添加羰基铁粉的聚氨酯泡沫特征参数辨识及低频吸声性能研究

Study on characteristic parameters identification and low frequency sound absorption performance of polyurethane foam filled with carbonyl iron particles

探究羰基铁粉添加和聚醚多元醇与异氰酸酯不同比例对聚氨酯泡沫的物理特征参数和低频吸声性能的影响,旨在改善传统聚氨酯泡沫的低频吸声效果.首先基于JCA(Johnson-Champoux-Allard)模型,采用最小二乘法估算磁性聚氨酯泡沫的物理特征参数(流阻率、孔隙率、曲折率、黏性特征长度、热性特征长度),同时基于传递函数法,利用双通道阻抗管,测量聚氨酯/磁性聚氨酯泡沫在64~1600 Hz的吸声性能.结果表明,相同比例聚醚多元醇与异氰酸酯的聚氨酯/磁性聚氨酯泡沫,羰基铁粉的加入会明显改变聚氨酯泡沫的特征参数,其中流阻率和孔隙率均增加,增加范围分别为82.9%~211.3%和0.8%~5.3%,曲折率降低范围为32.7%~74.5%,黏性特征长度降低范围为81.4%~94.0%,但热性特征长度无明显变化.同时在64~500 Hz范围内的低频吸声性能均显著改善,特别是聚醚多元醇与异氰酸酯比例为100:60时,因加入羰基铁粉,使得磁性聚氨酯泡沫与聚氨酯泡沫相比,其低频吸声性能能够提高64%.该新型智能磁性聚氨酯泡沫有望通过调整特征参数来满足不同频段吸声的功能需求,可对智能吸声降噪器件的优化设计提供一定的参考价值.

In this paper, the addition of carbonyl iron particles addtion and the ratio of polyether polyol and isocyanate on the physical characteristics parameters and sound absorption performance of polyurethane foams（PUF） are investigated to improve the low frequency sound absorption effect of traditional polyurethane foam. Firstly, the least squares method is used to estimate the physical characteristic parameters of magnetic polyurethane foam（MPUF）, including flow resistivity, porosity, tortuosity, viscous length and thermal length, based on the Johnson-Champoux-Allard（JCA） acoustic propagation model. At the same time, sound absorption performance of 64–1600 Hz are tested by the transfer function method and impedance tube. The results show that adding carbonyl iron particles can obviously change the physical characteristic parameters of PUF/MPUF with the same ratio of polyether polyol and isocyanate. The flow resistivity and porosity are both increased by 82.9%–211.3% and 0.8%–5.3% respectively, while the tortuosity and the viscous length both decreased by 32.7%–74.5% and 81.4%–94.0% respectively. However, the thermal length has no obvious changes. The PUF/MPUF sound absorption performance of 64–500 Hz is significantly improved, and its low-frequency sound absorption performance can be increased by 64% due to the addition of carbonyl iron particles, especially when the ratio of polyether polyol and isocyanate is 100：60. The new intelligent MPUF is feasible to meet different functional requirements of the frequency sound absorption and offers references for the intelligent noise abatement device optimization design by MPUF.