Numerical simulation study of mixed convection in a cavity filled with homogeneous porous material and open to horizontal channel for (Al₂O₃, Cu, TiO₂/water) tri-hybrid nanofluid flow

Heat transfer of tri-hybrid nanofluid flows in porous media is very important in many industrial and mechanical applications. Still, previous studies have not explored the flow of a tri-hybrid nanofluid by mixed convection within a cavity filled with a porous material and open to a horizontal channel. This study introduces a novel approach for numerically analyzing the mixed convection of ternary water-based hybrid nanoparticles (Al 2 O 3 , Cu, and TiO 2 ) in a two-dimensional rectangular cavity filled with a homogeneous porous medium. The cavity is equipped with a heat source and has an opening to a horizontal channel. The research investigates how the placement of the heat source affects flow characteristics and heat transfer. The cavity’s heat source is in two different positions (left wall, right wall), while the remaining walls of the studied configuration are assumed to be adiabatic. The fluid flow in the porous region was modeled using the Darcy–Brinkman–Forchheimer equation. The governing equations were analyzed using ANSYS-FLUENT, a finite volume-based computational fluid dynamics (CFD) solver. The simulations were conducted under the laminar flow regime, employing a finite volume scheme as the methodological framework. The results are analyzed for flow isothermal, velocity contour distributions, and average Nusselt numbers, on a set of Richardson numbers ([Formula: see text], volume fraction of ternary hybrid of nanoparticles ([Formula: see text]), Darcy numbers ([Formula: see text]), with [Formula: see text]. The study results showed that the average Nusselt number increases as the Richardson number decreases (Ri[Formula: see text]) in both cases of forced convection dominance, due to the reduced effect of buoyancy forces. Heat transfer increases as Darcy’s number increases by increasing stronger heat spirals. Conversely, the convective efficiency decreases by 16.90%, with an increment in fractional size of nanoparticles increasing from [Formula: see text] to [Formula: see text] due to the increase in fluid viscosity. Furthermore, it is declared that the left thermal wall exhibits the highest average Nusselt number, with a heat transfer improvement of 33.17% at Ri=10 compared to the right wall. The results of this study can be put into practice in a range of heat treatment systems for heat exchangers.