The Single-disc Cantilever Rotor Transient Dynamic Balancing Method And Its Influencing Factors

Nowadays, with creasing power, speed and slender shaft of rotating machines, the balancing problem of rotor becomes more and more importance. We always meet some troubles in balancing at-site when using dynamic balance method. Therefore, a proper balance method, which needs less test runs, has highly efficiency, time saving and low cost, need to be deeply investigated and applied in practice.The purpose of this dissertation is to put forward of a method for transient balancing rotor conveniently and quickly. It can recognize imbalanced amount of rotor from the vibrational information. Firstly, based on the Matlab software package and a transfer matrix approach, critical speeds and imbalance dynamic responses (put in keyphasor signal) of the cantilever rotor with one disc are calculated. Then by analyzing and studying the transient response of flexible rotor with one disc, the following basic dynamic phenomena have been found after the rotor past critical speed: Ⅰ.The amplitude, phases and precession speed of flexible rotor appear fluctuation regularly, and disappear gradually along with rotate speed increased;2.A11 of them have the same frequency, which crescent to a stable value step by step;3. In the high rotational speed area, which is far away from the critical speed, the phase angle doesn't increase any more, and fluctuates around some fixed value which equals (2n + l)π rad (here n is a natural number);4. Advancing angular velocity can be divided into three parts, in the second of which the included angle γ between center of mass and keyphasor signal equals γ-at₁² /2-at₀²/2-ψ₁ , in the third of which the included angle γ-at₁² /2-at₀²/2-ψ₁±π;According to these special regular pattern and phenomenon, a new method of transient balancing flexible rotors with one disc, which just needs two accelerating processes, is proposed. It can recognize imbalanced amount of the rotor from amplitude, phases and precession speed at the first one. It can acquire the magnitude of the unbalance by adding trial mass at the second one. Then the accommodation of the balanced method is attained from putting in the disturbance. At last, this balance method is verified through experimentation. The fact that the results of calculation and experimentation are accordant proves that the balancing method in this paper is practical and effective.