基于面元-涡粒子法的螺旋桨气动特性及噪声研究

Research on aerodynamics and aeroacoustics of propeller based on panel⁃vortex particle method

为了满足叶轮机械的高效非定常气动仿真需求,发展了耦合面元-涡粒子法和Lowson自由远场声学模型的气动声学快速方法,并应用于某型螺旋桨气动特性和噪声特性的预测研究。气动计算结果表明:与有限体积法(finite volume method,FVM)相比,使用面元-涡粒子法(panel⁃vortex particle method,PVM)可以获得一致的叶表压力分布、下游尾迹速度分布和推力;相比于二阶的有限体积法,面元-涡粒子法的尾迹涡量数值耗散更低,尾涡附近速度梯度变化更明显。声学计算结果表明:与有限体积法结合Lowson模型的声学结果相比,使用面元-涡粒子法与Lowson模型结合可以解出相近的声压级指向性结果,在声场特征指向位置处(桨盘前轴向夹角60°位置)1BPF(blade passing frequency)下声压级幅值相对误差仅为5%,能满足声学分析需求。在计算耗时方面,面元-涡粒子法求解速度比有限体积法高出一个量级,证实发展的方法能满足分布式电推进系统动力叶轮机械的非定常气动特性和噪声性能的高效预测评估。

The highly⁃efficient and unsteady aerodynamic simulation of turbomachinery is urgently required.The panel⁃vortex particle method is coupled with a far free field sound model established with the Lowson method and aims to fast predict aerodynamic and acoustic properties.The aerodynamic results show that,compared with the aer⁃odynamic results acquired with the finite volume method,the use of the panel⁃vortex particle method may obtain appropriate pressure distribution and velocity distribution in the downstream region of a propeller and that the overall thrust prediction is accurate enough.The vortex distribution features show that the panel⁃vortex particle method has less numerical diffusion.Therefore,the velocity gradient is more accurate near the wake vortex.Com⁃pared with the sound pressure level acquired with the finite volume method,the sound pressure level simulated with the panel⁃vortex particle method has the same directivity pattern.The relative error of sound pressure in the 60°for⁃ward direction is 5%under 1BPF(blade passing frequency),which satisfies acoustic analysis requirements.As for time consumption,the use of the panel⁃vortex particle method consumes 10%of time when the finite volume method is used,proving that the panel⁃vortex particle method coupled with the Lowson method can satisfy the design and application needs of unsteady aerodynamic and aeroacoustic noise of a distributed electric propulsion system.