旋转盘腔盘罩间隙比的敏感性分析

为保证寿命限制件之一的涡轮盘满足适航性要求,采用单向流固耦合(fluid structure interaction,简称FSI)数值方法,研究转静系旋转盘腔盘罩间隙比的变化对转盘安全性的影响机理.并且,由流阻、换热效果和应力分布三方面构成的工程评价体系对盘罩间隙比的影响进行评价以及敏感性分析.结果表明:盘罩间隙比的变化能够影响旋转盘腔内流动结构的强度,从而改变盘面换热效果和转盘温度分布,导致与温度梯度相关的热应力也发生变化.随着盘罩间隙比的增加,旋转盘腔的流阻损失基本不变,转盘迎风面平均换热效果呈现先增强后减弱的趋势,转盘整体应力水平上升,以及出现在盘心处的最大等效应力值增大.盘罩间隙比的变化能够从材料许用应力和实际使用载荷两方面影响涡轮盘的失效概率,因此,在涡轮盘腔设计阶段,需考虑盘罩间隙比对涡轮盘安全性的影响.

Sensibility analysis of gap ratio in rotating cavity

The sensibility analysis of the gap ratio was investigated on the cooling effect of the rotating cavity with intent of ensuring safety of a turbine disk,one of the life-limited parts in the propulsion system.The cooling effect was evaluated by fluid-structure-interaction numerical method according to resistance evaluation,heat transfer evaluation and stress distribution evaluation.The results show that the gap ratio has a great effect on heat transfer and temperature distribution of the rotating disk.Furthermore,the thermal stress of the rotating disk related to the temperature gradient can be affected.As the rising of the gap ratio,the frictional windage of the rotating cavity has not changed,heat transfer of the windward of the disk takes on up-down tendency,and the stress level and the maximum value enlarged.Therefore,change of the gap ratio has an effect on the failure probability of the turbine disk from two aspects:the material affordability and the working stress.