Numerical investigation of multiphase flow effects on mixed convection in partially heated hybrid nanofluid-filled cavity

The integration of cavities designed with distinct specifications enhances the convective heat transfer, leads to improved performance of engineering systems. The current research focuses on numerical investigation of mixed convection within the cavity, which features a partially heated wall and a rotating cylinder. The cavity is filled with hybrid nanofluid comprising Al₂O₃ and Cu nanoparticles suspended in water, serving as base fluid. The dimensionless governing equations were derived with a novel transformation of parameters along with consideration of the two-phase Buongiorno model. The input parameters examined included the Rayleigh number (10³≤Ra≤10⁶), the dimensionless radius of the cylinder (0.1≤R≤0.4), the angular rotational velocity of the cylinder (0≤Ω≤600), the concentration of nanoparticles (0.02≤ϕ≤0.05), and the dimensionless length of partially heated wall. Utilizing COMSOL Multiphysics as a simulation platform, Galerkin’s Weighted Residual Method is used to solve the governing equations. The impact of varying parameters is analyzed through the visualization of streamlines, dimensionless temperature with isothermal lines, normalized solid volume fraction, and their influence on both local and average Nusselt numbers. The observed results indicate an indirect relationship between average Nusselt number and the length of the partially heated wall. Moreover, the careful consideration of the varying parameters discussed leads to improved heat transfer performance of the hybrid nanofluid in the cavity. The highest value of Nusselt number attained is 8.9456 at ϕ_hnf=0.05, Ω=250 and R=0.2, underscoring a notable achievement that surpasses the values reported in previous works. The findings of this study offer valuable implications for optimizing convective heat transfer in applications, such as heat exchangers and electronic cooling systems.