涡轮气动设计对空气涡轮起动机自由运转转速的影响分析

Analysis for Influence of Turbine Aerodynamic Design on Free-Running Speed of Air Turbine Starter

关键词:  空气涡轮起动机  涡轮  气动设计  攻角  自由运转转速

Key words:  Air turbine starter  Turbine  Aerodynamic design  Incidence angle  Free-running speed

摘要:

为控制空气涡轮起动机自由运转，减少自由运转转速过高对空气涡轮起动机结构重量及安全运行带来的不利影响，开展了涡轮气动设计对空气涡轮起动机自由运转转速的影响分析，提出通过控制来流攻角降低自由运转转速的气动设计方法，识别了影响来流攻角的四个主要因素：叶片构造角、反力度、载荷系数和流量系数。结果表明：来流攻角对自由运转转速具有非常明显的影响，通过选择合适的气动参数，可有效提高峰值功率转速下的负攻角，增强大转速状态下的转子攻角损失，进而降低涡轮自由运转转速。进一步，整机试验结果证明，采用本文提出的设计方法，优化后的涡轮在峰值功率基本不变的前提下，峰值功率转速降低17.8%，自由运转转速可降低近20%。

Abstract:

In order to control the air turbine starter free-running operation and reduce the adverse impact of high free running speed on safe operation of the air turbine starter， the influence analysis of the aerodynamic design to the value of free-running speed was carried out. An aerodynamic design method of reducing free running speed by controlling flow incidence angle is proposed and four main factors affecting the incidence angle were identified， which include blade structure angle， degree of reaction， load coefficient and flow coefficient.Results show that the incidence angle has a significant effect on the free-running speed. The negative incidence angle at peak power speed can be effectively improved by selecting appropriate turbine aerodynamic design parameters， and the incidence loss at larger speed can be enhanced， thus reducing turbine free running speed value. Further， the engine test results prove that using the design method proposed in this paper， the peak power speed value of the optimized turbine is reduced by 21.7% on the premise that the peak power is basically unchanged， and the estimated free-running speed value can be reduced by nearly 20%.