汽轮机中间分隔轴封漏汽对热耗率影响的分析与计算

利用小偏差理论,分析了汽轮机定主蒸汽流量时,中间分隔轴封漏汽量变化对汽轮机各缸做功量、过再热吸热量以及热耗率的影响。结果表明,当中间分隔轴封漏汽量变化时,汽轮机高压缸做功量与再热吸热量变化较大,中低压缸做功量变化较小。同时,对某台超临界660 MW机组进行了变工况计算。结果显示,当中间分隔轴封漏汽量增加时,汽轮机各段做功量、再热吸热量及热耗率近似线性变化,各部分的变化情况与理论分析结果一致,漏汽主要是通过影响高压缸做功和再热吸热量来改变热耗率,但由于低压缸做功量占汽轮机总功量的比例较大,其变化对热耗率的影响也不可忽视。

Analysis and Calculation of the Impact of N2 Leakage on Heat Rate

Based on the small deviation theory,the impacts of the change of number 2(N2) leakage on the power of turbines,super heat,reheat and heat rate were analyzed when the steam flow keeps constant.The analysis shows that when N2 leakage changes,compared with IP&LP turbines,the power of HP turbine and reheat changes more greatly.Meanwhile,the calculation of a supercritical 660 MW steam turbine under variable conditions was carried out.The results show that when N2 leakage increases,the changes of the powers of turbines,super heat,reheat and heat rate are approximatively linear;the changes are consistent with the theoretical analysis;the leakage changes the heat rate mainly by changing the power of HP turbine and reheat heat;considering that the power of LP turbine accounts for a large proportion in the total power,the impact of the change of the power of LP turbine on the heat rate could not be ignored.