Analysis Of Dynamic Characteristics Of Distributed Rod Rotor-bearing Systerm

As a kind of power output device，it is about1940s that gas turbines boarded thestage of history. After nearly eighties years of development, gas turbine has become themost popular mechanical for the energy utilization equipment. And it is called the Pearlon the crown of mechanical industry. Distributed rod-fastened rotor is light and highstrength so it is the most common rotor style of the Heavy duty gas turbine. The biggestdifference of the distributed rod-fastened rotor and the traditional rotors is the contactstiffness of the distributed rod-fastened rotors. Equivalent bending stiffness of the rotorcan have a great influence on the dynamic characteristics of the rotors.First of all, rough surfaces of the discs of the distributed rod-fastened rotors will beanalyzed. And then, contact model based on Persson contact theory will be built forcalculated the contact stiffness of the discs of the rotors. Besides, axial stiffness and theequivalent bending stiffness equation is also solved. The relationship between thebending stiffness with the preload and the wheel angle will also be presented.And then, the dynamic model of the rotor is established according to the actualmodel of the rod-fastened rotor. Nature frequency will be obtained using Riccati transfermatrix method based on rigid support conditions. Besides the formulation of theassembled rotor-plain journal bearing system and rotor-tilting pad journal bearingsystem are established and the dynamic characteristics are analyzed. Variation of rotor’snature frequency of rotor-bearing system with the bending stiffness and pre-tighteningforce are solved. And the nature frequency of the rotor-bearing system are also solved.The difference of integral rotor with disturbed rotor in nature frequency and vibrationmode is shown.What’s more, the unbalanced response will be obtained using Riccati transfermatrix method based on rigid support conditions. And How preload affect theunbalanced response of the rotor is exposed in this essay. And the unbalanced responseof the rotor-bearing system are also solved. What’s the difference betweenrigid-supporting and bearing-supporting are compared. To added, How preload affectthe unbalanced response of the rotor-bearing system is exposed. And the tendency of thenature frequency and the vibration amplitude of the rotor with different pre-tightening load are also given.