为了研究低压缸切缸工况时机组的运行能力，以国内某电厂汽轮机低压缸为研究对象，建立低压缸单边八级叶栅单通道流场三维计算模型，分析不同入口流量下其内部流动结构和气动性能以及末级动叶的鼓风加热特性。结果表明：随着低压缸入口流量的持续减小，排汽出口和末级叶栅内会陆续出现排汽回流和汽流分离现象，并伴随有动叶入口的负攻角现象；当低压缸入口流量减小至1.19%额定流量时，工质做功无法弥补低压缸转子旋转耗功，低压缸整机无法输出功率；当低压缸入口流量降低至7.44%额定流量时，末级通道动静交界面靠近叶顶区域和末级动叶通道靠近叶顶区域出现局部高温区，出现切缸工况末级动叶的鼓风加热效应；同时，切缸工况下末级静叶鼓风加热温度抬高程度显著大于末级动叶，相较于额定工况末级静叶和末级动叶表面最高温度分别抬高了约10596%和71.91%。

In order to study the operation capacity of the lowpressure cylinder cutoff condition, the threedimensional numerical model of the singlechannel flow field of the eightstage cascade of the lowpressure cylinder was established by taking the lowpressure cylinder of the stream turbine in a domestic power plant as the research object, while the internal flow structure and aerodynamic performance of the lowpressure cylinder under different inlet flow rates and the windage heating characteristics of the final moving blade were analyzed. Results show that with the continuous decrease of the lowpressure cylinder inlet flow rate, the exhaust backflow and steam flow separation occur at the exhaust outlet and in the last stage cascade accompanied by the negative attack angle at the inlet of the rotor blade; when the inlet flow rate of lowpressure cylinder is reduced to 1.19%, the work done by the working medium cannot compensate for lowpressure cylinder rotor rotational work, and the whole machine of the lowpressure cylinder cannot output power; when the inlet flow rate of lowpressure cylinder is reduced to 7.44%, a local high temperature region is appeared in the dynamic and static interface of the last stage channel near the top of the blade and in the last stage rotor blade channel near the top of the blade, which is manifested as the windage heating effect of the last stage rotor blade under the cylinder cutoff condition; meanwhile, the last stage stator blade windage heating temperature elevation is significantly higher than that of the rotor blade, compared with the rated condition, the maximum temperatures on the surfaces of the last stage stator and rotor blades under the cylinder cutoff condition are increased about 105.96% and 71.91%.

TK263.1