Rotordynamics Design of Jet Engine from New Viewpoint

Abstract

Shaft vibration in jet engines has a direct operational cost and also impairs riding comfort with noise etc., making it a primary factor in lowering the level of customer satisfaction. From a safety standpoint, excessive vibration also accelerates fatigue damage to structures and can lead to serious accidents. Rotors have conventionally been designed so that their critical damage speed stays clear of their operational rotation speed area, leaving a certain margin to allow for the effects of variation. However, if vibration is viewed as energy, shaft vibration can be considered as a phenomenon in which a jet engine system loses energy in the form of vibration and the accompanying sound and heat. Suppressing this energy loss, with consideration given to variation, could be expected to improve total system efficiency. In this study, a shaft vibration design from the new viewpoint of minimizing energy loss was attempted. Using Taguchi methods, a design aiming at a system in which energy loss is minimized in the presence of variation was performed and the result obtained was compared with a design performed from the conventional viewpoint.