摘要
为了解决用于控制压气机角区分离的旋涡发生器技术存在的不足,以高速扩压叶栅为研究对象,深入探究了利用端壁L形凹槽结构产生的流向涡抑制压气机角区分离的流动控制策略。首先,通过引入标准造型空间和函数叠合思想,为端壁L形凹槽结构发展了一种便捷且通用的参数化建模方法,并基于该方法开展了端壁L形凹槽的优化设计。通过比较原型叶栅和最优方案的流场仿真结果发现:端壁L形凹槽可以通过其产生的槽道分离涡来有效阻挡横向二次流,切断端壁低能流体向角区的供应,从而显著缓解角区反流、阻止角区分离伴生旋涡的形成,能够在宽广的攻角范围内显著改善叶栅的气动性能。对比不同Pareto最优方案的计算结果发现:槽道分离涡的旋涡强度决定了凹槽对横向二次流的控制效果以及引入附加流动损失和堵塞效应的严重程度,这是影响流动控制效果的关键因素。然后,将基于Sobol指标法的灵敏度分析方法与控制变量法相结合分析了设计参数对端壁L形凹槽流动控制效果的影响。结果表明:凹槽切向位置、凹槽深度、上游凹槽宽度和上游凹槽长度对凹槽的流动控制效果影响较为显著;其中凹槽切向位置主要影响槽道分离涡距离吸力面角区的远近,而后三者则主要影响槽道分离涡的旋涡强度。最后,基于以上分析,总结了端壁L形凹槽的设计参数选取原则。
To overcome the shortcomings of current vortex generator techniques used to control corner separation in compressors,we investigate the mitigation of corner separations using the streamwise vortex generated by the Lshaped endwall groove in a high-speed compressor cascade.First of all,a convenient and universal parametric modeling method for the L-shaped endwall groove has been proposed by introducing the standard modeling space and function superposition strategy,and the L-shaped endwall groove optimization was conducted based on this method.The simulated flow fields of the baseline cascade and a Pareto-optimal case have been compared.It was found that the groove separation vortex generated by the L-shaped groove could effectively block the endwall cross flow,cut off the supply of low momentum endwall fluid to the corner region,and therefore significantly mitigated the reverse flow in the corner region and avoid the formation of the corner separation vortex,remarkably improving the cascade performance within a wide range of incidence.Calculated results of different Pareto-optimal cases have been compared.The results show that the strength of the groove separation vortex determines the control effect of the groove on the endwall cross flow and the severity of additional loss and blockage caused by the groove,and thus is the key factor influencing the control effect of the L-shaped endwall groove.Secondly,the influence of design parameters on the Lshaped endwall groove and its mechanism have been analyzed through the combined use of the Sobol indices-based sensitivity analysis method and conventional control variate method.It was found that the control effect of the endwall groove was significantly influenced by four design parameters including the pitchwise location of the groove,groove depth,the width and length of the upstream groove.The pitchwise location of the groove determined the distance between the groove separation vortex and suction-side corner region,while the other three mainly influenced the strength
作者
王博
吴艳辉
黄令举
王子胥
WANG Bo;WU Yanhui;HUANG Lingju;WANG Zixu(School of Power and Energy,Northwestern Polytechnical University,Xi’an 710129,China;Shaanxi Key Laboratory of Internal Aerodynamics in Aero-Engine,Xi’an 710129,China)
出处
《航空学报》
EI
CAS
CSCD
北大核心
2024年第10期82-110,共29页
Acta Aeronautica et Astronautica Sinica
基金
国家自然科学基金(52176045)
国家科技重大专项(2017-Ⅱ-0010-0024)。
关键词
扩压叶栅
角区分离
端壁L形凹槽
槽道分离涡
设计参数
compressor cascade
corner separation
L-shaped endwall groove
groove separation vortex
design parameter
