Intentional Mistuning Effect on the Blisk Vibration with Aerodynamic Damping

Abstract

Intentional mistuning is a well-known factor affecting the vibration of the blisk. This paper mainly focuses on the intentional mistuning effect on the aerodynamic damping and forced response of an axial compressor blisk with random mistuning, and the intentional mistuning types involved in this paper include alternating mistuning, single mistuning, and sector mistuning. The aerodynamic damping of the blisk and its composition are calculated based on the fundamental model of mistuning and influence coefficient method. Under the influence of intentional mistuning, the aerodynamic damping and weight coefficient of each blade in the blisk vary with the modal amplitude and phase. Then, the forced response of the blisk is calculated by the modal superposition method, and the results indicate that intentional mistuning can reduce the increase of forced response caused by random mistuning in two ways: reducing the sensitivity of the blisk to random mistuning and improving the aerodynamic damping of the blisk. Finally, it is found that sector mistuning is better in reducing the sensitivity of the blisk to random mistuning, whereas alternating mistuning is better in improving the aerodynamic damping of the blisk.