Double diffusion heat convection of a porous enclosure loaded with nano-encapsulated phase change materials

Abstract

No doubt that the recovery of the wasted heat and the maximizing of heat transmission rates are of great interest to engineers and scientists due to their direct impact on global warming. In this article, The thermal efficiency of a Latent Heat Storage (LHS) system was numerically studied with the aim of augmenting its performance. The Double-diffusive convection of Nano-encapsulated phase change material (NEPCM), confined in an annulus between an inner Koch snowflake cylinder and an outer hexagon, is considered and analyzed. A key contribution of this study is the application of a stabilized Galerkin finite element method)GFEM(for numerical modeling. The study spans a broad range of parameters, including Rayleigh numbers (Ra = 10³ to 10⁶), Darcy parameters (Da = 10⁻² to 10⁻⁵), Lewis numbers (Le = 0.1 to 5), and the inner cylinder shape (triangle, Koch snowflake). The results are presented in the form of streamlines, isotherms and heat capacity ratio (Cr). The findings suggested that increasing Ra and Da significantly augmented the heat transfer rates, while the impact of Le was less important. At the highest studied Ra, increasing Da to 10⁻⁵ and improved heat transmission rate by 160 %, whereas it decreased by 22 % when Le increased to 5. Moreover, it was noted that the triangular body has a better heat transmission rate in comparison with the other two bodies. The triangular shape resulted in a 116 % increment in the heat transmission rate compared to the snowflake shape.