多缸大功率船舶主机在一缸熄火后继续工作,将偏离设计工况,工作性能参数将发生较大变化.通过构建多体动力学计算模型,对比分析船舶主机在额定工况与一缸熄火工况下的主轴承润滑状况.在4#缸熄火状况下,其两侧主轴承MB4与MB5在其正常发火时刻,即曲轴转角188°附近载荷变化较大,由下瓦受力变成了上瓦受力;此时两轴承油膜压力分布也随之发生变化,高油压区分布于上瓦;轴承间隙高度与油膜压力相对应地变化;两轴承轴心运动轨迹出现明显改变,皆有剧烈的离心和向心运动,若长时间运行,轴承有发生穴蚀破坏的危险.%Multi-cylinder marine main engine will leave designing condition if it continues work while one cylinder misfires,and its performance parameters will change greatly. The model of multi-body dynamic slide bearing lubrication was established to analyze the state of main bearings lubrication under the condition of the rated and one cylinder misfiring. The main bearing load of MB4 and MB5 changes greatly at about 188° of crank angle while No. 4 cylinder misfires and No. 4cylinder is in normal firing angle. The oil film pressure distribution of two bearings changes and the high oil pressure zone locates at the upper shell. The orbit paths of two bearings change clearly and have both centrifugal motion and centripetal motion. Beating may be in the danger of cavitations for running in a long time.
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