An efficient method on aerodynamic damping coefficient calculation for turbomachinery

It is always difficult to perform aeroelastic analysis on turbomachinery efficiently and precisely due to the complexity of the flow field and structures. The authors develop an unsteady aerodynamic Reduced-Order-Model (ROM) which can be used on small amplitude vibrating blades of turbomachinery. Based on this ROM and classic energy method, an efficient method on aerodynamic damping coefficient calculation for turbomachinery is introduced. With this method, only one unsteady CFD computation is needed to calculate the aerodynamic damping coefficients at all Inter Blade Phase Angles (IBPA) under one specific modal and frequency. The aeroelastic characteristics of STCF4 and NASA Rotor 67 are analyzed by using this ROM with classic energy method. The numerical results indicate that the aerodynamic damping coefficients attained by ROM and unsteady RANS method agree well with each other in the condition of small amplitude of vibration. The efficiency is improved by almost 10 times than multi-passages RANS method. In addition, this ROM can be used in aeroelastic analysis with mistuning effects.