CALTECH ASCI TECHNICAL REPORT 137 Reduction of Detailed Chemcial Reaction Networks for Detonation Simulations

While a detailed mechanism represents the state-of-the-art of what is known about a reaction network, its direct implementation in a fully resolved CFD simulation is all but impossible (except for the simplest systems) with the computational power available today. This paper discusses the concept of Intrinsic Low Dimensional Manifold (ILDM), a technique that systematically reduces the complexity of detailed mechanisms. The method, originally developed for combustion systems, has been successfully extended and applied to gaseous detonation simulations 2,3,4. Unfortunately, while a one-dimensional ILDM is reasonably easy to compute, manifolds of higher dimensions are notoriously difficult. Moreover, the selection of the manifold dimension has been largely arbitrary, with a one-dimensional ILDM being the most popular if for no other reason than that it is easiest to compute and store. In this paper, we will present a technique that enables us to quantitatively determine the dimensionality of the ILDM needed, as well as a robust and embarrassingly parallel algorithm for computing high-dimensional ILDMs. Finally, these techniques are demonstrated in the context of a one-dimensional ZND detonation with detailed chemistry.