Molecular dynamics simulation of thermal conductivity of natural porous composites: Coupled regulation mechanism of moisture content and glycerol

Abstract

Thermal conductivity is a critical parameter that determines the thermal response, atomization efficiency, and release behavior of natural porous composites in heating-type aerosol generators. Although moisture and glycerol significantly affect the pore structure and heat transfer pathways of natural porous media, their coupling regulation mechanism at the molecular scale remains unclear. Based on the actual chemical components of natural porous composites (cellulose, hemicellulose, and lignin), a multi-component molecular model was established in this study. Molecular dynamics simulations were conducted under 36 working conditions with varying moisture content (0%–20%) and glycerol content (0%–20%). The results reveal that moisture serves as the dominant factor, which monotonically increases thermal conductivity by constructing continuous heat conduction pathways, with a maximum increment of 208.6%. Glycerol plays a secondary role: moderate addition reduces interfacial thermal resistance, while excessive addition induces molecular agglomeration and intensifies phonon scattering. Under dry conditions, the thermal conductivity presents a unimodal variation trend, and the optimal glycerol content ranges from 8% to 16%. A prominent synergistic enhancement effect exists between moisture and glycerol. When both contents reach 20%, the thermal conductivity peaks at 0.6185 W/(m·K). This study clarifies the heat transfer mechanism of natural porous composites applied in heating-type aerosol generators at the molecular scale, providing theoretical guidance for matrix formula design, aerosol additive optimization and thermal response performance regulation.