MHD combined convection in a channel with cavity using nanofluids

Abstract

Heat Transfer Enhancement in presence of magnetic field on combined convective flow in a horizontal channel with a bottom heated open cavity using nanofluids has been studied numerically. The horizontal lower surface is at a uniform temperature Th while vertical sides of the cavity along with the channel walls are adiabatic. The physical domain is filled with water based nanofluids containing Cu nanoparticles. The fluid enters from left with initial velocity Ui and temperature Ti and exits from right The physical problems are represented mathematically by different sets of governing two-dimensional equations along with the corresponding boundary conditions. Using a class of appropriate transformations, the governing equations along with the boundary conditions are transformed into non-dimensional form, which are then solved by employing a finite-element method based on Galerkin weighted residuals. The investigations are conducted for different values of Rayleigh number Ra (= 103 - 106), Reynolds number Re (= 100 – 500), Hartmann number Ha (= 0 – 20), solid volume fraction ϕ (= 0% – 15%), and physical parameter, cavity aspect ratio AR (= 0.5 - 2.0). Various characteristics such as streamlines, isotherms and heat transfer rate in terms of the average Nusselt number (Nuav), and average fluid temperature (θav) are presented for the aforesaid parameters. The results indicate that the mentioned parameters strongly affect the flow phenomenon and temperature field inside the cavity whereas in the channel these effects are less significant. Comparisons with previously published work are performed and the results are found to be in excellent agreement.