大子午扩张涡轮的过渡段分离控制设计

Design on Flow Separation and Control in Transition Section of a Large Meridional Expansion Turbine

在现代高性能的航空涡扇发动机设计中,为了提高经济性,采用较大涵道比,导致风扇高度增加较大,高低压涡轮转速差距较大,高低压过渡段采用大子午扩张型线结构,给低压涡轮及过渡段气动设计带来较大的困难。针对此类涡轮设计要求的特点,采用了两种设计方式对原型进行改型,并对两种改型方案进行了数值模拟,从而研究如何控制此类低压涡轮过渡段分离,提高其气动性能。研究表明,采用两种方法都能够有效的改善流动和降低损失,相比之下,前掠宽弦方案更佳。

To improve the economy, larger bypass ratio has been adopted in the turbofan engine design, leading to a larger fan high, larger speed gap between HP and LP turbines. The meridian geometry of the engine will be excurvature at a high degree, which brings problem for the design of LP turbines, transition section between HP and LP turbines. In accordance with such characteristics, adopted two ways to redesign a better turbine, and two modified turbines was simulated to study how to control flow separation of LP turbines and the transition section, improve its aerodynamic performance. The results indicate that adopted the two ways to improve the performance is effectual, but the forward-swept and wide-chord blade technology is more effectual.