Optimization and sensitivity analysis of hydromagnetic convective heat transfer in a square cavity filled with a porous medium saturated by Ag-MgO/water hybrid nanofluid using response surface methodology

Abstract

A computational exploration is presented to emphasis on optimization and sensitivity inspection of the unsteady free convective heat transfer flow of hybrid nanofluid in a square cavity under multidirectional periodic magnetic field with aluminum foam porous medium. The vertical walls of the cavity are maintained at constant low temperature whereas the constant as well as the variable thermal conditions on the bottom wall is considered and the top wall is considered as adiabatic. The finite element technique has been applied to solve the governing equations after changing them into dimensionless form. In the numerical simulations, the Ag-MgO/water hybrid nanofluid has been engaged to gain insight into the flow and thermal arenas. The obtained outcomes are exhibited in terms of streamlines, isotherms and average Nusselt number as well as plotting the response surface and contours. The average Nu is displayed in line graphs, response surface and contours graphs as well as tabular form for different flow parameters. Response surface methodology is applied to achieve an optimization procedure to search for the best situation in which the highest heat transfer rate occurs when the distinct model parameters namely Darcy number, porosity and hybrid nanoparticles volume fraction are treated as the sensitivity of the parameters. A correlation equation between the output response and input variables has been derived with the help of response surface methodology. The magnetic field and its path regime the flow decoration of hybrid nanofluid suggestively. The Ag and Ag-MgO nanomaterial with water flow arenas are compared. While considering Ag-H2O nanofluid, the average Nu increases 23.97 % at Ra = 107 with ϕhnp = 0.02 whereas the corresponding increases is 25.68 % if the Ag-MgO/H2O hybrid nanofluid is taken into account. The average Nu upsurges suggestively, as hybrid nanoparticles volume fraction, period number, magnetic field leaning angle, Darcy number and Rayleigh number rises but porosity and Hartmann number have inverse effect. The outcomes showed that the average Nu is more sensitive to the hybrid nanoparticles volume fraction rather than the porosity or Darcy number. Also, it is discovered that the optimum condition arises at Da = 0.001, ε = 0.2 and ϕhnp = 0.02 with the final Nuave = 2358.21.