【作者】 张鹏；

【导师】 刘波；

【作者基本信息】 西北工业大学 ， 航空宇航科学与技术， 2017， 博士

【摘要】 现代高性能航空发动机对压气机提出了更高的要求,高效率、高单级压比、宽稳定工作范围是未来轴流压气机发展的目标。在轴流压气机中,叶片表面附面层分离流、转子叶尖泄漏流、静子叶栅角区分离流等复杂的流动现象显著影响着压气机效率和稳定工作范围,并限制了压气机级压比的提升。作为一种新型的流动控制技术,附面层抽吸技术可有效控制压气机内部流动,提高压气机负荷。因此,深入研究附面层抽吸技术,对于提升压气机性能、拓宽压气机稳定工作范围有着重要的意义。本文针对附面层抽吸技术开展了以下几个方面的工作:1.针对两套加载类型不同的吸附式叶栅进行了实验研究。研究发现无论加载类型靠前或靠后,在设计来流工况,附面层抽吸可有效降低叶型损失,改善叶栅性能,而对于非设计来流工况,附面层抽吸同样也可以在不同程度上提升叶栅性能。各种来流工况下,随着抽吸量的增大,栅后尾迹区的宽度和深度不断减小,并逐渐向叶片尾缘靠近,表明抽吸后附面层分离减弱,气流转折角增大。2.针对叶片吸力面和角区均存在流动分离的实验叶栅,先后探讨了吸力面抽吸和组合抽吸两种抽吸类型方案,系统研究了不同抽吸槽尺寸、位置和抽吸量对该叶栅性能的影响规律及引起的相应流场变化,并揭示了不同抽吸方案下对应的不同内在流动机制。研究发现,对于仅在叶片吸力面局部叶高进行附面层抽吸,靠前的抽吸槽尽管在叶展中部区域流场改善更大,但同时恶化了端壁区域流场;对于在叶片吸力面全叶高进行抽吸,不同位置的抽吸方案均可以在叶栅全叶展方向改善流动,不同抽吸量下对应的最佳抽吸位置不同;对于不同的组合抽吸方案,本文最佳组合抽吸方案对应的端壁抽吸槽靠近叶片吸力面,且位于叶栅通道马蹄涡吸力面分支与叶片吸力面相交位置之后。3.针对某对转压气机进行了级环境下端壁附面层抽吸的探索,在级环境下首先对前排转子(R1)和后排转子(R2)机匣端壁开槽抽吸,然后对双排转子机匣端壁进行组合抽吸,详细研究了不同抽吸位置、抽吸量对该对转压气机性能、流场结构、稳定工作范围和流动失稳机理的影响。研究发现,R1机匣端壁单独抽吸极大削弱了R1叶尖泄漏流强度,同时改善了R2叶尖区域进口条件;R2机匣端壁单独抽吸时,R1叶片负荷降低,同时使得R2叶尖泄漏流强度显著减小;R1和R2机匣端壁共同抽吸时,其抽吸效果是R1机匣端壁和R2机匣端壁分别单独抽吸效果的叠加。不同抽吸方案下该对转压气机稳定工作范围以及流动失稳机理不同。4.针对某跨声速压气机进行了级环境下端壁附面层抽吸的探索,在级环境下在转子机匣端壁开槽抽吸,详细研究了不同抽吸位置、抽吸量对该跨声速压气机性能、流场结构、稳定工作范围和流动失稳机理的影响。研究发现,端壁抽吸可有效控制转子叶尖泄漏涡,进而改善了下游静子尖部来流条件;端壁抽吸通过有效控制转子叶尖泄漏流拓宽了压气机的稳定工作范围,并改变了其流动失稳机理。随后以该跨声速压气机转子为对象,进一步探索了进气周向总压畸变条件下端壁附面层抽吸提升压气机性能和拓宽其稳定工作范围的有效性,研究表明进气畸变条件下,端壁抽吸同样可有效控制转子叶尖泄漏涡,提升转子的性能,并拓宽其稳定工作范围,同时抽吸后压气机失稳机理发生改变。5.针对高压比吸附式压气机设计方法进行了探索。为实现高压比高效率设计目标,同时为避免在转动部件中进行附面层抽吸所带来的诸如结构强度等问题,对转子采用下压的“S”型机匣型线控制叶尖泄漏流动,并通过全三维气动优化设计改善其内部三维激波结构,提升其内部流场品质;附面层抽吸只在静子中进行,并对静叶采用吸附式叶型反设计,以提高其性能。基于该设计方法,本文仅使用1.5%的抽吸量完成了一台级压比达3.21、效率87.5%的高压比吸附式压气机设计。更多还原

【Abstract】 The modern high-performance aero-engine makes greater demands of compressor,and high efficiency、high stage pressure ratio、wide stable working range are the goals of future axial compressor.In axial compressors,the complex flow phenomena,such as the boundary layer separation flows of blade surface、tip leakage flows of rotor and corner separation flows of stator,have great influence on the efficiency and working stability of the compressors,and limit the improvement of stage pressure ratio.As a new type of flow control technology,the boundary layer suction technology can effectively control the compressor internal flows and improve the compressor load.Therefore,a deep study of boundary layer suction technology is very important to improve the compressor’s performance and working stability.The following research works for boundary layer suction technology are conducted in this paper:1.The experimental research of two aspirated cascades of different loading types was conducted.The study shows that for both loading types,boundary layer suction can effectively decrease profile loss and improve the cascade performance on the design conditions;as for off-design conditions,boundary layer suction also improves the cascade performance in varying degrees.For various conditions,as the suction flow rate increases,the width and depth of the wake curve decrease continuously,and moves closer to the blade trailing edge,which implies a weaker separation and a larger flow turning angle.2.Suction surface suction scheme and combined suction scheme were investigated respectively on the experimental cascade,in which there exist both suction surface flow separation and corner separation.The effects of various suction slot size、location and suction flow rate on the performance and flow field of this cascade were studied systematically,and the various internal flow mechanisms of different suction schemes were revealed.The research results show that for part-span suction on blade suction surface,the front suction slot obviously improves the flow field of middle section,however worsens the flow field in the end wall region.For all-span suction on blade suction surface,all the suction schemes can improve the flows along the whole blade height;different suction flow rates correspond to different best suction locations.For various combined suction schemes,the end wall suction slot of the best combined suction scheme in this paper locates near the blade suction surface and behind the intersection position between the suction branch of passage horse vortex and the blade suction surface.3.The end wall boundary layer suction on a counter-rotating compressor in stage environment was investigated.Through the independent shroud casing suction of the front rotor(R1)and rear rotor(R2)and combined shroud casing suction of them,the influences of suction location and suction flow rate on the performance、flow field、stable working range and flow instability mechanisms of the compressor were studied in detail.The research results show that R1 shroud casing suction greatly weakens the strength of the R1 tip leakage flow and improves inlet flow condition of the R2 tip region.R2 shroud casing suction makes the R1 blade loading decrease and the intensity of R2 tip leakage flow is weakened significantly.Combine suction is the superposition of the dependent suctions.For various suction schemes,the stable working range and flow instability mechanisms of the compressor are different.4.The end wall boundary layer suction on a transonic compressor in stage environment was investigated.Through shroud casing suction of rotor,the influences of suction location and suction flow rate on the performance、flow field、stable working range and flow instability mechanisms of the compressor were researched in detail.The study results show that suction can effectively control rotor tip leakage vortex and thereby improve inlet flow condition of downstream stator tip region.Through effectively controlling rotor tip leakage flow,suction broadens the stable working range of compressor and changes the flow instability mechanism.Then taking the rotor as research object,the shroud casing suction was further studied to explore its effectiveness of improving the performance and widening the stable working range with inlet circumferential total pressure distortion.The research results show that under inlet distortion condition,suction can also control tip leakage vortex well,improve the rotor performance,widen its stable working range,and alter the flow instability mechanism.5.The design method of high pressure ratio aspirated compressor was investigated.In order to achieve the design goal of high stage pressure ratio and high efficiency and meanwhile avoid the structural strengthen problems caused by boundary layer suction in the rotating parts,the pressed down ―S‖ shape shroud casing line was adopted to control the rotor tip leakage flow,and the three-dimensionally aerodynamic optimization was conducted to improve the inner shock wave structure and flow field quality in the rotor;while boundary layer suction was only used in the stator,and meanwhile the stator airfoil was designed by aspirated inverse design to improve the stator performance.Based on this design method,an aspirated compressor which achieves a total pressure ratio of 3.21 and an isentropic efficiency of 87.5% was designed using only 1.5% suction flow rate.更多还原