CFD Investigation of Thermal Characteristics for a Dual Jet with a Parallel Co-flow

Abstract

A combined turbulent wall jet and offset jet (also known as the dual jet) with and without the presence of a parallel co-flow stream is studied. The standard k –ω turbulence model is used to predict the turbulent flow. The study focuses on the effects of the co-flow velocity (CFV) on the heat-transfer characteristics of the dual jet flow with the bottom wall maintained at a constant wall temperature. The CFV is varied up to 40% of the jet inlet velocity, and the height of the offset jet is varied from 5 to 11 times the jet width with the inlet Reynolds number taken as 15,000. The heat-transfer results reveal that the local Nusselt number ( Nu x ) along the bottom wall exhibits a peak at the immediate downstream of the nozzle exit, followed by a continuous decay in the rest of the converging region before showing a small rise for a short streamwise distance in the merging region. Further downstream, in the combined region, Nu x gradually decreases with the downstream distance. Except the merging region, no influence of co-flow is observed in the other two flow zones (converging and combined regions). In the merging region, for a given offset ratio (OR), Nu x remains nearly constant for a certain axial distance, and it decreases as the CFV increases. As a result of the increase in the CFV, the average Nusselt number decreases, indicating a reduction in overall convective heat transfer for higher values of the CFV. A regression analysis among the average Nusselt number ( ), CFV, and OR results in a correlation function in the form of within the range OR = 5–11 and CFV = 0–40%.

Impacts of using discrete and continuous porous layers on the cooling performance of confined multiple slot jet impingement under partially active magnetic field

“…Heat transfer (HT) with jet impingement (Je-Im) plays an important role in achieving higher localized HT coefficients where applications are encountered in drying, textiles, electronic cooling and many others (Koseoglu and Baskaya, 2010; Marzouk et al , 2022; Selimefendigil and Chamkha, 2020). In thermal management of electronic systems and photovoltaics (PVs), impinging jets can be used (Torbatinezhad et al , 2021; Bahaidarah, 2016; Selimefendigil and Öztop, 2022b; Mondal et al , 2022). The HT and flow process in impinging jets pose some challenges to be treated analytically due to complex interaction between the reversed flow, thermal field and pressure gradient along with the complex geometry of the cooled surface (Zuckerman and Lior, 2006; Weigand and Spring, 2009; Ajmi et al , 2020; Hnaien et al , 2022).…”

“…be used (Torbatinezhad et al, 2021;Bahaidarah, 2016;Selimefendigil and Öztop, 2022b;Mondal et al, 2022). The HT and flow process in impinging jets pose some challenges to be treated analytically due to complex interaction between the reversed flow, thermal field and pressure gradient along with the complex geometry of the cooled surface (Zuckerman and Lior, 2006;Weigand and Spring, 2009;Ajmi et al, 2020;Hnaien et al, 2022).…”