轮盘质量和位置对转子临界转速灵敏度分析

为提高火电机组效率,降低污染物排放量,汽轮机组在通流改造中级数有所变化,使转子质量和质心位置发生改变,导致转子临界转速变化,对运行造成一定影响。针对此问题,利用试验测量了不同轮盘质量和位置的转子临界转速,并与理论计算结果进行了比较分析,引入灵敏度分析方法分析了轮盘质量和位置变化对汽轮机转子临界转速的影响。试验研究得出了与理论分析吻合的结论,即转子临界转速随着轮盘质量的增加而减小,随着轮盘偏置量的增加而增加。轮盘偏置量对临界转速的灵敏度系数在0.25~2.4之间,偏置量越大,灵敏度系数越大;质量对临界转速的灵敏度系数在-0.35~-0.001之间,质量增加比例越大,灵敏度系数越小;偏置量对临界转速的影响远远大于质量的影响,大约是7~10倍;同一质量轮盘偏置量大于40%,对转子临界转速改变量较明显;同一偏置位置,质量增加量小于50%,对转子临界转速改变量较明显。这些结论为解决现场汽轮机转子临界转速的调整起到了借鉴作用。

Sensitivity Analysis of Wheel Quality and Location on Rotor Critical Speed

To improve the efficiency of thermal power unit and reduce the pollutant emissions, the steam turbine unit in series of transformation on flow is changed, the quality and center position of mass of the rotor is changed, which leads to the change of rotor critical speed and a certain effects on the run. In this paper, using the experiment to measure the different wheel quality and position of the rotor critical speed, the results are compared with the theoretical calculation result analysis, and the sensitivity analysis methods is introduced to analyze the influence of the quality of wheel and position on changing of steam turbine rotor critical speed. Experimental study agrees well with the theoretical analysis: the rotor critical speed is decreased with the increasing of the wheel quality and is increased with the increasing of the wheel offset. The sensitivity coefficient of wheel offset on the critical speed is between 0.25 and 2.4, the greater the offset, the higher the sensitivity coefficient; the sensitivity coefficient of the quality on the critical speed is between -0.35 and -0.001, the greater the increasing ratio of the quality, the smaller the sensitivity coefficient; the influence of the offset on the critical speed is far greater than the influence of the quality, which is about 7~10 times. When the quality offset of the same wheel is greater than 40%, and the rotor critical speed changes obviously. In the same offset location, the increasing of the mass is less than 50%, and the rotor critical speed changes obviously. The method proposed can be used to solve the problem of the adjustment of the steam turbine rotor critical speed.