泡沫铝材料声学参数计算及其应用

Calculation of Acoustic Parameters of Aluminum Foam and its Application

泡沫铝材料曲折因子、热特征长度和黏性特征长度等声学参数对其吸声性能有重要影响。针对泡沫铝声学参数难以在实验室完成检测的问题,本文研究采用Johnson-Champoux-Allard多孔介质模型,运用全局最小二乘优化方法完成对泡沫铝材料的声学参数反求,通过与熔体发泡法制备的泡沫铝吸声性能实测值比较,验证所提方法的可行性;通过数值计算,进一步分析泡沫铝流阻率、黏性特征长度、热特征长度、曲折因子和孔隙率等声学参数与其吸声系数的关系。结果表明:增大流阻率、曲折因子和孔隙率均使泡沫铝吸声性能增强;热特征长度和黏性特征长度的改变对吸声系数影响较小;增大孔隙率,泡沫铝的吸声性能提升最为明显。研究成果可为泡沫铝的研发制备和实际工程应用提供借鉴和指导。

Acoustic parameters of aluminum foam,such as tortuosity factor,thermal characteristic length and viscous characteristic length,have important effects on its sound absorption ability.To solve the problem that the acoustic parameters of aluminum foam are difficult to be measured in the laboratory,this paper studies the use of Johnson-Champoux-Allard porous medium model and global least squares optimization method to complete the reverse calculation of acoustic parameters of aluminum foams.By mutual comparing of the measured values of sound absorption performance of aluminum foams prepared by melt foaming method,the feasibility of the proposed method was verified.The effects of acoustic parameters such as airflow resistivity,viscous characteristic length,thermal characteristic length,tortuosity factor and porosity on the sound absorption performance of the aluminum foam were further explored through numerical calculations.The results show that the sound absorption performance of the aluminum foam increases with the increase of airflow resistivity,tortuosity factor and porosity;the change of thermal characteristic length and viscous characteristic length has little effect on the sound absorption coefficient;and with the increase of porosity,the sound absorption performance of aluminum foam is most significantly improved.This work has provided a reference and guidance for the development,preparation and practical engineering application of aluminum foams.