Cold obstacle influence on nanofluid convection in porous cavity

Abstract

Enclosure design has a substantial influence on thermal engineering procedures and technology, such as electronics, thermal exchangers, power engines, heating systems, solar panels, and nuclear power plants. Triangular enclosures with different aspect ratios are used for multiple-purpose optimization and enhanced thermal efficiency in microchannels. Triangle enclosures with cold cylinders are often used to reduce heat loss in thermal exchange devices and nanoscale thermal sinks. The objective of the current study is to explore the natural convection of a hybrid nanofluid within a wavy-bottom triangular porous cavity containing an embedded cold inverted triangle, all under the influence of an inclined magnetic field. The inner inverted triangle maintains a lower temperature, while the wavy bottom wall of the outer triangular cavity acts as an isothermal heat source at high temperatures. The space between the inner and outer triangles is filled with hybrid nanofluid (Ag–MgO– water). The numerical solution for the modeled mathematical framework is derived using the open-source finite element program COMSOL. A wavy triangle enclosure is used in this work to analyze key elements, such as the Hartmann number, Ha, the Rayleigh number, Ra, the volume fraction, ϕ, the Darcy number, Da, and the inclination, γ. The local distribution of streamlines, velocity profile, isotherms, and entropy production are demonstrated along with the average Nusselt number. The findings reveal that the heat transfer rate and the total entropy generation increase with increase in Da, while their values decrease with increase in Ha. The value of Nu is raised with increase in the volume fraction ϕ and Rayleigh number Ra. The velocity profile shows increase with increase in the volume fraction ϕ and Rayleigh number Ra.