小容积流量工况对排汽缸的影响分析  

Analysis of the Influence on the Little Volume Flow Condition for Exhaust Hood

作　　者：王智[1] 刘艺苗 WANG Zhi;LIU Yi-miao(Key Lab of Condition Monitoring and Control for Power Plant Equipment？MOE？North China Electric Power University？Baoding 071003？ China)

机构地区：[1]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,保定071003

出　　处：《汽轮机技术》2018年第5期332-334,339,共4页Turbine Technology

基　　金：华北电力大学中央高校基本业务费专项资金(2014ZD34);国家科技支撑计划(2014BAA06B01);国家自然科学基金(51306059)

摘　　要：汽轮机末级排汽是影响排汽缸运行的关键因素。对汽轮机末级与排汽缸流场进行了数值模拟,得到当末级处于不同容积流量工况时,排汽缸内流动特性及气动性能。结果表明:随着容积流量的减小,排汽缸内流线分布恶化,扩压通道内靠近外导流环区域出现漩涡,其范围及强度随容积流量减小而增加,扩压性能下降;排汽通道流线紊乱度增加,出现复杂涡系,出口截面流动稳定性下降;大尺度漩涡的存在增加了排汽缸能量损失,静压恢复系数下降,总压损失系数增大。The state of exhaust steam in last-stage has an obvious influence on the exhuat hood. A numerical simulation coupled with the last-stage and the exhaust hood was conducted to get the flow characteristics and aerodynamic performance of the exhaust hood while the last-stage was run in different volume flow condition. According the anslysis,the streamline distribution in the exhaust hood deteriorates under the small volume flow condition. As a result of the vortex appears near the external diversion ring in the diffuser and it enhances along with the reduce of the volume flow,the performance of the exhaust hood decreases; there would be complex vortices in the exhaust passage and bring about the decrease of the flow stability in the outlet section; the existence of the scale vortex increases the energy loss in exhaust hood,meanwhile the pressure recoverycoefficient reduces and total pressure loss coefficient increases.

关 键 词：变容积流量工况 耦合计算 排汽缸 末级 

分 类 号：TK263[动力工程及工程热物理—动力机械及工程]