为分析某船首侧推振动强烈原因,采用正负螺距交替增加方案,在锚泊状态下测量首侧推的振动数据.振动速度随着螺距角的增加而变大,当螺距小于70％时,振动速度在桨叶叶频处幅值最大,随着螺距继续增加,振动速度幅值转移至低于叶频区域.首侧推桨叶进流均匀度与桨叶空泡是引起振动的主要原因.因首侧推导臂增加了桨叶负螺距时进流的不均匀度,造成负螺距时振动强度大于正螺距；数值模拟结果显示,70％螺距时,桨叶叶梢区域存在明显空泡,随着螺距的增加,空泡逐渐向叶背区域扩展.根据振动测试分析结果,新设计船舶应优化设计进流条件,增加进流的均匀度.适当选取额定推力较大的侧推型号,以减小电机最大功率的桨叶螺距,降低空泡激励的振动.%In order to analyze the serious vibration problem of ship bow thruster,the vibration data is measured when the ship is anchored in anchorage ground.The propeller pitch is alternant added during the test.The test results show that the vibration level of bow thruster is increased with propeller pitch and the vibration magnitude is biggest at blade passing frequency when the pitch is lower than seventy percent.However,the vibration biggest magnitudes are transferd to other frequencies which are lower than blade passing frequency when the pitch is larger than seventy percent.The propeller inflow uniformity and cavitation are mainly take charger for the vibration.The inflow is more nonuniformity when the blades are adjusted to negative pitch and vibration level is more serious.Numerical results show the cavitation is just developed at blade tip region at seventy pitch,while the cavitation region is expanded to blade back region when the pitch is added.For the new designed similar ship,the inflow uniformity could be added by improving the inflow condition according to hull shape.A larger bow thruster is more suitable for the new ship,as the pitch is reduced and cavitaiton is restricted at maximum pitch.
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