航空燃油齿轮泵滑动轴承非线性瞬态性能数值分析

Numerical Analysis of Non-Linear Transient Characteristics of Aviation Fuel Gear Pump Sliding Bearings

为研究航空燃油齿轮泵滑动轴承在复杂交变载荷扰动下的瞬态润滑行为,建立了燃油齿轮泵滑动轴承的瞬态计算模型,该模型考虑了滑动轴承油膜空化边界的质量守恒和其所处非线性动态承载环境的影响。在此基础上使用批处理技术实现了燃油齿轮泵和滑动轴承的联合仿真计算,在滑动轴承的瞬态润滑计算过程中计入了燃油泵瞬态内流场和其动态载荷的耦合作用。以此进行轴心轨迹稳定性分析以及轴承瞬态润滑性能分析研究。研究结果表明:滑动轴承计算模型的计算结果与实验数据较为吻合,误差保持在1.2%以内;燃油齿轮泵的动态载荷对轴心轨迹的影响体现在轨迹未稳定段偏移的增大以及静平衡位置的消失;通过不同关键参数的对比研究发现:合理的增大宽径比或减小间隙比可以获得更为理想的轴心轨迹静平衡位置。间隙比由0.2%增至0.6%时,未稳定阶段轴心位置的变化趋势由双峰变为单峰,速度稳定段曲线的波动幅值先增大后趋于不变;当宽径比由0.6增至1.2时,全周期内速度响应曲线的偏移降低;在轴承瞬态润滑特性中,轴承载荷变化对于泄漏流量具有较强的敏感性,而对最小油膜厚度的敏感性较差。

In order to study the transient lubrication behavior of sliding bearings inside aviation fuel gear pump under complex alternating load disturbance,a transient calculation model was established.The model took into account the mass conservation of the oil film cavitation boundary and the influence of the non-linear dynamic load-bearing environment.The combined simulation calculation of fuel gear pump and bearing was realized by batch processing technology,while the effect of transient internal flow field and dynamic load given by fuel pump was considered in the transient calculation process.On this basis,the axis center trajectory stability analysis and transient lubrication performance analysis were carried out.The results show that the error between the calculated results of the bearing model and the experimental data is less than 1.2%.The influence of dynamic load generated by fuel gear pump on bearing axis trajectory is reflected in the increase of trajectory unstable stage offset and the disappearance of static balance position.Comparative studies predict that the equilibrium position is superior for a bearing with higher width-diameter ratio or smaller clearance ratio.When the clearance ratio increases from 0.2%to 0.6%,the change trend of the axis position in the unstable stage changes from double peak to single peak,and the fluctuation amplitude of the curve in the velocity stable section increases first and then tends to remain unchanged.When the aspect ratio increases from 0.6 to 1.2,the deviation of the velocity response curve decreases in full cycle.In the transient lubrication characteristics of bearings,the sensitivity of the leakage flow rate to bearing load variation is strong,while the minimum oil film thickness is poor.