Estimation and experiment of acoustic properties of rice straw (estimation of sound absorption coefficient using CT images)

Plant-derived biomass, as a carbon-neutral resource, has gained prominence in recent years, with widespread applications in fuels, building materials, and other domains. The sound-absorbing characteristics of these materials, attributable to their shape and size, have been extensively studied. In this paper, we perform a theoretical estimation of the sound absorption coefficient using CT scan images of actual rice straw. The circumference of the internal structure and the void areas were determined from CT scan tomograms, and the normal-incidence sound absorption coefficient was then computed. The tortuosity of the rice straw was measured, and a theoretical sound absorption coefficient was derived using the tortuosity-adjusted effective density. The circumference and the cross-sectional area of the gaps in the rice straw cross-section were ascertained using CT tomographic images, enabling the theoretical estimation of the sound absorption coefficient. Overall, the theoretical values calculated in this study are deemed to be reasonable and corroborate the experimental findings.