Abstract

Heat transfer and fluid flow characteristics were computationally studied using passive oval protrusion, (POP), in a rectangular channel. The study employed rectangular computational domain of length 500 mm and width 170 mm for both smooth and roughened surface profiles. The simulations are carried out in three different aspect ratios corresponding to height of 5, 7 and 10 mm under a constant wall heat flux and for Reynolds numbers Re = 600, 1,000, 5,000, 7,000, 12000 and 15,000 in a rectangular duct. Having acquire the computational domain, the mesh integrity tests were carried using four different mesh sizes after which mesh size of 1.5 million cells were selected. The flow heat transfer and pressure drop characteristi c was simulated using Star CCM+ using the (k-omega) turbulence model. One side of the for walls are embellished with POP, these combined oval geometry protrusions are fixed on the top wall of the channel. Baseline results are validated for both friction factors and Nusselt numbers using Shah and London and Dittus Boelter correlations respectively. The results of temperature and pressure drop distributions along the mainstream channel are acquired analyze for the smooth and roughened surface are averaged and compared experiments ones. An enhancement in the rate of heat transfer was observed in the channel and an increase in heat transfer is observed as aspect ratio decreases, same trend is observed for friction factors. An optimum heat transfer effect of 14.3 % compared to the smooth case is noticed.