Scalar Transport Characteristics Near the Turbulent/Non-Turbulent Interface in a Reactive Jet Flow

Abstract

Turbulent/non-turbulent interface (T/NTI) layer separates the turbulent and non-turbulent regions. The study of T/NTI is helpful to deepen the understanding of mass transfer between turbulent and non-turbulent regions. In this paper, the chemical reaction and scalar transport characteristics of each component in the flow field near T/NTI were studied by numerical simulation of the two-stage non-equilibrium elementary reaction (A+B→R) flow field between the jet and the environmental flow. The results show that the convection term in the reactive jet flow field dominates the influence of scalar transport in the turbulent region. At the upstream region of the jet, the chemical reaction is more intense and gradually weakens along the flow direction. There are significant chemical reactions within and near the T/NTI layer. The chemical reactions near the downstream T/NTI layer mainly occur in the turbulent core region far away from the T/NTI layer. Near the T/NTI layer, the transport mechanism of reactant A and resultant R shows a similar but opposite trend. Near the irrotational boundary of the T/NTI layer, the transport of reactant A and resultant R is mainly affected by diffusion and convection, but their concentrations hardly change with time. The transport of reactant B in the T/NTI layer is mainly affected by convection. The remaining reactant B after the chemical reaction is blocked by the flow near T/NTI to transport to the irrotational boundary.

Keywords

• jet
• chemical reaction
• turbulent/non-turbulent interface layer
• scalar transport
• conditional average statistics