间隙高度对某涡轮叶尖间隙泄漏流影响的研究

Influence of Tip Clearance Size on Tip Clearance Flow of a Transonic Turbine

关键词:  涡轮  叶尖间隙  叶尖间隙流  泄露涡  数值模拟

Key words:  Turbine  Tip clearance  Tip clearance flow  Loss vortex  Numerical simulation

摘要:

利用三维湍流数值模拟方法模拟某跨声速高压涡轮流场,研究了转子叶尖间隙高度对涡轮转子间隙泄漏流动的影响,详细描述了间隙流动结构随间隙高度的变化情况。研究结果表明:随着间隙高度的增加,间隙泄漏流流量线性增加,并导致转子叶尖附近流体偏转角度减小。间隙高度每增加1%相对叶高,间隙泄漏流量占总流量的比例约增加2.1%。间隙高度变化对间隙内部流动的影响明显:当间隙比较小时,随着间隙高度的增加,分离泡的大小迅速增加,回流区域减小。随着间隙高度的增加,间隙泄漏涡尺度迅速增加,同时由于泄漏流中高速流体流量增加,通道涡远离叶片吸力面并向靠近机匣的方向移动,泄漏涡也向远离吸力面方向运动。

Abstract:

The influence of the tip clearance height of turbine rotor blades on tip clearance flow of an axial turbine stage was investigated by numerical simulation and different tip clearance heights were taken into account. Results show that the leakage flow rate would increase markedly due to the increase of the tip clearance height. The ratio of the leakage flow rate and total flow rate would increase 2.1% as the tip clearance height increased 1% of the blade height. From analyzing the flow field, it indicates that as the height of tip clearance increases, the flow structure in the tip clearance changes. When the height of tip clearance is small, the size of the separation bubble increases quickly as the height of tip clearance increases, meanwhile, the size of the leakage vortex gets larger as well as the flow rate of high speed leakage flow. The passage vortex and the leakage vortex are pushed off from the blade, the flow structure of secondary flow near the tip clearance changes while the height of tip clearance increases. 