气流激振对球轴承涡轮增压器转子动力学特性的影响

摘要

The gas excitation force of a vehicular turbocharger rotor-ball bearing system consists of sealing fluid excitation force and tip clearance gas excitation one.Here,sealing fluid excitation force and tip clearance gas excitation one of a certain vehicular turbocharger were calculated with Black model and Alford model.The dynamic model of the turbocharger rotor-ball bearing system was simulated with the above calculation results so that the influence of sealing fluid excitation force and tip clearance gas excitation one on critical speed,stability and unbalanced response of the rotor system could be caculated.Furthermore,the simulation results were compared with those of the critical speed tests of the system, the model without tip clearance gas excitation force solely and the model without both sealing fluid excitation force and tip clearance gas excitation one.The study results showed that the sealing fluid excitation force increase the system damping decreases the amplitude of the system responses and improves the stability of the turbocharger rotor-ball bearing system;gas excitation increases the cross-coupled stiffness of the system and decreases the amplitude of the steady response of the system.%车用球轴承涡轮增压器气流激振力包括密封流体激振力和叶顶间隙气流激振力。针对某型号车用球轴承涡轮增压器，分别应用Black模型和Alford模型，计算得到密封流体激振力和叶顶间隙气流激振力。将计算结果代入模型进行仿真计算，得到密封流体激振力和叶顶间隙气流激振力对增压器转子系统临界转速、稳定性、不平衡响应的影响规律。分别与临界转速实验结果、与未添加叶顶间隙气流激振力模型计算结果、未添加密封流体激振力和叶顶间隙气流激振力的计算结果进行对比分析，结果表明：密封流体激振力增加系统阻尼，降低球轴承涡轮增压器转子系统的振幅，提升系统的稳定性；气流激振增加系统交叉刚度，降低系统稳态响应振幅。