MHD & EHD: Magnetic Field Effect on Nanofluid

Magnetic Field Effect on Nanofluid in a 2D Channel

Description

This project simulates the effect of a magnetic field on a nanofluid in a two-dimensional channel using ANSYS Fluent software. The problem is carried out and investigated through CFD analysis.

The present model is designed in two dimensions using Design Modeler software. Because of its symmetrical geometry, the model is drawn as a two-dimensional channel. It has a length of 0.49 m and a width of 0.01 m, with an inlet boundary on the left and an outlet boundary on the right. The lower boundary of the domain is defined as the central axis, and adjacent to the channel's outer wall, a boundary is defined as the interface between the fluid and solid regions.

The meshing of the present model is performed using ANSYS Meshing software. The mesh type is structured, and the number of elements is equal to 9,282.

Magnetic Field Methodology

When metal or alloy particles of very small dimensions, on the order of the nano-scale, are mixed into a base fluid, a nanofluid is produced. Such fluids have applications such as enhancing heat transfer thanks to the conductivity of the metals.

In this simulation, the effect of a magnetic field on the nanofluid's behavior and heat transfer is investigated. For this purpose, the magnetohydrodynamic (MHD) model is used, and the magnetic field is defined using the magnetic induction method. With this method, an external magnetic field is generated to apply a specific magnetic flux in different directions of the Cartesian coordinate system.

The nanofluid defined in the model is based on iron oxide (Fe₃O₄) and contains 2% nanoparticles. It has a density of 1081.158 kg/m³, a specific heat capacity of 3841 J/kg·K, a thermal conductivity of 0.640835 W/m·K, and a viscosity of 0.001055 kg/m·s. A constant magnetic field is applied, with a magnetic flux of 1 tesla defined only along the y-axis, corresponding to the radial direction of the channel.

In terms of boundary conditions, an insulation condition is applied to the outer wall of the channel, meaning that no electric current passes through it. For the inner wall and the common boundary between the solid and fluid parts of the model, a coupling condition is used to transmit electric current in both directions. The nanofluid stream enters the channel with a velocity of 0.0837 m·s⁻¹ and a temperature of 300 K, and exits at a pressure equal to atmospheric pressure. The outer wall of the channel is held at a constant thermal condition with a temperature of 320 K.

The laminar model and the energy equation are enabled to solve the fluid flow equations and to calculate the temperature distribution inside the domain, respectively.

Magnetic Field Conclusion

At the end of the solution process, two-dimensional contours of pressure, velocity, temperature, and the magnetic field in the horizontal and vertical directions are obtained. In addition, a diagram of the perpendicular magnetic field variation along the longitudinal direction of the channel's central axis is produced. The present results show the effect of applying a magnetic field and a thermal boundary condition on the nanofluid flow and its heat transfer.