船舶推进轴系瞬时转速的测试与分析

Testing and analysis of instantaneous rotating speed on ship propulsion shaft

瞬时转速作为柴油机缸内燃烧状态的监测参数一直受到重视,但对船舶推进轴系瞬时转速的诊断应用研究目前还不多。为了解船舶推进轴系不同部位瞬时转速的波动特征,分别在自动化机舱实验室和远洋实习船上对柴油主机飞轮端、水力测功器轴段和船舶尾轴段的瞬时转速进行测试与分析,证实了船舶主机飞轮端的瞬时转速受螺旋桨的影响较小,可以反映柴油主机各缸内的燃烧状态,也验证了尾轴段的瞬时转速可以反映螺旋桨的工作状态。可以利用船舶尾轴段瞬时转速的转速波动特性和频率特性判断螺旋桨的工作状态,为利用推进轴系的瞬时转速进行船舶推进装置的状态监测和故障诊断奠定了基础。

To study the behavior of instantaneous rotating speed on different parts of propulsion shaft, experiments were carried out in engine room laboratory and onboard ship respectively for the testing and analysis of instantaneous rotating speeds on main diesel engine flywheel, hydraulic dynamometer shaft and ship propulsion tail shaft. It was proved that propulsor had little influence on the instantaneous rotating speed on main engine flywheel, which could be used to monitor the combustion condition of main diesel engine inside cylinder combustion chambers. It was also discovered that the instantaneous rotating speed on ship propulsion tail shaft could reflect the working condition of propulsor and had little affect from the main engine, especially when ship propulsion shaft is long enough or when some a flexible coupling is installed on the shaft. These conclusions make it possible for the condition monitoring and fault diagnosis of ship propulsion devices with the instantaneous rotating speeds on different parts along the propulsion shaft.