Magnetic field effect on the transient freezing of copper-water nanofluid flow in the channel using enthalpy-porosity technique

In this research, freezing of the copper-water nanofluid flow inside the channel with constant wall temperature was studied numerically. At the entrance to the channel, the velocity profile has been assumed to be developed. Nanofluid properties are extracted from the results of valid experiments. The thermal conductivity of the nanofluid is a function of the temperature. Nonlinear equations of continuity, momentum and energy conservation are solved with the finite volume method. The enthalpy-porosity technique is used to solve the phase change problem. In this study, the freezing of the nanofluid and base fluid (pure water) was compared. Using copper-water nanofluid instead of water causes the freezing process to slow down. It was observed that in the 12% volume fraction nanofluid, the thickness of the ice layer was reduced by about 40% relative to pure water under steady-state condition. In the freezing of water, the mushy zone is seen with visible thickness, while in the freezing of the nanofluid, this area is negligible. It was also observed that by applying the magnetic field, the freezing process is slowed down so that, in the Hartmann number 20, the thickness of the ice layer decreased by about 15% relative to the Hartmann number 0.