Modeling of Turbulent Heat Transfer from an Array of Submerged Jets Impinging on a Solid Surface

ABSTRACT

Heat transfer from a row of turbulent jets impinging on a stationary surface is investigated numerically with the finite-difference algorithm SIMPLE. The jet-to-jet interaction, the geometric parameters of the jet array, and the effect of Reynolds number are investigated. The jets under consideration are submerged, planar, and exit the nozzle with a developed velocity profile. This study focuses on the turbulent regime (Re _j up to 72,300) using the Lam-Bremhorst version of the low-Re k–ϵ model. The notorious overpredictions in the stagnation region are alleviated using the Yap correction. Transition from laminar to turbulent flow is predicted via the Schmidt-Patankar production-term-modification model. Good comparison with experimental data is shown. Model results show that heat transfer is a maximum at the stagnation point and decreases with distance along the plate. At some point, heat transfer may exhibit an increase due to transition to turbulence. There is also a local maximum in Nusselt number at the midpoint between two jets, where the jets collide. The uniformity of heat transfer on the plate is a function of where and whether transition to turbulence occurs and the magnitudes of heat transfer at the stagnation and collision points. The modeling approach used here effectively captures both the stagnation region behavior and the transition to turbulence, thus forming the basis of a reliable turbulence model.