Heat Transfer Prediction of a Jet Impinging a Cylindrical Deadlock Area

Abstract

The turbulent heat transfer by a confined jet flowing inside a hot cylindrical cavity is investigated numerically in this paper. This configuration is found in several engineering applications such as air conditioning and the ventilation of mines, deadlock, or corridors. The parameters investigated in this work are the Reynolds number (Re, 20,000 < Re <50,000) and the normalized distance Lf between jet exit and the cavity bottom (Lf , 2 <Lf < 12). The numerical predictions are performed by finite volume method using the second order one-point closure turbulence model (RSM). The Nusselt number increases and attains maximum values at stagnation points, after it decreases. For an experimental test case available in the literature Lf = 8, the numerical predictions are in good agreement. Processes of heat transfer are analyzed from the flow behavior and the underlying mechanisms. The maximum local heat transfer between the cavity walls and the flow occurs at Lf = 6 corresponding to the length of the potential core. Nusselt number at the stagnation point is correlated versus Reynolds number Re and impinging distance Lf ; [Nu0 =f{Re,Lf)j.

Numerical Investigations on Heat Transfer of Self-Sustained Oscillation of a Turbulent Jet Flow Inside a Cavity

“…The knowledge about the local heat transfer coefficient distribution on the impinging wall is very important for the control processes in any of these applications to obtain high-quality products. Many publications have confirmed the dependence of the heat transfer with some number of parameters, such as Reynolds number, temperature, the impinging distance, the lateral confining wall, and the nozzle shape [1][2][3][4][5][6][7]. The present work is on the subject of a plane isothermal fully developed turbulent jet issuing into a rectangular hot cavity (Fig.…”

“…Therefore, the self-sustained oscillations are produced by the periodic deflection of the jet axis due to the Coanda effect [8,[10][11][12][13]. Contrary, the case of the axisymmetric jet flowing in a cylindrical cavity (3D flow) remains steady for all jet location inside cavity [5,7].…”

“…But, when the jet width is reduced compared at that of cavity, from a certain width, these oscillations are attenuated because the third component of the velocity in the z-direction becomes significant due to the side wall effect and a 3D flow is occurred. For this reason, the case of a circular jet in a cylindrical cavity is always steady in average [5,7]. So one may consider this problem as bidimensional.…”