汽轮机末级叶片颤振设计

Flutter Design for Steam Turbine Last Blade

随着汽轮机的大型化和多样化,汽轮机的叶片振动安全性会出现新的问题,叶片会在非共振强迫振动下产生振动疲劳破坏。研究表明,这是一种叶片颤振。目前,预估汽轮机叶片失速颤振的简化方法有:半经验法、经验法和三维粘性失速颤振数值解法。本文从微分方程稳定性原理出发,阐明了叶片颤振的机理。介绍了几种预估末级叶片颤振的方法,变形激盘法是作者早期与北航共同开发的一种半经验法,已用于工厂叶片颤振设计。并根据作者的经验,推荐了几种经验法来预估叶片的颤振特性。

The blade vibration security appears a new problem along with the hugeness and diversification of steam turbine. The vibration fatigue breakage in the last blade can be engendered on non-resonance of force vibration. The research indicates it is a blade flutter. At present the simplified method for estimating stall flutter of steam turbine last blade flutter has half-experience method, experience method and three dimensional viscous flow numerical analysis stall flutter in steam turbine blades. This paper elucedates the blade flutter mechanism from stability principle of differential eguation. Also a few methods for estimating stall flutter of last blade is introduced. The ＂ distortion disc method＂ is a half-experience method developed by the author and Beijing Aviation Institute. It is used in the blade flutter design. Some experience methods used to estimating stall flutter characteristic are suggested.