| Compressor blade is one of the crucial parts of aero-engine,which can ensure the safety of aviation flight and the performance of aircraft engine.The combined effect of the aerodynamic force and inertial force and the elastic force makes the total force complex,while rotor blade high speed rotates.Generally applies only to the theoretical calculation model and the stress is relatively simple,for this complex leaf shape and uneven,numerical calculation to ensure efficient calculation accuracy of circumstances to complete the analysis of the problem,so the blade pneumatic elastic numerical simulation has important engineering significance.In this paper,the compressor blade which made of titanium alloy in aero-engine is taken as the research object.Firstly,the research progress on the aerodynamic elasticity of the blade at home and abroad were described.Then the physical model and mathematical model used in aeroelastic analysis are summarized.Secondly,the flow field characteristics in the flow channel where the blade is located are numerically calculated with ANSYS CFX software,and the selected turbulence model is verified with a standard example.Thirdly,the aerodynamic and elastic response of the blade were studied.The compressor blade’s strength,modal and harmonic response were analyzed.The influence of prestress on the vibration modal of the blade is analyzed.Finally,the aerodynamic stability of the blade was studied,and the flutter of the blade is mainly studied whici based on harmonic balance technology of energy method.The major research work and achievement of this paper were showed:(1)Reverse parameterization was carried out on the blade physical model after eliminating parameters,and the physical model required in this paper was established;The mathematical models needed for aeroelastic calculation of blades were described and explained in detail,including three conservation equations,state equation and turbulence model used in flow field analysis,Newtonian structural dynamics equation used in blade structure analysis,and coupling method used in coupling of the two.(2)The characteristics of the flow field in the flow passage where the blade is located are studied.Turbo Grid is used as a tool to divide the flow field grid,and the irrelevance of the divided grid was verified.The characteristics of the blade under different working conditions at rated speed were calculated,and the relationship among pressure ratio,isentropic efficiency and relative mass flow rate were plotted.The analysis results showed that the working condition with the highest efficiency corresponds to the mass flow total pressure ratio is not the highest,and it is difficult to reach a highest state between them.Finally,the accuracy of the SST turbulence model used in the process of flow field analysis was studied by using the Rotor67 model as a verification example.The results show that the SST turbulence model can maintain the same trend with the experimental data.(3)The aerodynamic response of the blade is studied.The strength analysis of the blade was carried out,and the influence of aerodynamic load on blade deformation,stress and natural frequency were analyzed.The analysis results showed that the deformation of the blade is about 0.44 mm which larger than that of the blade without aerodynamic load,but the stress value is 8.6MPa smaller.The vibration modal analysis of the blade showed that the natural frequency with prestress was higher than that without prestress,mainly because the prestress has a "rigid" effect on the blade,but the blade formations of each order are basically the same.The campbell diagram of the blade under prestress was drawn,and the results showed that the blade does not resonance under working conditions.Harmonic response analysis by modal superposition method to analyze,exciting force to the sine law of change of aerodynamic load,the incentive was seted to 0-1900 Hz frequency range,and it can be divided into 19 parts,every 100 Hz impose an incentive.Finally,found that when the excitation frequency and the first order natural frequency is close to,the vibration amplitude of blade in the Y direction up to 1.1 mm.(4)The aeroelastic stability of the blade was studied.The flutter of the blade was mainly analyzed.Firstly,the flutter characteristics was studied.Secondly,the calculation methods used in the flutter analysis were analyzed.Based on the energy method,the work done by unsteady aerodynamic force on the blades in the vibration state was calculated with the idea of harmonic balance,and the aerodynamic damping was calculated with the aerodynamic work.Finally,the aerodynamic damping of the blades at different phase angles in the first three modes is analyzed.The results showed that the blades have no flutter and aerodynamic stability when working at rated speed. |
