超临界W型火焰锅炉垂直水冷壁低质量流速条件下热敏感性研究

Study on Thermal Sensitivity Characteristics of Vertical Membrane Water Wall in Supercritical Pressure W Shaped Flame Boiler

针对600MW超临界W型火焰锅炉垂直管圈水冷壁在低质量流速下的热敏感特性,对六头内螺纹管垂直水冷壁600MW超临界W型火焰炉热敏感性系数进行研究,分析了干度、热负荷、质量流速及压力等关键参数对超临界W型火焰锅炉内螺纹管垂直水冷壁流量敏感性系数和出口焓敏感性系数的影响规律,并计算和分析了该锅炉水冷壁在不同锅炉负荷下的温度偏差及出口焓值偏差。结果表明随热负荷增大,流量敏感性系数正向增大,锅炉水冷壁自补偿特性增强,出口焓值敏感性系数减小;流量敏感性系数随着质量流速的增大而减小,当质量流速超过一定值时,流量敏感性系数为负,锅炉水冷壁呈现负流量响应特性;质量流速增大,水冷壁出口焓值受热负荷扰动的影响也逐渐减弱;压力的升高有利于锅炉水冷壁水动力稳定性的增强;随干度增大,锅炉自补偿特性减小,出口焓值敏感性系数为正向增大,出口焓值偏差随着干度的增大而增大。研究结果对超临界W型火焰锅炉的安全运行、防止水冷壁爆管具有重要意义。

Thermal sensitivity study was done for 6-head internally ribbed vertical upward membrane water wall of 600 MW supercritical pressure W shaped flame boiler at low mass velocity when heat disturbance occurred.The characteristics of flow sensitivity quotiety and outlet enthalpy sensitivity quotiety were investigated at different heat flux,pressure or mass velocity.Factors which have influence on heat sensitivity of water wall were analyzed in detail.Deviation of flow,enthalpy and temperature of deviation tube were also calculated at different load of W shaped flame boiler separately.The results show that increasing of heat flux leads to an increase in flow sensitivity quotiety and a decrease in outlet enthalpy sensitivity quoiety,and enhances the selfcompensating characteristic of water wall.Increasing of mass velocity decreases flow sensitivity quotiety,and the water wall appears a minus mass flow characteristic when mass flow exceeds a certain value.The hydrodynamics stability of water wall is enhanced by rising pressure.The flow sensitivity quotiety decreases with an increase of steam quality,while the outlet enthalpy sensitivity quotiety increases.The results provide some instructive advice and it is helpful for the safe operation of 600 MW supercritical pressure W shaped flame boiler.