低噪环形螺旋桨新参数化方法设计及其水动力噪声研究

Design of a new parametric method for low-noise toroidal propeller and its hydrodynamic noise study

  • 摘要:
    目的 环形螺旋桨旋转形成的涡流分布于整个叶片,有效防止梢涡泄出,使漩涡在水中能快速消散,减少水动力噪声传播,然而,环形螺旋桨结构比较复杂,使用常规螺旋桨的建模方法难以对环形螺旋桨进行建模,因此需要研究环形螺旋桨的参数化建模方程。
    方法 引入螺旋桨轴距的概念,将环形螺旋桨的数学建模方程表示为随轴距变化的函数关系。定义与环形螺旋桨坐标系xy平面夹角度为α的基准面,确保环形螺旋桨的参考线位于与旋转轴成α的基准面上,以该参考线为基准,基于类−形函数转换法(CST)构建沿参考线分布的NACA翼型,形成三叶环形螺旋桨模型。进一步引入FW-H声类比方程,对比环形螺旋桨和DTMB P4119螺旋桨的流场和非空化噪声。
    结果 试验结果表明,相同推力条件下,环形螺旋桨的降噪效果显著优于DTMB P4119螺旋桨:在径向平面一定半径的圆周上,其各测点总噪声声压级比DTMB P4119螺旋桨降低约4 dB;在轴向平面一定半径的圆周上,各测点总噪声声压级比DTMB P4119螺旋桨降低4~6 dB。
    结论 所提方法可为环形螺旋桨设计提供参考,全面分析与评估噪声水平,可为船舶和水下航行器等装备的水动力噪声抑制提供理论借鉴依据,同时为降低水下航行器和船舶的螺旋桨水动力噪声提供技术支撑。

     

    Abstract:
    Objectives The vortex formed by the rotation of the toroidal propeller will be distributed to the entire blade, effectively preventing the tip vortex leakage, so that the vortex can be quickly dissipated in the water, reducing the propagation of hydrodynamic noise. However, due to its complex structure, it is difficult to model the toroidal propeller using conventional propeller modelling methods, so the parametric modelling equations of the annular propeller need to be studied.
    Methods The concept of propeller wheelbase is introduced to express the mathematical modelling equations of a toroidal propeller as a functional relationship that varies with wheelbase. A reference plane with the degree of angle α to the xy-plane of the toroidal propeller coordinate system is defined to ensure that the reference line of the toroidal propeller is on the reference plane that is α to the axis of rotation, and the parameters of the toroidal propeller are taken as the reference line, and the NACA airfoils distributed along the reference line are constructed based on the Class-Shape Function Transformation (CST) method to form a three-bladed toroidal propeller model. Further, the FW-H acoustic analogue equation is introduced to compare the flow field and non-cavitation noise between the toroidal propeller and the DTMB P4119 propeller.
    Results It is found from the experimental results that under the same thrust condition, the toroidal propeller shows a great advantage in noise reduction, with the total noise sound pressure level at each measurement point on the circumference of a certain radius of the radial plane reduced by about 4 dB compared with that of the DTMB P4119 propeller, and that the total noise sound pressure level at each measurement point on the circumference of a certain radius of the axial plane is reduced by about 4~6 dB compared with that of the DTMB P4119 propeller.
    Conclusions The proposed method can provide reference for the design of toroidal propellers, and the comprehensive analysis and evaluation of the noise level can provide a theoretical reference basis for the suppression of hydrodynamic noise of ships, underwater vehicles and other equipment, and at the same time provide technical support for the reduction of hydrodynamic noise of propellers of underwater vehicles and ships.

     

/

返回文章
返回