汽轮机低压缸零出力流动与温升特性数值研究  

Numerical investigation on off-design flow and temperature rise characteristics of steam turbine low pressure cylinder

作　　者：翟鹏程 王汀[1,2] 于龙文 穆祺伟 张奔 杨荣祖 王宏武[1,2] 谢天 王耀文 石慧[1,2] 孙添一 李志刚 李军[3] ZHAI Pengcheng;WANG Ting;YU Longwen;MU Qiwei;ZHANG Ben;YANG Rongzu;WANG Hongwu;XIE Tian;WANG Yaowen;SHI Hui;SUN Tianyi;LI Zhigang;LI Jun(Xi’an Thermal Power Research Institute Co.,Ltd.,Xi’an 710054,China;National Key Laboratory of Efficient Coal,Electricity and Carbon Capture,Utilization and Storage,Xi’an 710054,China;Institute of Turbomachinery,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]西安热工研究院有限公司,陕西西安710054 [2]高效灵活煤电及碳捕集利用封存全国重点实验室,陕西西安710054 [3]西安交通大学叶轮机械研究所,陕西西安710049

出　　处：《热力发电》2023年第4期128-134,共7页Thermal Power Generation

基　　金：中国华能集团有限公司总部科技项目(HNKJ21-H71)。

摘　　要：小流量下汽轮机低压缸末级内部流动与温升现象十分复杂,为火电调峰与低压缸零出力改造带来挑战。为此,以某电厂汽轮机低压缸为研究对象,建立了低压缸五级叶栅单通道流场计算模型,数值研究了不同工况下低压缸工作性能、流动结构与温升特性。结果表明:当低压缸通流流量降低至设计工况的3.84%时,低压缸无法输出功率;流量很小时,低压缸进入鼓风状态,末级叶栅出现下端壁分离区、静叶分离区、机匣环面涡、末级动叶涡等流动结构,且在末级叶栅转-静间隙叶顶位置出现显著鼓风加热现象;流量降低至设计工况的2.23%时,末级静叶、动叶表面平均温度分别升高219.6 K与243.7 K。鼓风状态下,低压缸工作性能、内流结构均会发生显著变化,末级叶栅内温度升高使叶片工作环境恶化,机组小流量运行需对其加以考虑。The internal flow and temperature rise characteristics in the last stage of steam turbine low pressure cylinder under low flow rate condition is quite complex, which makes thermal power peak load regulation and cutoff transformation more challenging. By taking the low pressure cylinder of a steam turbine in a power plant as the research object, a five-stage cascade single-channel calculation model of the low pressure cylinder was established,and the working performance, flow structure and temperature rise characteristics of the low-pressure cylinder under different working conditions were numerically investigated. The research shows that, when the flow rate of the lowpressure cylinder decreases to 3.84% of the design condition, the low-pressure cylinder outputs no positive power.When the flow rate is quite low, the low pressure cylinder enters the windage condition, and the flow structures such as the hub endwall separation area, the vane separation area, the casing torus vortex, and the last stage bucket vortex appear in the last stage cascade, by concomitant of obvious windage heating effect at the tip position of rotorstator clearance area of last stage cascade under low flow rate condition. When the flow rate decreases to 2.23% of the design condition, the average surface temperatures of the last stage vane and blade increase by 219.6 K and 243.7 K, respectively. The working performance and internal flow structure significantly change under windage condition. The temperature rise in the last stage cascade deteriorates the working environment of the blades, which needs to be taken into consideration when the steam turbine works under low flow rate condition.

关 键 词：低压缸 数值研究 鼓风状态 流动结构 温升特性 

分 类 号：TM62[电气工程—电力系统及自动化]