基于Bezier曲线的端壁造型设计方法研究

Design Method of Endwall Profiling Based on Bezier Curves

关键词:  涡轮导向叶片  非轴对称端壁  设计方法  数值模拟  总压损失系数

Key words:  Turborotor  Non-axisymmetric endwall  Design method  Numerical simulation  Total pressure loss coefficient

摘要:

为探索端壁造型提高涡轮导叶气动性能及改善其流场的潜力，了解端壁造型对高压涡轮级性能的影响，根据非轴对称端壁造型技术的基本原理，提出了一种基于Bezier曲线与三角函数曲线相结合的新型非轴对称端壁造型设计方法，并以一级高压涡轮导叶为研究对象，通过改变幅值的取值，对其下端壁进行了6种不同的端壁造型设计。同时，利用数值模拟方法对造型前后的涡轮导叶在级环境下进行了全三维流场计算。计算及分析表明:合理地进行端壁造型可以有效地减小涡轮导叶通道内的流动损失，并且，在应用该设计方法对涡轮导叶下端壁进行端壁造型时，幅值的取值存在一个最佳值6mm，即10%叶高，此时导叶出口总压损失系数降低了0.94%。然而，非轴对称端壁造型也影响了导叶与动叶之间的相互干涉，从而导致高压涡轮级性能的下降。

Abstract:

With the purpose to deeply research the effect of improving aerodynamic performance and flow field in turbine stator，and to preliminarily understand the influence on turbine stage performance caused by non-axisymmetric endwall，according to the basic principle of non-axisymmetric endwall profiling technology，a novel design method of non-axisymmetric endwall profiling was developed based on the Bezier curves in combination with trigonometric functions. This design method was applied to the hub of one high pressure(HP) turbine stator to construct six different non-axisymmetric endwalls by changing the amplitude values. Subsequently，the three-dimensional flow in original and profiled HP turbine stator were simulated in the condition of whole stage. The analysis results indicate that the appropriately profiled non-axisymmetric endwall can effectively reduce the flow losses in the stator passage and there is an optimum amplitude 6mm，i.e. 10% span when applying this method to the hub of this stator. While the total pressure loss coefficient decreases by 0.94% thanks to the non-axisymmetric endwall，the interaction between stator and rotor is also affected as a consequence of the reduction in the stage performance.