前言大功率汽轮机末级的焓降约占机组总焓降的10％,末级在设计工况下的性能好坏直接关系到机组的热耗率。在汽轮机变工况(高排汽压力或低负荷)下,末级性能的变化最大,机组的经济性和安全可靠性又密切与末级相关。因此,国内外制造厂家都十分重视末 Introduction The final enthalpy drop of high-power turbine accounts for about 10% of the total enthalpy of the unit. The performance of the final stage under the design conditions is directly related to the unit heat rate. In the turbine working conditions (high exhaust pressure or low load), the final performance changes the most, unit economy and safety and reliability are closely related with the final level. Therefore, domestic and foreign manufacturers attach great importance to the end