The Impact of Impingement Surface Angle Variation and Channel Design on Heat Transfer Performance and Flow Characteristics for Twin Jet Impingement

Abstract

This study intends to give a detailed research of surface angles of impingement, and jet-plate distances to enhance heat transfer and improve the channel’s flow structure features for twin jet impingement. For this aim, numerical analysis of twin jet impingement was carried out for distinct impingement surface angles (\(\alpha\)) of 30°, 45°, and 60° and impinging jet-plate distances (H) of 3, 4.5, and 6. The numerical investigation was performed as a steady, two-dimensional, employing the \(k\)-\(\varepsilon\) turbulence model and the Ansys–Fluent program in the twin jet rectangular channel. While the isothermal flat plate impingement surface has 310 K (T\(_{{\rm H}}\)), the impinging air jet fluid temperature is 300 K (T). The obtained outcomes were compared with the numerical and experimental outcomes of the work in the literature and it was noticed that they are determined to be compatible. The results were presented as the local Nu number (Nu\(_{L}\)) variations for \(\alpha=30^{\circ}\), 45° and 60° impingement surface angles along the flat plate impingement surface, and the variations of mean Nu numbers (Nu\(_{m}\)) for different \(\alpha\) and H values with the Re number ranges of 20000–50000. Besides, streamlines and temperature isotherms were evaluated for different \(\alpha\), H and Re number values by visualising them in detail. The results displayed that while the Nu\(_{m}\) values are higher than the case without angle (\(\alpha=0^{\circ}\)) for all angles and H values, after the 30° angle, the Nu\(_{m}\) values decrease slightly at 45° and 60°. Accordingly, for H = 6, the Nu\(_{m}\) value of 30° impingement surface angle is 3.09% higher than that in 60°.