Visualization of heat flow in a vertical channel with fully developed mixed convection

Abstract

A study on visualization of heat flow in three channels with laminar fully developed mixed convection heat transfer is performed. The first channel is filled with completely pure fluid; the second one is completely filled with fluid saturated porous medium. A porous layer exists in the half of the third channel while another half is filled with pure fluid. The velocity, temperature and heat transport fields are obtained both by using analytical and numerical methods. Analytical expression for heat transport field is obtained and presented. The heatline patterns are plotted for different values of Gr/Re, thermal conductivity ratio, Peclet and Darcy numbers. It is found that the path of heat flow in the channel strongly depends on Peclet number. For low Peclet numbers (i.e., Pe = 0.01), the path of heat flow is independent of Gr/Re and Darcy numbers. However, for high Peclet numbers (i.e., Pe = 5), the ratio of Gr/Re, Darcy number and thermal conductivity ratio influence heatline patterns, considerably. For the channels with high Peclet number (i.e., Pe = 5), a downward heat flow is observed when a reverse flow exits.

Effect of an inserted porous layer on heat and fluid flow in a vertical channel with mixed convection

“…The results of two approaches are compared to each other to be sure of the obtained analytical expressions. The condition of channel is similar to the channel of previous study of authors [16]; however the porous layer thickness is changed. The present study focused on both heat transfer and pressure drop through the channel by inserting of a porous layer.…”

“…The walls of vertical duct are assumed to be insulated. Celik and Mobedi [16] analyzed mixed convection in three vertical channels as fully filled clear fluid, fully filled fluid saturated porous medium, and half porous layer filled channel. They found analytical expressions for velocity, temperature, and heat function.…”