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0.5 H叶高处,0.9 H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。
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 0.5 H blade height,while stress at 0.9 H 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.
作者
司从强
钟达文
王锋
SI Cong-qiang;ZHONG Da-wen;WANG Feng(Beijing Key Laboratory of Passive Nuclear Power Safety and Technology,North China Electric Power University,Beijing 102206,China)
出处
《汽轮机技术》
北大核心
2025年第5期321-328,350,358,368,共11页
Turbine Technology
基金
中央高校基本科研经费资助项目(2024MS051)。
关键词
小流量工况
涡流
湿蒸汽凝结
强度分析
模态分析
low volume flow conditions
vortex
wet steam condensation
strength analysis
modal analysis
