Numerical Study of the Mixing Inside a Jet Stirred Reactor using Large Eddy Simulations

Jet Stirred Reactors (JSR) have been extensively used in the last decades to investigate gas phase chemical kinetics. Inside the JSR efficient mixing through turbulent jets is required in order to obtain homogeneous compositions. One of the best ways to achieve the mixing of the gas phase is to use turbulent jets obtained from nozzles. In our research, Computational Fluid Dynamics (CFD) simulations were applied to predict the mixing and flow field characteristics inside a spherical reactor. Large-Eddy Simulations (LES) were used to compute the residence time distribution and the mixing inside the JSR for different flow rates. Our simulations concern a non-reacting mixture at ambient conditions. The results agree well with tracer-decay data, experimentally measured using laser absorption spectroscopy, and with a CFD analysis of the mixing rate based on the Reynolds-Averaged Navier-Stokes (RANS) approach. Our simulations enable us to provide detailed information concerning the instantaneous turbulent structures which effectuate mixing inside the JSR.