小容积流量下汽轮机排汽缸流动特性分析

基于国内外研究现状,建立了汽轮机排汽缸计算模型,设计了100%、43.86%、21.04%3种容积流量工况,分析了排汽缸内的流动特性及涡系特点,得到其静压恢复系数及总压损失系数分布规律。研究表明:随着容积流量的减小,排汽通道后的汽流速度增加,扩压效果减弱,静压恢复系数减小,总压损失系数增大,出口截面不均匀系数增加,流场逐渐恶化。研究结果可为汽轮机排汽缸改型提供参考。

Flow Characteristics Analysis of Steam Turbine Exhaust Cylinder under Small Volume Flow Rate

Based on the current research situation at home and abroad, the calculation model of turbine exhaust cylinder is established. The 100%,43.86% and 21.04% three volume flow conditions are designed. And the characteristics of the vortex system in the exhaust cylinder are analyzed, and the static pressure recovery coefficient and the distribution law of the total pressure loss coefficient are obtained. A technical method to improve the aerodynamic characteristics of the exhaust cylinder is proposed by increasing the inclination angle of the inner guide ring. The research shows that with the decrease of volumetric flow rate, the velocity of steam flow increases after the exhaust passage. The diffuser efficiency of exhaust cylinder is weakened, the static pressure recovery coefficient decreases, and the total pressure loss coefficient increases. The non-uniform coefficient of the outlet section of the exhaust cylinder increases, and the flow field deteriorates gradually. The research results can provide reference for modification of steam turbine exhaust cylinder.