Unbalance Response Analysis of Sliding Bearing and Rotor System in Multi Axis Compression Device
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摘要:
从转子动力学角度出发,结合达朗贝尔原理和传递矩阵法建立了转子离散化动力学方程,基于流体动压轴承理论和有限差分法计算非线性油膜压力,提出了一种由滑动轴承支承的多轴离心压缩机转子系统动力学模型,并从轴心轨迹、轴承偏心率和频谱响应等方面分析了该非线性轴承−转子系统的不平衡效应及振动特征。结果表明,转子在理想化的不平衡量下,振动特征主要表现为次同步涡动。随着不平衡量的增加,转子主同步响应增大,在0.2 g·mm不平衡量下,转子系统出现多重椭圆轨迹,非常不利于转子系统的使用寿命。在G1平衡精度下,转子系统具有良好的动力学特性,可保证多轴压缩机主轴转子系统在正常工况下稳定健康运转。
Abstract:From perspective of rotor dynamics, a discretized dynamic equation for rotor was established by combining the D'Alembert principle and transfer matrix method.Based on theory of hydrodynamic bearings and finite difference method for calculating nonlinear oil film pressure, a dynamic model of multi axis centrifugal compression device rotor system supported by sliding bearings was proposed.The imbalance effect and vibration characteristics of nonlinear bearing rotor system were analyzed from aspects of axis trajectory, bearing eccentricity, and spectral response.Results indicated that vibration characteristics of rotor under idealized imbalance were mainly manifested as subsynchronous vortices.As imbalance increased, main synchronous response of rotor increased.Under an imbalance of 0.2 g·mm, rotor system exhibited multiple elliptical trajectories, which was very detrimental to service life of rotor system.Under G1 balance accuracy, rotor system had good dynamic characteristics, which could ensure stable and healthy operation of multi axis compression device spindle rotor system under normal working conditions.
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表 1 多轴离心压缩机转子系统结构参数
Table 1. Rotor system structure parameters of multi-axis centrifugal compressor
参数 数值 质量/kg M1=56.24,M2=M4=14.40,M3=39.00,M5=76.38 轴段长度/mm l1=310,l2=l3=225,l4=321 轴段直径/mm d1= d6=115,d2= d3= d4= d5=95 极转动惯量/(10−3 kg·m−2) Jρ1=805,Jρ2= Jρ4=21,Jρ3=66,Jρ5=1384 直径转动惯量/(10−3 kg·m−2) Jd1=518,Jd2= Jd4=14,Jd3=40,Jd5=874 杨氏模量/GPa E=206 临界转速/(r·min−1) 一阶临界转速4800;二阶临界转
速36398表 2 滑动轴承结构参数
Table 2. Structure parameters of plain bearing
参数 数值 润滑油黏度μ/(10−3 Pa·s) 46 轴承温度/ °C 进油温度40,出油温度63 轴承内径r/mm 95 轴承宽度L/mm 70 轴承间隙c/mm 0.09 单瓦块角度θ1/(°) 58 表 3 滑动轴承油膜压力计算结果
Table 3. Calculation results of oil film pressure of sliding bearing
参数 瓦块1 瓦块2 瓦块3 瓦块4 瓦块5 1 #滑动轴承 最小油膜厚度/mm 0.102 0.110 0.091 0.070 0.077 最大油膜压力/MPa 2.882 2.425 3.665 6.268 5.190 2 #滑动轴承 最小油膜厚度/mm 0.102 0.108 0.089 0.071 0.079 最大油膜压力/MPa 2.853 2.528 3.821 6.096 4.868 -
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