考虑叶片弹性效应及轴系振动的舰船螺旋桨轴承力特性研究

The propeller bearing force will excite the coupling vibration of the blade-shaft-hull, which radiates specific low frequency noise. This kind of low-frequency noise is easily detected by enemy’s sonar because of its obvious characteristics of line spectrum and narrow band spectrum, and it has become a key issue for further improvements of the noise stealth performance of warships. Therefore, the study on the characteristics of propeller bearing force is helpful for revealing the cause of the spectrum structure of such low-frequency noise and then controlling it, which has important military significance. At present, there is little analysis on the influence of blade elastic effect and shafting vibration on propeller bearing force. However, these have important effect on bearing force from our vibration testing results against several warships in service and some warship data from Russia. In view of this, this project intends to carry out relevant research work. Firstly, the new calculation model of propeller bearing force is established with consideration of the coupling of nonuniform flow, shafting vibration and blade elastic effect, using the boundary element method coupled with finite element method. Secondly, the influence of the blade elastic effect and the shaft vibration on propeller bearing force is revealed. At last, the research results are verified by experiments that are conducted on a large-scale experimental platform with propeller-shaft system in gravity-type water tunnel. This project could provide guidelines for further clarifying the causes of low-frequency noise caused by the propeller bearing force and offer references for propeller optimum design.

螺旋桨轴承力激起桨-轴系-艇体耦合振动产生的低频噪声，由于其中的线谱和窄带谱结构特征明显，极易被敌方声呐探测，目前已成为制约舰船声隐身性能进一步提升的关键问题。因此，针对螺旋桨轴承力的特性研究，有助于揭示这类低频噪声中的线谱和窄带谱成因并加以控制，具有重要军事意义。而现有国内外研究均极少考虑桨叶弹性及轴系振动等因素对轴承力的作用。根据项目申请者对数艘在役舰船的现场测试结果及相关引俄舰船资料，这些因素对螺旋桨轴承力有极其重要的影响。鉴于此，本项目开展相关研究。首先考虑流体、弹性桨及轴系间的耦合关系，利用边界元法耦合有限元法，构建不均匀来流、轴系振动及桨叶弹性等多因素作用的螺旋桨轴承力计算新模型；其次研究并揭示叶片弹性效应及轴系振动等因素对螺旋桨轴承力特性的影响规律；最后在水洞桨-轴系统实验平台上设计并完成实验研究。本项目研究有助于阐明舰船低频噪声中线谱及窄带谱的成因，并指导螺旋桨的优化设计。

声隐身性能是衡量舰船性能的一项重要指标。然而，螺旋桨轴承力引起的噪声中，线谱和窄带谱结构特征明显，极易被敌方声呐探测，目前已成为制约我国舰船声隐身性能进一步提升的关键问题。因此，针对螺旋桨轴承力特性研究，有助于揭示这类低频噪声成因。本项目计及不均匀流场、桨叶弹性、轴系振动等复杂耦合因素的影响，系统深入的研究了螺旋桨轴承力特性。利用有限元法耦合边界元法建立了不均匀来流、轴系振动及桨叶弹性等多因素作用的螺旋桨轴承力计算新模型，研究了叶片弹性效应及轴系振动等因素对螺旋桨轴承力特性的影响规律，阐明了舰船低频噪声中线谱和窄带谱结构特征的成因，揭示了不均匀流场引起的激励力与轴系振动引起的激励力间的幅值和相位关系。相关研究结果在重力式水洞实验平台上得到实验验证。本项目成果可为桨-轴系-艇体耦合系统振动响应计算提供准确的输入载荷，可指导设计出具有低轴承力、高效率的螺旋桨，具有重要的军事战略意义。