Coupling Flutter of Circular Cascading Blade Rows with Splitter Blades.

Present paper aimed to analyze the coupled torsional and bending flluter of a compressor circular cascade composed of main and splitter blades. From the theoretical treatment of the analysis, the unsteady forces and moments of blades carried out a combined motion of torsion and bending are calculated for the main and splitter blades. Numerical examples of the circular cascade composed of nine main blades and nine splitter blades having the same damping coefficients are presented. The flutter velocity is calculated from the flutter determinant which has maximum reduced frequency. The main results are as follows. When the interblade phase parameter of vibration is small, the chord length of the splitter blades is decreased, which reduces the flutter region. Flutter occurs at the vibrating frequency of the blade close to the harmonics of the rotating speed of blade rows. The flutter velocity decreases as the vibration changes from the torsional mode to the bending mode, and increases at a certain chord length of the splitter blades.