Characterization of an adaptive technique to reduce combustion thermochemistry

International audienceThe study of combustion requires the description of the thermochemistry of elementary reactions. Modern detailed chemical kinetic description of hydrocarbon mixtures combustion with air involves tens of species and hundreds of elementary reactions. Since each of these elementary reactions evolve at timescales which may span over several orders of magnitudes, the resulting model is inherently stiff. These characteristics imply that the numerical integration of the detailed thermochemical evolution equations is the most expensive task when a detailed description of combustion chemistry is sought, for instance, in computational fluid dynamics models. This work presents a technique, dubbed in situ adaptive tabulation (ISAT), which has been implemented in order to reduce the integration time of the system of equations governing the thermochemical evolution of reactive mixtures. The technique is tested in a modification of the classical Partially Premixed Reactor (PaSR) called Pairwise Mixing Stirred Reactor (PMSR) and the results obtained characterize the efficiency of the algorithm, demonstrating a reduction of up to 46% in computational time when compared to the direct integration of the governing equations