Mixed convective heat transfer in an open cavity with fins

Abstract

This work numerically explores the mixed convective heat transfer in an open square enclosure containing conducting fins fixed to the heated vertical wall. This kind of work with fins has enormous potential due to its applications in research, engineering, and current industries. Therefore, the current work is highly significant to understand the impact of mixed convection. The external flow enters from the hole in the bottom wall and leaves from the hole in the upper wall. The left vertical wall of the enclosure is heated isothermally, and the fins are attached to the heated walls at a uniform height. Both the upper and lower walls are adiabatic, whereas the right sidewall is at a lower temperature. The non-dimensional transport equations are resolved by using the finite element method. The study is accomplished for the wide control variables range, such as Reynolds number (50 ≤ Re ≤ 200), Richardson's number (0.1 ≤ Ri ≤ 10), the length of the fins (L_f = 0.2, 0.4, and 0.6), the size of the outlet opening (W_out = 0.1, 0.2, and 0.3), and the gaps in between the outlet hole and left heated wall (S = 0, 0.45, and 0.9). The results show that the thermal performance of the open enclosure is meaningfully affected by the control parameters. The maximum and minimum heat transfer happens when the position of the outlet opening is at the left (S = 0) and right (S = 0.9), respectively. The heat transfer improves by raising the Ri and Re, whereas increasing the fin's length and distance between the outlet opening and left wall reduces heat transfer significantly. The $N{u}_{\mathrm{avg}}$ rises 13% with a decrease in the fin's length $\left(L_f\right)$ from 0.6 to 0.2 at Re = 200, S = 0 due to the improvement of the convection on the heated wall. Also, $N{u}_{\mathrm{avg}}$ increases by 15% when Ri increases from 1 to 9.