变汽温试验参数对高中压缸间轴封漏汽量计算的影响分析

Impact and its Analysis of Experiment Parameters of Variable Steam Temperature Experiment on Intermediate Shaft Seal Steam Leakage calculation

针对亚临界330MW机组和超临界660MW机组,研究了高中压缸间轴封漏汽量计算值与变汽温试验参数的关系。对于亚临界330MW机组,试验时主汽温和再热汽温的温差不同,高中压缸间轴封漏汽量占主蒸汽流量的百分比从0.49%到2.42%,实际中压缸效率从89.89%到90.41%;对超临界660MW机组,高中压缸间轴封漏汽量占主蒸汽流量的百分比从0.81%到1.53%,实际中压缸效率从88.79%到89.26%;随着轴封漏汽量增大,实际中压缸效率降低。亚临界330MW机组,由于试验时温差较小,不同的工况组合,实际中压缸效率和高中压缸间轴封漏汽量变化较大;两种容量的机组,降低主汽温度工况和额定参数工况组合,得到的轴封漏汽量都偏差较大。通过计算轴封间隙通流能力,以及对比设计值和试验结果,确认变汽温工况试验时,主汽温度和再热汽温度的试验温差应该达到15℃以上,才能得到较为准确的高中压缸间轴封漏汽量和实际中压缸效率。

For 330MW subcritical unit and 660MW supercritical unit, the relationship is studied between shaft seal steam leakage calculation value and the variable steam temperature experiment parameters, and the shaft seal steam leakage happens between high pressure （HP） and intermediate pressure （IP） cylinders of steam turbine. For 330MW subcritical unit on the experiment case of variable temperature difference between main steam（MS） and reheat steam（ RS）, the shaft seal steam leakage percentage of main steam flow is from O. 49% to 2.42%, and the real percentage of IP cylinder efficiency is from 89.89% to 90.41%. While for 660MW supercritical unit, the shaft seal steam leakage percentage of main steam flow is from O. 81% to 1.53% ,and the real percentage of IP cylinder efficiency is from 88.79% to 89.26%. So the IP cylinder efficiency is reducing with the shaft seal leakage increasing. For 330MW subcritical unit, actual IP cylinder efficiency and shaft seal steam leakage vary greatly on different experiment case combinations because the temperature difference is smaller. For these two capacity unit, the deviation of the shaft seal steam leakage is larger, which is achieved by combination of decreasing MS temperature case and rated parameter case. By calculating the flow capacity of shaft seal clearance and comparing design value with experiment result, we confirm that the shaft seal steam leakage and actual IP cylinder efficiency can be obtained more reasonably only when the difference of MS and RS temperatures on variable steam temperature experiments.