Direct Numerical Simulation of Chemically Reacting Flows with the Public Domain Code OpenFOAM

A new solver for direct numerical simulation (DNS) of chemically reacting flow is introduced, which is developed within the framework of the open-source program OpenFOAM. The code is capable of solving numerically the compressible reactive flow equations employing unstructured grids. Therewith a detailed description of the chemistry, e.g. the reaction rates, and transport, e.g. the diffusion coefficients, has been accomplished by coupling the free chemical kinetics program Cantera. The solver implies a fully implicit scheme of second order for the time derivative and a fourth order interpolation scheme for the discretization of the convective term. An operator-split approach is used by the solver which allows solutions of the flow and chemistry with time scales that differ by orders of magnitude, leading to a significantly improved performance. In addition, the solver has proved to exhibit a good parallel scalability. The implementation of the code has first been validated by means of one-dimensional premixed flames, where the calculated flame profiles are compared with results from the commercially Chemkin code. To demonstrate the applicability of the code for three-dimensional problems, it has been applied to simulate the flame propagation in an explosion vessel of laboratory-scale. A computational grid with 144 million finite volumes has been used for this case. The simulation has been performed parallel on 8192 processors from the HERMIT cluster of HLRS. The calculated burning velocity agrees well with the experimental data.