变阻尼“O”型圈支承柔性转子动力学试验研究

Experimental research on flexible rotor dynamics with different “O” ring dampings

建立由动静压混合气体轴承支承的10 kg单跨柔性转子试验平台以开展不同阻尼"O"型圈支承下气体轴承-转子系统动力学特性试验研究。基于该试验台,进行了相同气体轴承供气压力下,丁腈,氟胶,硅胶三种不同阻尼材料"O"型圈支承轴系的动力学特性试验。试验中轴系经过平动临界、锥动临界、一阶弯曲临界三阶临界转速,在前两阶临界处轴系振动幅值基本相同,在一阶弯曲临界转速处振幅增加,升速率降低。转速大于一阶弯曲临界转速时,丁腈、氟胶"O"型圈支承轴系出现低频振荡,振动幅值增加现象。试验表明:提高"O"型圈支承阻尼,如采用丁腈"O"型圈,可以提高一阶弯曲临界转速轴系稳定性,但会造成度过一阶弯曲临界转速后低频振荡出现转速提前,低频幅值增加,加大转子失稳风险。

A 10 kg flexible rotor supported by gas bearing test rig was established to conduct the dynamic characteristics experiments with different damping coefficients of“O”rings.The dynamic characteristics of the rotor bearing system with acrylonitrile-butadiene“O”rings,fluorine rubber“O”rings,and silicon rubber“O”rings was researched based on the test rig under the same bearing supply pressure,respectively.Translational critical speed,cone dynamic critical speed,and the first bending critical speed were below the maximum operating speed of the rotor.Vibration amplitudes of the first two critical speeds were similar.The amplitude of working frequency was large and the rotating speed increasing rate decreased at the first bending critical speed.With acrylonitrile-butadiene“O”rings and fluorine rubber“O”rings,the gas film oscillation occurred when the rotating speed was larger than the first bending critical speed and the amplitude increased.It can be concluded from experiments that the dynamic stability of first bending critical speed improved with O-ring damping.However,the low frequency oscillation is more easily to occur and the vibration amplitude increases after the gas whip with larger damping O rings,which is dangerous to the safety of the system.