Vibrational effects on thermosolutal free convection of Cu-Al2O3/water nanofluids in a partially heated and salted square porous enclosure

Abstract

Vibration serves as an active mechanism for heat and mass transfer enhancement applied in numerous engineering sectors, including heat exchangers, electronic devices, aerospace applications, and solidification processes. This paper focuses on examining the effects of vibration on thermosolutal natural convection of a hybrid nanofluid within a porous medium. The system under investigation consists of a square enclosure subjected to horizontal thermal and solutal gradients generated by a centrally positioned source, with the top and bottom boundaries assumed to be adiabatic. The governing system of non-dimensional partial differential equations is derived through the introduction of appropriate dimensionless variables and parameters. The Corcione correlation was applied to model the thermal physical properties. Numerical solutions are obtained using the alternating direction implicit finite difference method, ensuring accuracy through successive tests and comparison with previously established results. Numerical simulations were conducted to assess the influence of vibration amplitude (?=1,3,5,10,20), frequency (?=500,1000,1500), nanoparticle volume fraction (0.01???0.05), Rayleigh number (50?Ra?200), Lewis number (1?Le?20) and buoyancy ratio (?2?N?2) on the convective instabilities of the fluid. The results show that gravitational modulation and fluid characteristics significantly influence convective stability. Increased vibration amplitude enhances both heat and mass transfer. However, higher frequencies reduce heat transfer while stabilizing mass transfer. Furthermore, higher Rayleigh numbers strengthen convective currents, thereby increasing both Nusselt and Sherwood numbers. The Lewis number also plays a critical role in these processes: lower values primarily improve heat transfer, whereas higher values enhance mass transfer. Additionally, positive buoyancy ratios lead to increases in both heat and mass transfer, whereas negative buoyancy ratios result in their reduction. © 2025 Elsevier B.V.