Simulation of natural convection heat transfer enhancement in a triangular enclosure filled with nanofluid using local thermal non-equilibrium model

The problem of steady natural convective heat transfer in an isosceles triangular shape enclosure filled with Fe3O4-kerosene nanofluid using local thermal non-equilibrium (LTNE) model in the presence of oriented magnetic field have been studied numerically in the present study. Two temperature model is used to represent the local thermal non-equilibrium between the fluid and particle phase. The inclined walls of the enclosure are maintained at constant low temperature whereas the bottom wall is considered as heated uniformly. Thermophoresis and Brownian motion effects are included in this study in the absence of chemical reaction. The Galerkin weighted residual finite element method has been employed to solve the governing partial differential equations after converting them into a non-dimensional form using a suitable transformation of variables. Comparison with previously published work is performed and excellent agreement is obtained. The effects of various model parameters such as Hartmann number and Rayleigh number on the streamlines and isotherms for fluid phase and particle phase have been displayed graphically for kerosene-Fe3O4 nanofluid. In addition, the heat transfer augmentation for Fe3O4-kerosene nanofluid for various combinations of the model parameter have been done in light of the average Nusselt number from the bottom heated wall. The obtained numerical results show that the average Nusselt number is an increasing function of the Rayleigh number while it is a decreasing function of the Hartmann number. Finally, it is observed that the heat transfer rate for both fluid and nanoparticle becomes same for larger value of Nield number, and as a consequence the fluid-particle phase have attained the identical temperatures and behave as local thermal equilibrium (LTE) state.