考虑运行参数耦合作用的舰船轴系动力学特性研究

Dynamics of Ship's Shaft System Considering Coupling Effect of Operating Parameters

关键词:  舰船轴系  轴承油膜  螺旋桨激振力  中间变量法  动力学特性

Key words:  Marine shaft system  Bearing oil film  Propeller exciting force  Intermediate variable method  Kinetic characteristics

摘要:

为分析清楚多动态因素作用下的轴系动力学特性，以保障轴系运行的可靠性和安全性，以某桨-轴-壳体为对象，建立其有限元模型，基于有限差分法和小扰动法求解各轴承油膜压力分布和油膜刚度，基于来流法求解艉部伴流场影响下的螺旋桨激振力。在此基础上，提出中间变量法，以转速为中间变量，在系统分析转速对油膜压力分布和螺旋桨激振力变化影响的基础上，研究得到转速变化下轴系整体动力学特性规律。研究结果表明：转速的增加使相邻轴承载荷差值分别降低了13398N和11102N，改善了轴系的载荷分布状态；轴系振动响应中的共振峰值受特定转速影响较大，在53.333Hz的轴向共振频率处以及14.667Hz，26Hz的横向共振频率处，轴系各参考点共振峰值的最大值出现在190r/min运行工况下。

Abstract:

In order to analyze the dynamic characteristics of the shaft system under the action of multiple dynamic factors to ensure the reliability and safety of the shaft system operation， a finite element model of the propeller-shaft-shell is established， and the oil film pressure distribution and oil film stiffness of each bearing are solved based on the finite difference method and the small perturbation method， and the propeller excitation force under the influence of stern companion flow field is solved based on the inflow method. On the basis of the above research content， the intermediate variable method with the rotational speed as the intermediate variable is proposed， and the overall dynamic characteristic law of marine shaft system under the change of rotational speed is studied based on the systematic analysis of the effect of rotational speed on the oil film pressure distribution and the change of propeller excitation force. The results show that the increase of rotational speed reduces the load difference of adjacent bearings by 13398N and 11102N respectively， which improves the load distribution of the shaft system. The resonance peak in the vibration response of the shaft system is influenced by the specific rotational speed.The maximum value of the resonance peaks at each reference point of the shaft system occurs at the operating condition of 190r/min at the axial resonance frequency of 53.333Hz and at the horizontal resonance frequencies of 14.667Hz and 26Hz.