Investigation of density ratio effects on normally injected cold jets into a hot cross flow

In this work, hydrodynamic effects of multiple squared cross-section cold jets inclined normally into a hot cross flow were computationally simulated using large eddy simulation (LES) approach. The finite volume method and the SIMPLE algorithm on a multi-block non-uniform staggered grid were applied. The jet into cross flow velocity ratio and the jet Reynolds number were 0.5 and 4,700, respectively. Simulations were performed for three different jets into cross flow temperature ratios, namely, 2, 1, and 0.5, corresponding to density ratios of 0.5, 1, and 2. The experimental and numerical results of Ajersch et al. (J. Turbomachinery 119(2), 330–342, 1997) at unit density ratio were used for validation purposes. The density ratio effects on the flow characteristics were investigated. It was shown that the density ratio has significant effects on the hydrodynamics of the jet into cross flow problems and even though the flow Mach number may be low, its effects due to temperature differences between the jet and the cross flow cannot be easily ignored.