跨声速涡轮叶栅激波损失控制方法

为了降低高负荷跨声速高压涡轮激波损失,发展了针对性的涡轮叶栅激波控制方法。针对吸力侧激波,提出可控膨胀设计概念,结合基于曲率的叶型设计方法,通过调整吸力面曲率分布以控制气流膨胀力度,减小了尾缘激波前马赫数,有效减弱了吸力侧激波强度和叶栅出口压力不均匀程度。针对压力侧激波,发展了消波设计方法,在吸力面的激波作用区域设计一鼓包型线,利用鼓包迎风面压缩波的预增压作用和外凸面膨胀波的消波作用,有效抑制了激波/边界层相互干扰,显著削弱了反射激波强度。可控膨胀设计和消波设计对叶栅尾缘两道激波的控制作用相互独立,可单独采用,当两种方法相结合时,吸力侧激波强度降低了29.66%,叶栅出口压力不均匀程度减小了29.28%,总压损失系数减小了12.11%。 

Shock loss control methods for transonic turbine cascades

Two shock control methods were presented in order to reduce the shock loss in highly-loaded transonic high pressure turbines. For the suction side shock, the controlled expansion designed concept, combined with a curvature based blade design method, was brought forward to control the flow expansion by adjusting the curvature distribution on the suction surface. The suction side shock strength and the pressure non-uniformity at the cascade outlet were effectively reduced with the decreased pre-shock Mach number at the trailing edge. The reduced shock method based on a bump designed on the suction surface was developed to control the pressure side shock effects. The shock/boundary-layer interaction and the reflected shock were obviously weakened with the pre-compression effect and the weakening effect as a result of the bump induced compression waves and expansion waves. In addition, analysis of controlled expansion and reduced shock methods indicated that their controlling effects on two shocks were independent, and thus could be used separately. With the combined shock control methods, numerical results showed a 29.66% reduction in the suction side shock strength, a 29.28% reduction in the pressure non-uniformity at the cascade outlet and a 12.11% reduction in the total pressure loss coefficient for the improved profile.