Mixed convection heat transfer enhancement using phase change material in silver core–shell nanoparticles: Numerical modeling and thermophysical optimization
Journal of Energy Storage, cilt.172, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 172
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.est.2026.123050
- Dergi Adı: Journal of Energy Storage
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, INSPEC
- Anahtar Kelimeler: Core-shell nanoparticles, Latent Functionally Thermal Fluid (LFTF), Latent heat storage, Mixed convection, NEPCM
- Yıldız Teknik Üniversitesi Adresli: Evet
Özet
This study investigates the enhancement of mixed convective heat transfer in a lid-driven square cavity filled with PCM@Ag core–shell nanoparticles and silver (Ag) nanoparticles dispersed in water. The composite PCM@Ag particles consist of an n-eicosane core encapsulated with Ag, combining latent heat storage with enhanced thermal conductivity. Existing correlations for the thermophysical properties of core–shell nanoparticles are reformulated as functions of α, defined as the ratio of the core radius to the particle radius. The study focuses on the key parameters: the core-to-particle ratio α (0 ≤ α ≤ 1), the Richardson number (0.01 ≤ Ri ≤ 100), and the nanoparticle volume fraction φ (0 ≤ φ ≤ 0.04). Computations are performed using the finite volume method, employing the SIMPLE algorithm for pressure-velocity coupling and a second-order upwind scheme for discretization. Model accuracy is verified through grid independence tests and validated against benchmark solutions. Using a structured decision-making approach, the optimal core–shell ratio is determined as α = 0.9. Adopting this value, the mean result finding at a particle volume fraction of φ = 0.04 and for Richardson numbers between 0.01 and 1 shows that PCM@Ag nanofluids increase the average Nusselt number by about 6% compared to water, while Ag/water nanofluids improve it by about 3% under the same conditions. For Ri ≥ 10, both nanofluids produce a comparable enhancement of ~8% relative to water at Ri = 100, indicating that they exhibit similar behavior under dominant natural convection conditions.