采用多体动力学方法进行汽轮机机械振动激励源精确分析,在激励源分析结果的基础上研究低频激励下的机组振动响应,并采用声传递向量(Acoustic Transfer Vector,ATV)方法研究汽轮机组表面与外场辐射的声压传递贡献量,从多体动力学的角度并结合流固耦合的方法综合分析汽轮机组振动噪声产生机理并研究噪声典型传递路径.研究结果表明,旋转激励源为汽轮机组的主要振动激励源,在低频段汽轮机组辐射模式为单极子,在中高频段汽轮机组辐射模式为偶极子.由噪声辐射的指向性极坐标图可知,在不同高度处噪声指向性相似,并都在长度方向上取得噪声声压级较大值,具有较强的指向性.计算方法对汽轮机组减振降噪研究具有一定的指导意义.
Vibration and Sound Radiation Mechanism and Transmission Path of Steam Turbines Based on Multibody Dynamics
The multibody dynamics method is used to accurately analyze the excitation sources of steam turbine mechanical vibration.Based on the analysis results of the excitation sources,the vibration response of the unit under low-frequency excitation is studied,and the Acoustic Transfer Vector(ATV)method is used to study the contribution of sound pressure transmission between the surface and external field radiation of the steam turbine unit.From the perspective of multibody dynamics and the method of fluid structure coupling,the mechanism of vibration and noise generation of the steam turbine unit is comprehensively analyzed,and the typical transmission path of noise is studied.The research results indicate that the rotating excitation source is the main vibration excitation source for the steam turbine unit,the radiation mode of the steam turbine unit in the low frequency range is monopole,and the radiation mode of the steam turbine unit in the medium and high frequency range is dipole.From the directional polar plot of noise radiation,it can be seen that the noise directionality is similar at different heights,and larger values of noise sound pressure levels are obtained in the length direction,indicating strong directionality.The calculation method is of certain guiding significance for the study of vibration and noise reduction of steam turbine units.
steam turbine unitvibration and sound radiationtransmission pathmultibody dynamicsvibration and noise reduction
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