Numerical study of heat transfer from an isothermally heated flat surface due to turbulent twin oblique confined slot-jet impingement

The heat transfer from an isothermally heated flat surface due to two-dimensional turbulent twin oblique confined slot-jet impingement is studied numerically using the ANSYS FLUENT commercial code. Initially the flow and thermal fields for a normal confined slot-jet impingement are investigated using the RNG k-ε model and the SST k-ω model, and their performance is evaluated against experimental data. The local Nusselt number distribution predicted by the SST k-ω model agrees notably better with the existing experimental data. Subsequently, the SST k-ω model is employed to study the twin oblique impinging jet heat transfer problem. Systematic parametric study is conducted by varying the jet exit Reynolds number (Re = 23,000 and 50,000), the jet-to-jet separation distance (L = 0, 2, and 4), the jet exit to the target plate distance (H = 2.6, 4, and 6), and the inclination angle of the jet to the impingement surface (45° ≤ φ ≤ 90°). Results indicate that, as the impingement angle is reduced from 90° (normal impingement), the peak Nusselt number at the impingement surface is gradually reduced and its location slightly shifts away from the jet axis with a corresponding slight decrease of the average Nusselt number for any combination of Re, L, and H. The average Nusselt number is a strong direct function of the Reynolds number and the impingement angle whereas it is a weak inverse function of the jet to target plate separation distance.