Diffusive lagrangian mixing simulation

Abstract

Diffusive Lagrangian Mixing Simulation (DLMS) is an adaptation of the Lagrangian Mixing Simulation (LMS) algorithm, taking in account the diffusive scales. LMS is a Lagrangian method that positions particles over a Eulerian velocity field to track the flow front between two fluids in a mixer. A mixing interface is formed where quantities such as interfacial area and segregation scales can be measured. In DLMS, the interface is only generated if the local segregation scale is above a threshold value, below which the contacting front between fluids is ruptured. The elimination of particles in diffusion dominated regions makes DLMS more realistic and in addition the computation is faster than in LMS. To develop and illustrate the application of DLMS, 2D CFD simulations of the flow in Confined Impinging Jets (CIJ) reactors are used. The comparison between DLMS and LMS results is done for a particular case, Re=600. Furthermore, the DLMS algorithm is here applied to active mixing cases, enabling their benchmark. DLMS particle tracking was simulated with first order method in a chaotic velocity field obtained from CFD simulations with second order method.