EFFECTS OF S-SHAPED INTAKE ON AEROMECHANICAL CHARACTERISTICS OF A TRANSONIC FAN

被引：0

作者：

Zheng, Yun ^{[1
]}

Xu, Kang ^{[1
]}

Yang, Hui ^{[1
]}

Gao, Qingzhe ^{[1
]}

Jin, Xiubo ^{[1
]}

机构：

[1] Beihang Univ, Sch Energy & Power Engn, Beijing 100191, Peoples R China

来源：

PROCEEDINGS OF THE ASME TURBO EXPO: TURBOMACHINERY TECHNICAL CONFERENCE AND EXPOSITION, VOL 10A, PT I | 2020年

关键词：

S-shaped intake; Aeroelasticity; Inlet distortion; Flutter; Forced response;

D O I：

暂无

中图分类号：

TH [机械、仪表工业];

学科分类号：

0802 ;

摘要：

S-shaped intakes are widely used in aero-engines of modern fighters because of the demand for reducing radar cross-section. Besides, boundary layer ingestion (BLI) configurations are proposed in civil engines recently due to the high propulsion efficiency and low fuel consumption. And S-shaped ducts are usually used as transition sections of diffusers in BLI intakes. Compared with normal straight intakes, it is inevitable to bring in the influence of inlet distortion and acoustic reflection for S-shaped intakes. Meanwhile, composite fan blades, shorter intakes and integrated blisks are common in engine designs. So, fan blades are prone to serious vibrations such as flutter and forced response, which may lead to high-cycle fatigue, and further cause structural failure. The aeromechanical characteristics of a transonic fan (NASA rotor67) in presence of a s-shaped intake are predicted by an in-house integrated time-domain aeroelasticity code. The three dimensional, time-accurate, unsteady Reynolds-Averaged Navier-Stokes equations are solved in fluid domain, and the structural dynamic equations of blade vibration are solved with a modal superimposition method. Mode shapes and natural frequencies of rotor blade are obtained with a commercial Finite Element code, and the Campbell diagram is presented. Full-annulus aeroelastic calculations are conducted to obtain the transient response and the aerodynamic damping of fan blades. Different techniques for interface between the intake and the rotor are used for comparison to demonstrate the influence of upstream interaction. A mixing-plane model is used at the interface to model the blade vibration without interactions with the distortion, while a sliding-plane model is used at the same condition to include the flow distortion and acoustic effects on the fan blade motion. S-shaped intakes with two different axial length are investigated for the forced response and flutter stability. This study indicates that the forced response level is attenuated due to the decrease of distortion level as the length increases, while the flutter stability is determined by the phase difference between the upstream and the reflective acoustic wave.

引用

页数：8