抽汽对抽背式汽轮机性能影响的数值研究  

Numerical Investigation on Influence of Extraction on Performance of Extraction and Back-Pressure Steam Turbines

作　　者：白昆仑 平艳 杨长柱[1] 江生科[1] BAI Kunlun;Ping Yan;YANG Changzhu;JIANG Shengke(Dongfang Turbine Co.,Ltd.,Deyang 618000,China)

机构地区：[1]东方汽轮机有限公司,德阳618000

出　　处：《热力透平》2023年第4期282-288,共7页Thermal Turbine

摘　　要：抽背式汽轮机抽汽流量大、抽汽口数量多,研究抽汽对通流性能的影响对机组优化设计具有重要意义。以某抽背式汽轮机典型抽汽口为例,采用数值仿真方法,研究了2种不同抽汽结构下抽汽流量对前后级效率、抽汽压损和转子受力的影响。结果表明:抽汽对上游级效率几乎没有影响,对下游级效率有一定影响;随着抽汽流量占比增加,抽汽后一级静叶损失逐渐增大,动叶损失先减小后略微增大;抽汽压损随着抽汽流量占比的增加而增大,抽汽流量占比小于20%时,结构2的压损更小,抽汽流量占比大于20%时,结构1的压损更小;抽汽对转子受力波动的影响很小。总体来看,结构1适用于抽汽流量占比较大的机组,结构2适用于抽汽流量占比较小的机组。研究成果可为抽背式汽轮机设计提供有益参考。Extraction and back-pressure steam turbines have large steam extraction quantity and many extraction openings,so the study on the influence of extraction on flow path performance has significance for design and optimization of turbine.Taking a typical extraction opening as the research objective,the influence of extraction quantity on stage efficiency,extraction pressure loss and force on rotor is investigated with two extraction structures,and numerical simulation is used in the calculation.The results show that the extraction has almost no effect on the efficiency of upstream stages,and has certain influence on the efficiency of downstream stages.With the increase of extraction quantity ratio,the loss of first stage stationary blade behind the extraction opening increases gradually,while the rotating blade loss decreases firstly and then increases a little.The larger the extraction quantity ratio is,the higher the extraction pressure loss is.When the extraction quantity ratio is lower than 20%,the pressure loss of structure two is relatively lower,however,when the extraction quantity ratio is above 20%,the pressure loss of structure one is lower.The influence of extraction on the force fluctuation on rotor is limited.In general,structure one is appropriate for units with high extraction quantity ratio,while structure two is more suitable for units with low extraction quantity ratio.The research results can provide reference for design of extraction and back-pressure steam turbines.

关 键 词：抽汽 汽轮机 压损 效率 

分 类 号：TK262[动力工程及工程热物理—动力机械及工程]