Effect of Inclination of Twin Jets Impinging a Heated Wall

Authors

1 Theoretical and Applied Laboratory of Fluid Mechanics, Physics Faculty, USTHB, Algiers, Algeria

2 GRESPI / Lab. de Thermomécanique- Université de Reims Champagne-Ardenne- 51687 Reims, France

Abstract

This study examines the interaction of twin oblique turbulent slot-jets of different directions (divergent, convergent or parallel) impinging a heated wall. A comparison of the results is done between the cases of perpendicular jets and three cases of twinned jets (parallel, convergent and divergent).The twin slot jets are located on a confining adiabatic wall at a distance of 8 slot jet width. Convective heat is investigated numerically examining the effect of Reynolds number (Re) and jet inclination angle (). This problem is relevant to a wide range of practical applications including nuclear engineering devices, manufacturing, material processing, electronic cooling, drying paper or textile, tempering of glass, etc. The numerical investigation is performed using two dimensional large eddy simulations (LES) approach with Smagorinsky sub-grid scale (SGS) models. The results show the presence of a complex flow resulting from the interaction of the two jets. When the impingement angle is reduced from 0° (perpendicular impingement) to 60°, the position of the stagnation points are modified and therefore the peaks of the Nusselt number locations on the impingement surface and their magnitude, vary. For largest Reynolds number Nusselt number is enhanced for all types of inclination. The averaged Nusselt number shows that the perpendicular impingement gives better heat transfer than that of the oblique jets. The poor heat transfer is obtained for the parallel oblique jets. For the same angle, divergent jets give smallest heat transfer than the convergent jets.

Keywords

Journal of Applied Fluid Mechanics
Volume 12, Issue 2
March 2019
Pages 403-411

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