裂纹对浮环支承涡轮增压器转子系统动力特性影响研究

Study of Crack Effect on Dynamic Characteristics of Turbocharger Rotor Supported by Floating Rings

为研究裂纹对涡轮增压器转子系统动力学特性的影响，建立了含开闭裂纹的浮环支承涡轮增压器转子系统动力学模型。数值仿真结果表明，转速比约小于0．5时，开闭裂纹抑制系统的内油膜失稳，使系统作幅值较大的单周期运动，且使一倍频幅值增大；转速继续增大时系统在裂纹作用下出现分频振动频谱，系统产生倍周期、拟周期及混沌等复杂振动特性。转子系统在转速比约为0．5～1．5时无法作稳定单周期运动。裂纹深度越大，对系统动力学特性影响越大。

In order to study the effect of crack on the dynamic characteristics of a turbocharger rotor, the dynamic model of the turbocharger rotor with a switching crack supported by floating rings was established. The results of numerical simulation show that, when the speed ratio is less than 0.5, the inner oil-film instability is suppressed, a single periodic motion occurs in the system and the amplitude of one octave is increased with the switching crack. With the increase of speed, fractional frequency spectrum appears because of the crack, which leads to the complicated vibration characteristics such as periodic, double-periodic and quasi-periodic motion. When the speed ratio is between 0.5 and 1.5, the single periodic motion disappears. The deeper the crack depth is, the greater impact the crack has on dynamic characteristics of the system.