低负荷工况下汽轮机末级通流部分的非定常流动研究  

Unsteady Flow in the Last Stage of a Steam Turbine under Low Load Conditions

作　　者：任宇航 谭洪强 李振辉[1] REN Yuhang;TAN Hongqiang;LI Zhenhui(School of Mechatronical Engineering,Changchun University of Science and Technology,Changchun 130022)

机构地区：[1]长春理工大学机电工程学院,长春130022

出　　处：《长春理工大学学报（自然科学版）》2022年第6期104-109,共6页Journal of Changchun University of Science and Technology(Natural Science Edition)

基　　金：吉林省科技厅项目(20200401098GX)。

摘　　要：汽轮机低压缸末级长叶片在低负荷工况下运行时由于通道内涡流的存在具有明显的非定常性。采用ANSYS CFX对汽轮机末级多通道的非定常流动进行数值模拟计算。分析了末级动叶通道内涡系的结构及其非定常特性。结果表明:分离涡和回流涡为径向涡,其非定常性来源于叶片旋转激励,其压力脉动幅值随流量的减小而减小。10%THA工况下,分离涡与回流涡的频率具有长波低频特征。周向泄漏涡由分离涡在叶顶向动叶前缘泄漏形成,为周向涡。周向泄漏涡存在周向非定常扰动,产生一个非外界激励而引起的非定常性,即涡流自激的非定常性。The last stage blade of low pressure cylinder of steam turbine has obvious unsteadiness due to the existence of vortices in the passage under low load conditions.ANSYS CFX was used to simulate the unsteady flow in the last stage of steam turbine.The structure and unsteady characteristics of the vortices in the last stage passage are analyzed.The results show that the unsteady fluctuation of the separation vortex and the backflow vortex are produced by the rotating excitation.the pressure fluctuation amplitude decreases with the decrease of the inlet mass flow rate.At 10%THA condition,the pressure fluctuations of the separation vortex and the backflow vortex have the characteristics of long wave and low frequency.The circumferential leakage vortex is formed by the separation vortex leaking from the blade top to the leading edge of the rotor blade,which is a circumferential vortex.Circumferential unsteady disturbance exists in the circumferential leakage vortex,which generates an unsteadiness caused by non external excitation,namely the unsteadiness of vortex self-excited.

关 键 词：低负荷 汽轮机末级 涡流 非定常性 

分 类 号：TK262[动力工程及工程热物理—动力机械及工程]