空心静叶蒸汽加热除湿传热特性的研究
Study on the Heat Transfer Characteristics of Moisture Removal for Hollow Stationary Blade by Steam Heating

针对空心静叶蒸汽加热除湿过程中加热蒸汽侧凝结换热、叶片固壁热传导以及主流蒸汽侧沸腾换热的传热特性,开展了平板蒸汽加热除湿实验和一维理论分析。研究了主流蒸汽马赫数和加热温差对传热特性的影响,并基于实验数据拟合了蒸汽加热除湿过程的综合传热系数关联式。研究结果表明,一维理论分析得到的综合传热系数与实验值偏差小于10％,可用于汽轮机空心静叶蒸汽加热除湿的方案设计中。主流蒸汽马赫数的增大有利于叶片外表面的水膜蒸发,从而增大主蒸汽侧的沸腾换热传热系数,马赫数为0.28、0.31时,主流蒸汽沸腾换热的热阻最大;马赫数为0？？42时,固壁导热过程的热阻最大。主流马赫数是影响综合传热系数的主要因素,加热温差的影响很小,马赫数为0.42时的综合传热系数达到马赫数为0.28、0.31时的2倍左右。
Experimental study and one？？dimensional (1D) analysis are conducted to investigate the heat transfer characteristics of moisture removal for hollow stationary blade by steam heating, which involves the condensation heat transfer on heating steam side, the blade wall heat conduction and the boiling heat transfer on main steam side. The influences of the Mach number of main steam and the heating temperature difference are studied, and the comprehensive heat transfer coefficient of the moisture removal by steam heating is fitted according to the experimental data. It indicates that the deviation of comprehensive heat transfer coefficient between the experimental data and the prediction results based on 1D analysis is less than 10％, which could be applied to the engineering design. The increase in the main steam Mach number is favorable for evaporation of the water film on the outer blade surface and hence increases the boiling heat transfer coefficient. When the Mach number is 0.28 or 0.31, the thermal resistance in the main steam boiling process reaches its maximum. When the Mach number is 0.42, the thermal resistance of the solid wall heat conduction becomes the biggest. The comprehensive heat transfer coefficient is mainly affected by the main steam Mach number rather than the heating temperature difference, and it doubles when the Mach number increases from 0.28 to 0.42