ORC向心透平静叶栅内二次流结构和损失分析
2017-10-17尹立冰刘艺苗焦庆雅屈海涛
王 智, 尹立冰, 刘艺苗, 焦庆雅, 屈海涛
(华北电力大学 电站设备状态监测与控制教育部重点实验室,河北保定 071003)
ORC向心透平静叶栅内二次流结构和损失分析
王 智, 尹立冰, 刘艺苗, 焦庆雅, 屈海涛
(华北电力大学 电站设备状态监测与控制教育部重点实验室,河北保定 071003)
为了改进有机工质朗肯循环(ORC)向心透平静叶栅的气动性能,对ORC向心透平内有机工质流动进行三维黏性数值模拟,分析静叶栅上下端壁和通道内各种涡系的表现形式,给出了沿轴向和径向方向的总压力损失系数分布.结果表明:静叶栅内存在压力面与吸力面之间的横向流动,但通道涡并没有形成,通道涡并不是ORC向心透平静叶栅内二次流涡流形式中的重要涡系结构;主要总压损失沿流向方向集中在静叶栅后0.4流向位置,沿叶高方向集中在上下端壁,沿周向方向则聚集在吸力面附近.
向心透平; 静叶栅; 二次流损失; 涡系结构; 有机工质; 数值模拟
Abstract: To improve the aerodynamic performance of stator cascades in radial inflow turbines, three-dimensional viscous numerical simulation was carried out for the flow of organic working fluid in a radial inflow turbine. The forms of various vortices on lower and upper end walls and in the stator cascade passage were analyzed in detail. Meanwhile the distribution of total pressure loss coefficient along the axial and radial directions was presented. Results show that there exists a horizontal flow between the pressure surface and suction surface, but no passage vortex is formed, which is not an important vortex structure for secondary flow in stator cascades of ORC radial inflow turbines. The total pressure loss mainly appears in later 0.4 cascade passage in axial chord direction, near lower and upper end walls in blade height direction, close to the suction surface in circumferential direction.
Key words: radial inflow turbine; stator cascade; secondary flow loss; vortex structure; organic working fluid; numerical simulation
有机工质朗肯循环(ORC)向心透平被广泛应用于中低温余热回收发电系统,而ORC向心透平静叶栅则承担了大部分焓降,是决定整机性能优劣的主要部件.有机工质在ORC向心透平静叶栅内的流动极其复杂,通常是有黏性的三维非定常流动,会出现气流的流动分离及以各种涡系形式表现出来的二次流动.
一般认为二次流损失约占透平静叶栅通流总损失的30%及其以上[1].同时,大量研究[2-3]指出,对于不同几何类型的叶栅和不同的边界条……
