Operator-splitting with ISAT to model reacting flow with detailed chemistry

We further increase the computational performance of an operator-split projection scheme for the solution of the equations governing reacting flows with detailed chemistry. This enhancement is achieved by using in situ adaptive tabulation (ISAT) to compute the pure reaction sub-steps; the treatment of diffusion and convection is unchanged. The modified scheme is applied to an unsteady one-dimensional laminar premixed methane–air flame problem using detailed GRIMech3.0 chemical kinetics. For this problem we demonstrate second-order temporal convergence, investigate the impact of the ISAT error tolerance on solution accuracy, and compare results with and without ISAT. Computational performance is also examined where we observe a reaction sub-step speed-up factor due to ISAT of approximately 13; the overall time step speed-up is approximately 7.5. Extension of the scheme to multiple dimensions is discussed.

keywords:

• Operator splitting
• ISAT
• projection
• tabulation
• flame

Acknowledgments

MAS acknowledges support from a NASA Graduate Student Researchers Program Fellowship and the Langley Research Center. SBP acknowledges support from the U.S. Department of Energy Grant No. DE-FG02-90ER14128. HNN has been supported by the U.S. Department of Energy (DOE), and by the DOE Office of Basic Energy Sciences (BES), Division of Chemical Sciences, Geosciences and Biosciences. Computations were performed at Sandia National Laboratories. Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94-AL85000.