Thermal management optimization of natural convection in a triangular chamber: Role of heating positions and ternary hybrid nanofluid

In this paper, we used the multi-relaxation time lattice Boltzmann method to investigate natural convection in a triangular-shaped cavity filled with a tri-hybrid nanofluid. The cavity is partially heated by a chip of fixed size (l=L/2), the position of which varies on the left and bottom walls in order to find the optimal positions. The inclined side is maintained at a cool temperature, while the other parts are adiabatic. A detailed analysis is carried out on the impact of four essential parameters on the optimization of heat transfer: the Rayleigh number, ranging between Ra = 103 and Ra = 106; the partial heating position, showing the cavity in six different configurations; the fluid type, including pure water, nanofluid, hybrid nanofluid, and tri-hybrid nanofluid; and finally, the volume concentration of the nanoparticles for three values, ϕ = 0%, 3%, and 6%. Results are presented in the form of isotherms, streamlines, temperature and velocity profiles, and the mean Nusselt number values. As the results show, the position of the partial heater plays a crucial role, influencing natural convection heat transfer significantly in certain positions at all values of the Rayleigh number. The type of fluid has a remarkable impact on the amplification of natural convection at large values of the Rayleigh number, where the buoyancy force becomes strong. Notably, the use of tri-hybrid nanofluid shows a clear improvement in natural convection heat transfer. Furthermore, a substantial increase in thermal transmittance is observed with an increasing nanoparticle volume fraction. The validation results agree well with both numerical results and experimental data published in the literature.