Finite element simulation for heatline visualization of natural convective flow and heat transfer inside a prismatic enclosure

Finite element simulation is performed visualizing heat flow through heatlines for a free convection flow and heat transfer in an air-filled prismatic enclosure. This configuration has applications in collecting solar energy in attic spaces of greenhouses and buildings having pitched roofs. The top inclined walls of the enclosure are considered at constant low temperature, two vertical walls are adiabatic whereas the bottom wall is heated isothermally as well as non-isothermally. The Galerkin weighted residual finite element method is used to solve the governing non-linear partial differential equations. The simulated results are displayed through streamlines, isotherms and heatlines to examine the effects of buoyancy on the flow and thermal fields. The Rayleigh number's effects on average temperature and velocity fields are also calculated and displayed graphically. The results indicate that for a uniformly heated bottom wall both the average temperature and the average velocity in the cavity are higher compared to the non-uniformly heated bottom wall. Furthermore, heatlines were observed to predict the energy transfer better than those of the isothermal lines.