Transient torsional vibration analysis of marine diesel engine under short-circuit impact

Abstract

ObjectivesIn order to formulate an optimization scheme for the torsional vibration parameters of a marine diesel generator shaft system, it is necessary to analyze the transient torsional vibration characteristics of the diesel generator under short-circuit impact.MethodsThe shafting transient torsional vibration characteristics of a 20-cylinder V-type diesel generator set under short-circuit impact are analyzed by the Newmark method, and the effects of different shafting parameters on its shafting transient torsional vibration characteristics under short-circuit conditions are discussed. A new selection scheme of shock absorber stiffness and coupling stiffness is then determined.ResultsThe calculation results show that the shafting torsional vibration characteristics deteriorate significantly when short-circuit impact occurs. After optimization (the stiffness of the torsional shock absorber and coupling are optimized to 90% and 70% of the original value respectively), the maximum transient torque of the motor shaft, maximum transient torque of the coupling and maximum transient stress of each segement of the crankshaft under short-circuit impact conditions are reduced by 13.43%, 10.51% and 5.29% respectively.ConclusionsThe proposed optimized design scheme can effectively reduce the transient torsional vibration level of shaft systems. The results of this study can provide useful references for the vibration and noise reduction design of diesel generator sets.

Keywords

• marine diesel
• shafting torsional vibration
• short-circuit impact
• parameter optimization