Turbulent Reacting Flow Simulation Based on the Multi-Environment Mixing ModelO. Mierka, J. Stopka, M. Kiša, and Ľ. Jelemenský Department of Chemical and Biochemical Engineering, Faculty of Chemical and Food Technology, Slovak University of Technology, SK-812 37 Bratislava
E-mail: jan.stopka@stuba.sk Abstract: In this work a CFD approach is described for modelling fast chemical reactions in turbulent liquid flows. The relevant model developed for this purpose is composed of a core for the solution of Navier—Stokes equations and extended with an appropriate turbulence model. Treatment of additional (passive or active) scalars is performed on the basis of velocity fields obtained by means of a “hydrodynamic core engine”. The developed CFD model was benchmarked on the so-called backward-facing step problem and reasonably correlated with the values reported. The turbulence model used to simulate micromixing phenomena was derived from the scalar dissipation rate, which is obtained from the turbulent kinetic energy and its dissipation. For this purpose, a multi-environment mixing model was developed. This model enables modelling of the flow of nonpremixed environments of liquid phases, where chemical reactions do not occur, and also the flow of environments with different reaction rates due to different temperatures and concentrations of species involved. Generally, in the case of modelling of N environments and S chemical species, the use of such micromixing approach means evaluation of N+(N − 2) S+N−1 additional scalar fields of individual environments, temperatures, and species in these environments. As a reaction system, a commonly used set of competitive-consecutive reactions (A + B → 2P A+ P → 2R) occurring in a triple-jet channel reactor was considered. Simulations were executed in 2D. Their results, however, need validation by experimental data. Full paper in Portable Document Format: 596aa394.pdf
Chemical Papers 59 (6a) 394–402 (2005) |
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