MIXING IN TURBULENT COAXIAL JET

Abstract

This paper studies the mixing process in a compressible turbulent coaxial jet, using a Large Eddy Simulation (LES) type approach. Two cases were considered: Case 1, a passive scalar injected into the annular jet and Case 2, a passive scalar injected into the central jet. This study is based was articulated on the implementation of a modern and efficient a high-performance and modern numerical method to meet both the results accuracy and calculation cost requirements. A new solver for the linearization of the equation’s characteristic of the approximate Riemann problem was used to calculate inviscid fluxes. The mean and instantaneous mixture fraction were traced and analysed. Then, using the probability density function, the mixture quality was studied. Results The results of this study provided useful information. In particular, active mixing regions were associated with high concentrations of Root Mean Square (RMS) values. Coherent vortices play a very important role in the mixing process, and the efficiency of the mixture is maintained when the passive scalar is injected into the central jet. All results obtained are in agreement with similar experimental results of the simulation jets in this study.

Keywords

• Large Eddy Simulation
• mixing
• Riemann problem