【摘要】 以某330MW电厂的汽轮机末级叶片为研究对象，构建了两相流-热-固耦合模型，分析末级叶片在100%THA～5%THA工况下的流场特性和力学性能。研究结果表明：随着负荷降低，在小流量工况下，末级流场存在间隙涡、分离涡、二次涡和回流涡。27.6%THA为零出力工况，20%THA以下出现鼓风效应。100%THA～30%THA工况下，液滴受流场影响主要在叶片的压力面和尾缘区域形成，并随流动逐渐向下游移动；在5%THA工况，液滴仅存在于涡核处。应力、应变分析表明，最大等效应力出现在叶片0.5H叶高处，0.9H处等效应力受流场影响显著。不同工况下叶片最大形变位置都出现在85%叶高附近，与实际叶片断裂位置相近。此外，鼓风效应导致叶片温度升高、压力分布混乱，同时对叶片应力和形变产生影响。模态分析表明，叶片发生共振概率较小。研究结果可为小机组汽轮机调峰改造提供理论参考。更多还原

【Abstract】 This study focuses on the last-stage blades of a 330MW power plant’s steam turbine, and a two-phase flow-thermal-structural coupling model was constructed. The flow characteristics and mechanical performance of the last-stage blades under 100%THA-5%THA conditions were analyzed. The results show that as the load decreases, the flow field under low volume flow conditions exhibitsgap vortices, separation vortices, secondary vortices, and backflow vortices in the last-stage flow. The zero-power condition occurs at 27.6%THA, with windage effects emerging below 20%THA. Under 100%THA to 30%THA conditions, liquid droplets influenced by the flow field primarily form on the pressure surface and trailing edge of the blades, gradually migrating downstream with the flow. At 5%THA, droplets are confined to vortex cores. Stress and strain analyses indicate that the maximum equivalent stress occurs at 0.5H blade height, while stress at 0.9H is significantly affected by the flow field. The maximum blade deformation across all conditions is observed near 85% blade height, consistent with actual blade fracture locations. Additionally, windage effects lead to blade temperature rise, chaotic pressure distribution, and notable impacts on stress and deformation. Modal analysis suggests a low probability of blade resonance. These findings provide theoretical insights for peak regulation of small-scale steam turbines.更多还原