DNS of turbulent combustion with detailed chemistry on theCenju -

Direct Numerical Simulation (DNS) of reacting ows became, in the last decade, one of the most attractive tools to study turbulent combustion. A high order nite diierence method is used here to perform DNS of methane-air ames. An eecient parallel implementation based on domain decomposition methods in order to perform DNS on MPP platforms is presented in this paper. A 64 processor Cenju-3 computer was used to execute simulations of premixed methane air ames. Two dimensional ame-turbulence interactions were considered that match thermochemical and hydrodynamical parameters of an experimental investigation reported by Buschmann et al. in 1994. Main ndings of previous DNS studies and observations in the experimental study were connrmed. In accordance with the latter study it is found that maximum levels of OH radicals do not deviate much from the maximum level in laminar ames. However, the laminar amelet speed and maximum reaction rates are aaected sig-niicantly by the turbulent ow eld. Thus OH radicals are not suitable to represent these changes in these conngurations. The basic understanding of turbulent combustion, its prediction in practical applications and its control are fundamental problems in combustion research and technology. Any progress in this area has an immediate impact on many practical devices (e.g. piston engines and jet engines). However studying turbulent combustion is complicated by the coupling of various complex phenomena, such as turbulence, molecular transport and chemical reactions. Therefore using only analytical and asymptotic theories turns out to be insuucient to address these kind of problems. Even precise experiments do not always provide the required information (e.g. ame wall interactions) and are often quite expensive. In this framework Direct Numerical Simulation (DNS) became an attractive tool in the past few years that has proved to be valuable in addressing fundamental physical questions and in the construction of models for turbulent combustion. \DNS" in the following designates numerical simulations of the Navier-Stokes equations without any turbulence model. That means that all scales of turbulence and chemical reactions are fully resolved. DNS therefore provides data with the same precision as experiments of the same connguration. Both experimental and numerical investigations of the role of chemical reaction kinetics in turbulent combustion are complicated by the strong coupling of hydrodynamics with thermochemistry and by resolution requirements: hydrodynamic and ther-modynamic spatial and temporal scales span many orders of magnitude in ames with high Reynolds and Damkk ohler numbers (the latter being the ratio of …