Numerical study on the mixing characteristics under transcritical and supercritical injection using large eddy simulation

Abstract

Large eddy simulations of cryogenic nitrogen injection are performed on both transcritical and supercritical injection and mainly attentions are focus on the jet disintegration mechanism and mixing layer feature. The simulation results reveal that the thermal disintegration mechanical dominates the disintegration characteristic under supercritical conditions. The jet disintegration is delayed and longer dense core region is detected for the transcritical injection due to the large density gradient effects. Because of this disintegration mechanism, the Reynolds stresses in the transcritical case are significantly suppressed in the turbulent fluctuation. In addition, we define a mixing layer based on the density gradient and thicker mixing layer interfaces are formed in the supercritical case. The relationship between transport properties and the large density gradient are also investigated, results indicate that the large density gradients are influenced by the pseudo critical temperature and transport properties.