Abstract: In order to study the difference between steady calculation and unsteady calculation in the different axial clearances for showing that it is necessary to do the unsteady calculation and analysis in the turbine design,a high-loaded LP turbine was used for the numerical simulation on both steady and unsteady flow in the different axial clearances. And through analysing the effects of the axial clearances flow on the turbine aerodynamic performance in the rotor-stator interaction condition,the steady condition was compared to show the necessity of the unsteady calculation and analysis. The results show that only in a certain axial clearance range,the steady numerical results have a good reference value. Increased axial clearance makes both of the positive and negative incidence angle decrease. It is good for the improvement of the rotor flow condition. Momentum mixing loss in the unsteady flow has a converse effect. It makes the end transverse pressure gradient decrease and it results in the secondary flow loss being reduced.

Key words: Low-pressure turbine；Axial clearance；Rotor-stator interaction；Numerical simulation

摘要： 为了研究不同轴向间距下定常计算与非定常计算间的差异,以表明在涡轮设计中进行非定常计算与分析的必要性,对高负荷低压涡轮级进行了在不同轴向间距下的定常和非定常流动的数值模拟研究,并通过分析动静干涉条件下轴向间距变化对涡轮气动性能的影响并与定常条件下间距变化对气动性能的影响进行对比。结果表明:只有在某个合适的轴向间距范围内,定常计算结果才具有较好的参考价值；轴向间距的增加使得动叶正、负攻角都有减小的趋势,有利于改善动叶的流动状况；非定常流动的动量掺混损失具有其逆效应,它使动叶端部横向压力梯度减弱,二次流损失下降。

关键词: 低压涡轮；轴向间距；动静干涉；数值模拟