叶栅通道内热斑迁移受动静干涉和叶顶间隙高度影响的研究

Effect of Rotor/Stator Interaction and Tip Clearance Height on Hot Streak Migration in Turbine Passage

本文考虑在透平进口存在热斑时,对受动静干涉和叶顶间隙影响的热斑非定常迁移特性以及近壁面区域的热负荷变化规律进行研究。结果表明:热斑在动叶通道中的形态发生较大变化,并存在冷热流体分离现象;在通道涡、泄漏流以及密度梯度产生的次流涡等涡系的联合作用下,压力面侧的热斑流体逐渐向上下端壁延伸,而吸力面侧逐渐向中叶展聚集;随着顶部间隙高度的增大,泄漏涡与通道涡的干涉作用增强,流道中心流体受泄漏涡的挤压而向压力面侧偏移,引起压力面附近温度梯度的增大,同时由于泄漏量的增加,使叶顶附近壁面两侧的传热环境均趋于恶化。

This paper focuses on the unsteady migration of hot streak and the heat load variation near rotor blade surface in a gas turbine with inlet hot streak,which are under the influence of rotor/stator interaction and tip clearance.The results indicate that in rotor passage the shape of hot streak varies greatly,and hot and cold fluid will separate from each other.Under the combined influence of passage vortex,leakage flow and the secondary flow induced by density gradient,the hot streak fluid near pressure side will extend to both endwalls,while near suction side the hot fluid will gather together to mid span.With the increase of tip clearance height,the interactions between leakage flow and passage vortex rise,so the fluid in rotor passage will be squeezed by leakage flow and migrates towards pressure side,subsequently,the temperature gradient could be raised up near pressure side.Meanwhile,due to the increase of leakage flow,the heat transfer environment along both sides near tip region is further aggravated.