The Fast Analysis Method For The Aeroelasticity Of Blade Induced By Upstream Wake Based On The ROM Method

In aeroengine,due to the relative rotation of stator and rotor,the downstream cascade is impacted by periodic upstream wake for a long time,which leads to aeroelastic vibration and even fatigue of downstream blades,and finally leads to damage of blade.High performance numerical simulation of CFD/CSM provides a reliable technical means for the study of aerodynamic force and aeroelasticity of blades under wake excitation,but it needs to take a large amount of calculation time.Based on the reviewing for the development of numerical simulation of blade and analysis methods of aeroelasticity of blades,it is studied for the aerodynamic force and vibration of blades under upstream wake excitation by using reduced order model(ROM)method and influence coefficient method(ICM).The main work of this paper is as follows:Firstly,based on the harmonic balance method,the flow field around the blade under wake excitation is studied,and an aerodynamic ROM of the blade under wake excitation is proposed.Meanwhile,the Fluid-Solid coupling analysis method of the blade is proposed by combining the structural motion equation of the blade.The results show that the aerodynamic ROM and Fluid-Solid coupling method based on the aerodynamic ROM of blade,which are proposed in this paper,can quickly and accurately calculate the blade response induced by upstream wake excitation.At the same time,by studying the Harmonic Balance further,it is found that there is an influence coefficient between the amplitude of the aerodynamic force of blade and the amplitude of the wake,which is only related to the wake frequency,under the small disturbance.Based on this discovery,an aerodynamic influence coefficient model(IC-ROM)method,which is based on the aerodynamic ROM of blade,is proposed in this paper.For this method,the influence coefficients between the harmonic amplitude of blade aerodynamic force and the harmonic amplitude of wake caused by several harmonic wakes are obtained firstly,and the curve is fitted between the influence coefficient and the frequency of wake.The amplitudes of the aerodynamic force of blade under the wake is got by the curve and the amplitudes of the wake harmonic,and then the aerodynamic force of blade is solved by the aerodynamic ROM.At the same time,combined with the motion equation of blade centroid structure,a Fluid-Solid coupling analysis method of blade based on the aerodynamic IC-ROM is proposed.The results show that the aeroelastic response of blades under arbitrary wake excitation in a given frequency range can be rapidly and accurately analyzed by the aerodynamic IC-ROM and the Fluid-Structure coupling method based on the IC-ROM,which are proposed in this paper.