汽轮机末级叶片的气动优化及分析

Aerodynamic Optimization and Analysis for Last Stage of Steam Turbine

文章采用大型商用流体软件——NUMECA,对某大型汽轮机原始设计的低压通流进行了三维数值计算,得到了低压各级的流场分布和气动特性,计算分析结果表明,原始设计的低压末级性能有较大的优化潜力.保持末级动叶不变的前提下,对末级静叶进行轴向前掠,切向弯曲,截面扭转等叶型变换,分析比较各方案对末级效率、排气速度,排气角等气动性能的影响.优化结果表明,对低压末级静叶采用合适的弯掠技术可以改善末级的流场特性,提高末级效率.

3D numerical calculation of the low pressure flow in the original design of a large steam turbine is carried out by using the large commercial fluid software - NUMECA, the distribution of flow field and aerodynamic characteristics of the low pressure stages are obtained. The analysis results show that the performance of the last stage of the original design has great potential for optimization. under the condition that the moving blade is unchanged, the axial sweep, lean and rotate section torsion of the last stage static blade are carried, and the influence of each scheme on the last stage efficiency, the exhaust speed, exhaust angle are analyzed and compared. The optimization results show that the last stage nozzle blade can improve the flow field characteristics and improve the last stage efficiency by suitable sweep technology.