Design of core-shell particles for low thermal emissivity coatings using Mie scattering and Monte Carlo simulations
International Journal of Thermal Sciences, cilt.228, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 228
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.ijthermalsci.2026.111006
- Dergi Adı: International Journal of Thermal Sciences
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, INSPEC, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Anahtar Kelimeler: Low thermal emissivity, Core-shell particles, Mie scattering, Monte Carlo simulation, Surrogate-based optimization, Radiative transfer equation
- Boğaziçi Üniversitesi Adresli: Evet
Özet
Suppressing long-wave infrared (7-14 μm) emission through coatings is important for controlling radiative heat transfer from near room-temperature surfaces. Core-shell particles dispersed in a matrix provide a way to achieve low emissivity. However, the performance of such coatings depends on the optimal selection of core and shell materials and dimensions, which is systematically investigated in this work through computational design of dielectric-metal core-shell particles. A two-stage approach in which Mie theory is used to calculate single-particle scattering efficiencies (Qext, Qabs) and the asymmetry parameter g first, followed by Monte Carlo simulations to calculate the reflectance, transmittance, and emissivity after selecting the optimal particles is adopted. A surrogate-based optimizer that natively handles mixed variables explores ten dielectric materials for core and five metals for shell material selection. The objective is to minimize emissivity by maximizing backscattering (negative g) and minimizing absorption (Qabs/Qext). The surrogate-based optimizer identifies AlN/Ag (995 nm/100 nm) in vacuum and ZnO/Ag (1093 nm/100 nm) in polymer medium as leading candidates. Subsequent coating-level Monte Carlo simulations give band-averaged (7-14 μm) emissivity values of 0.32 and 0.43, respectively, under ideal non-absorbing host assumptions. The results indicate that a high-index dielectric core with approximately 1 μm radius and 100 nm Ag shell provides a favorable trade-off between backscattering enhancement and absorption suppression. Monte Carlo simulations demonstrate a 55% reduction in net radiative heat flux in the 7-14 μm band for polymer embedding case compared to a high-emissivity reference at Ts = 320 K and T∞ = 295K. Validation studies are performed to confirm numerical convergence, spectral resolution adequacy, and energy conservation. This research presents a computational framework for radiative transfer control in particulate media.