Compute And Analysis Of Linear Characteristic Of Vibration Of The Shafts Of The Hydroelectric Machines

Shafts are the important part of large hydroelectric machines. Its dynamic characteristic is bound up with the reliability,life-span and economic index of the entire machines. Therefore,it is important to analysis the large hydroelectric machines from the aspect of theory.First,the system boundary of machines affecting the shafts,such as the guide bearings,seal,electrical and hydraulic forces,the water in the runner etc,is analyzed. And the mathematic model of the system boundary of the machine is built. The compute model of shafts of the machines is built by adopting concentrated mass method. Taking into account the different support conditions of the shafts that workshop is considered as rigidity or elasticity;the natural characteristic and unbalanced response of the shafts are computed by integrating with high stable Riccati Transfer Matrix Method.Second,Adopting the linearity of oil film of the guide bearings,the transient response of the shafts is computed and analysis by integrating with Willson method. Because of the uncertain position of the shafts in the guide bearing,the model and solution method of nonlinear transient response of the shafts is discussed.At last,the rotor-bearing system of a Franics hydraulic generator set of the 3rd machine in the NANYA river YAOHEBA factory is used as an example,calculating result and discussion are given by integrating Matlab computeand simulation language. The dynamic response of the shafts is tested by adopting modern testing method and advanced equipments. And the reason of causing the vibration of machines is given.