Numerical and Experimental Investigation of Confined Turbulent Multiple Transverse Jets

Abstract

The flow and mixing properties of confined transverse jets are relevant to a myriad of combustion devices ranging from propulsion to energy generation and chemical processing. The current effort focuses on understanding the mixing process between a transverse jet mixing in a confined system. The current study involves the simulation of a single confined transverse jet configuration under matched conditions of a companion experiment. The main flow Reynolds number considered is in the range of 25000 -53000 and the jet-to-main flow momentum flux ratio is varied from 3.2 -14.3. The momentum and scalar mixing is investigated through the solution of the Reynolds-Averaged Navier Stokes (RANS) equations. The mean scalar mixing characteristics are compared to experimental data. The turbulence model that is used is the low Reynolds number k-ϵ model. Due to demonstrated symmetry, only a one-half section of the geometry is considered. All numerical simulations capture salient flow structures such as the counter-rotating vortex pair (CRVP). The current investigation shows the numerical simulations predict the experimental data with a good degree of accuracy. Nomenclature A, b, c = empirical constants C = local mean mass fraction of the jet C = average mass fraction of the jet over the cross sectional area A D = diameter J = momentum flux ratio m  = mass flow rate n = number of jets Q = volume flow rate r = velocity ratio x = stream-wise coordinate y = cross stream coordinate j = subscript for jet flow Us = Unmixedness 1 Senior Scientist AFRL/RQRC,