Fundamental Study on Gyro Moment Matrix in Mode Synthesis Model for Rotary Machine

Abstract

Common turbines have long blades to radial direction and thin to axial side. Then, gyro moment matrix has been approximated as same as a thin disk, whose gyro factor is nearly equal to 2. However, in case of cone type and cylinder type impeller, the approximation does not follow the actual situations. Thus, in this report, fundamental expression of gyro moment matrix in mode synthesis model for rotary machine is discussed. Validity of proposed expression is examined with several types of blade-shaft coupling model by comparing with 3D-FEM model. Further, derivation method of gyro moment matrix with modal participation factor calculated by 3D-FEM software NASTRAN® is discussed.