Impacts of Heat Flux Distribution, Sloping Magnetic Field and Magnetic Nanoparticles on the Natural Convective Flow Contained in a Square Cavity

In the present paper,the effect of the heat flux distribution on the natural convective flow inside a square cavity in the presence of a sloping magnetic field and magnetic nanoparticles is explored numerically.The nondimensional governing equations are solved in the framework of a finite element method implemented using the Galerkin approach.The role played by numerous model parameters in influencing the emerging thermal and concentration fields is examined;among them are:the location of the heat source and its lengthH
,the magnitude of the thermal Rayleigh number,the nanoparticles shape and volume fraction,and the Hartmann number.It is found that the nanofluid velocity becomes higher when the thermal source length,the nanoparticles volume fraction and/or the thermal Rayleigh number are increased,while it decreases as the Hartmann number Ha grows and the position of the heat source moves toward the center of the lower wall of the cavity.Moreover,the temperature of the nanofluid grows with the extension of the thermal source and decreases slowly when the heat flux position moves toward the center of the lower wall.The outcomes of the research also indicate that the average Nusselt number becomes smaller on increasing Hartmann number Ha and heat source length H^(*).The addition of Fe_(3)O_(4) to engine oil leads to a higher rate of heat transfer with respect to the addition of SiO_(2) particles.Blade-shaped nanoparticles generate the highest value of the Nusselt number compared to all the other considered shapes.

Natural convective heat transfer in a square enclosure utilizing magnetic nanoparticles

In the present paper,unsteady natural convective heat transfer flow inside a square enclosure filled with nanofluids containing magnetic nanoparticles using nonhomogeneous dynamic model is investigated numerically.The horizontal top wall of the enclosure is considered a colder wall and the bottom wall is maintained at uniform temperature whereas two other vertical walls of the cavity are thermally insulated.The Galerkin weighted residual finite element method has been used to solve the governing non-dimensional partial differential equations.In numerical simulations,four types of nanoparticles such as magnetite(Fe_(3)O_(4)),cobalt ferrite(CoFe_(2)O_(4)),Mn-Zn ferrite(Mn-ZnFe_(2)O_(4)),and silicon dioxide(SiO2),and three types of base fluids such as water(H_(2)O),engine oil(EO)and kerosene(Ke)have been considered.Comparisons with previously published work are performed and excellent agreement is obtained.The effects of various model parameters such as thermal Rayleigh number,nanoparticles volume fraction and nanoparticles shape factor are studied.The results show that the average Nusselt number increases as the thermal Rayleigh number and nanoparticles volume fraction intensify.The results indicate that the average Nusselt numbers are higher for the blade shape of nanoparticles.