中间分隔轴封漏汽及中压缸效率计算方法

Research on Calculation of N2 Leakage and Intermediate Pressure Turbine Efficiency

根据中间分隔轴封漏汽的数值计算法推导出漏汽率的误差分析公式。利用变汽温法与数值计算法,对600MW超临界汽轮机的中间分隔轴封漏汽率进行了详细计算。结果表明,相对于变汽温法,数值计算法同样能够准确地估算漏汽率的大小;并分析了温度、压力等测量参数误差对该漏汽计算的影响,计算显示,再热蒸汽温度和中压缸排汽温度是影响中间分隔轴封漏汽率精度的主要因素。同时计算了该机组高压缸排汽平衡盘漏汽量及其对中间分隔轴封漏汽计算的影响,分析证明,接往中压缸排汽区的高压缸排汽平衡盘漏汽对中间分隔轴封漏汽计算的影响较大。在考虑以上2股漏汽后,准确地计算了中压缸效率,计算结果表明,在相同漏量的情况下,中间分隔轴封漏汽对中压缸效率的影响大于高压缸排汽平衡盘漏汽。

Based on numerical calculation method of number 2（N2） leakage,N2 leakage error analysis formulas were deduced.The N2 leakage rate of a 600 MW supercritical steam turbine was estimated with the two methods mentioned above,and the results show that numerical calculation method can estimate N2 leakage as accurately as temperature variation method;moreover,the impact of measured parameters（such as temperature and pressure） error on N2 leakage precision was analyzed,and the analysis shows that the measured parameters chiefly affecting N2 leakage calculation accuracy are reheat temperature and intermediate pressure（IP） turbine exhaust temperature.Meanwhile,N1 leakage quantity and the impact of this leakage on N2 leakage precision were computed,analysis proving that N1 leakage has relatively big influence on N2 leakage precision.The IP turbine efficiency was calculated exactly,with the two leakages computed above taking into account,and the results make clear that N2 leakage has greater impact on IP efficiency than N1 leakage.