摘要
为了揭示轴流压气机转子叶尖非同步气流激励的产生机制,针对某1.5级压气机计算模型,基于分离涡模拟(detached eddy simulation,DES)和非定常Reynolds平均模拟(unsteady Reynolds averaged Navier-Stokes,URANS)方法对近失速工况下压气机全周非定常流场进行了数值模拟,重点分析了压气机转子叶尖非同步气流激励频率、不稳定流动的周向模态特征以及转子叶尖不稳定流动结构。结果表明:近失速工况下,转子叶尖非同步气流激励频率的出现伴随着压力脉动幅值的急剧增加,静压波动幅值可达20%以上,转子叶尖非同步气流激励呈现宽频特征,其频率范围涵盖1.58EO~17.86EO,相对与绝对坐标系下非同步气流激励频率满足频率叠加关系。转子叶片非同步气流激励主要由叶尖吸力面径向分离涡引起,DES数值模拟相比URANS可以获得更精细、更丰富的不稳定涡结构,其周向模态数更高。由于转子吸力面气流分离发生在80%叶高以上区域,因此非同步气流激励出现时压气机转子并未失去做功能力。
In order to reveal the flow mechanism of non-synchronous aerodynamic excitation at rotor tip region of axial compressor,the unsteady flow field of a 1.5-stage compressor under near-stall conditions was simulated using the detached eddy simulation(DES)and the unsteady Reynolds averaged Navier-Stokes(URANS).The non-synchronous aerodynamic excitation frequency,circumferential modal characteristics and unstable tip flow structures were analyzed.The results show that the non-synchronous aerodynamic excitation frequency of the rotor tip region is accompanied by a significant increase in pressure fluctuation amplitude under near-stall conditions,and the pressure fluctuation amplitude can reach more than 20%.The non-synchronous aerodynamic excitation frequency exhibits a broadband characteristic,which covers the frequency range of 1.58EO to 17.86EO.The non-synchronous aerodynamic excitation frequency in the relative and absolute coordinate systems satisfies a frequency superposition relationship.The non-synchronous aerodynamic excitation of rotor blade is mainly caused by the radial separation vortices on the suction surface.DES can obtain more refined and diverse unstable vortex structures,with a higher number of circumferential modes as compared to the URANS.Because the flow separation on the suction surface of the rotor blade occurs in the region above 80%span,the compressor rotor maintains its ability to perform work when the non-synchronous aerodynamic excitation occurs.
作者
汪松柏
赵星
郝玉扬
陈勇
吴亚东
WANG Songbai;ZHAO Xing;HAO Yuyang;CHEN Yong;WU Yadong(School of Mechanical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;AECC Sichuan Gas Turbine Establishment,Chengdu 610500,China)
出处
《气体物理》
2025年第5期63-69,共7页
Physics of Gases
基金
国家科技重大专项(J2022-Ⅳ-0010-0024)。
关键词
轴流压气机
转子叶尖
非同步气流激励
分离涡数值模拟
不稳定流动
axial compressor
rotor tip
non-synchronous aerodynamic excitation
detached eddy simulation
unstable flow
