficient,circumferential asymmetry coefficient and flow-field in the hood under different inlet swirl conditions has been com- pared and analyzed.It's found that the inlet tangential flow angle at different radial position has different influence on the aerodynamic performances of exhaust hood.To improve the hood perfor- mance,several inlet conditions with optimal tangential ftow angle distribution in the radial direction have been brought forward and then verified by the numerical simulation.