航天器直接声场试验技术研究进展

为了使得航天器的设计、制造与试验能够并行开展,同时降低试验成本、缩短试验周期,在最近十余年,国外发展了直接声场试验技术(DFAT)。这种新型的噪声试验技术与混响场试验相比更为方便、快捷,极大地提高了试验效率。针对未来飞行器研制与试验,论述了DFAT技术的进展情况。从扬声器阵列的布置方式、控制技术的改进和DFAT技术目前所具备的能力现状等三个方面阐述了DFAT试验系统的组成与发展,对近十年来国外开展的典型DFAT试验进行了梳理,并总结了在试验中发现的声场一致性、与混响场的差异、试验件结构响应和驻波等相关问题。对DFAT技术的后续应用前景进行了展望,提出了我国发展DFAT技术所面临的问题和挑战。

电驱可控震源永磁同步电机气动噪声特性分析

为分析电驱可控震源永磁同步电机在不同运行工况下的气动噪声特性,采用了定常SST_(к-ω)湍流模型,建立了永磁同步电机仿真模型,开展了永磁同步电动机的气动噪声流场分析,锁定了永磁同步电机离心风扇与导风罩部位为电机最主要的气动噪声源区域。基于声类比法(FW-H)耦合非定常流场计算了永磁同步电机气动噪声声场特性,开展了永磁同步电机声场试验,结果表明:离心风扇表面声功率级峰值达到166 dB,为永磁同步电动机的主要噪声源;离心风扇远场气动噪声具有明显的指向性并沿着轴向方向进行传播,噪声的主要能量集中在频率225~2500 Hz;试验与仿真结果在不同测点处声压级基本一致,验证了仿真模型与结果的准确性。

Research on vibration and near-field sound radiation of ring-ribbed cylindrical shell coated deadening and decoupling materials

The research on structural vibration and sound radiation of underwater ring-ribbed cylindrical shell, which is coated with a kind of deadening and decoupling materials, becomes a focus in recent years. This paper analyzes the problem on two aspects: model experiment and numerical calculation. The model experiment is carried out including three cases firstly, in which the structural vibration response and radiating acoustic field are measured respectively, and the results gained in these three cases are analyzed to discuss the effect of reducing structural vibration and radiating noise of the deadening and decoupling materials. The coupling FEM/BEM and the SEA methods are both used in numerical calculation, i.e. the arithmetic of the coupling FEM/BEM method is adopted to calculate the low frequency characteristics and the SEA method is adopted to calculate the medium-high frequencies characteristics of the model. By comparing experimental results with numerical calculation results, it is proved that the algorithm adopted in this paper is reasonable.