工业汽轮机焊接式排汽缸气动特性分析

Analysis on Aerodynamic Characteristics of Welded Exhaust Hood of Industrial Steam Turbine

针对工业汽轮机拖动用领域中的大型焊接式排汽缸,采用数值仿真方法对排汽缸内的流动特性、气动性能、流量特性与不同的撑管结构进行了计算与分析。揭示了大型焊接式排汽缸内的流场结构,分析了新型水滴型撑管对排汽缸气动性能的增益效果。同时,研究了变工况下排汽缸内流体在发展过程中的流量分布特性。研究结果表明:排汽缸上游汽流主要以通道涡状态流动,并以逆向涡对结构流出排汽缸;采用水滴型撑管可以显著改善排汽缸的气动性能;排汽缸入口的周向速度对排汽缸出口的流量分布会产生重大影响。

Aiming at the large welded exhaust hood used in the field of industrial steam turbine drive,the flowing characteristics,aerodynamic performance,flow characteristics and different support pipe structures in the exhaust hood are calculated and analyzed by numerical simulation method.The flowing field structure in the large welded exhaust steam is revealed,and the effect of the new type of water drop supporting tube on the aerodynamic performance of exhaust hood is analyzed.At the same time,the flowing distribution characteristics of the fluid in the exhaust hood under the off design condition are studied.The results show that:the upstream flow of exhaust hood mainly flows in channel vortex state,and flows out of the exhaust hood by reverse vortex pair structure;the aerodynamic performance of exhaust hood can be significantly improved by using water drop type support tube;the circumferential velocity at the exhaust hood inlet has a significant impact on the flow distribution at the exhaust hood outlet.