A cell agglomeration algorithm for accelerating detailed chemistry in CFD

Abstract

Abstract A cell agglomeration algorithm is proposed to mitigate the computational cost of incorporating detailed chemical kinetics in multi-dimensional Computational Fluid Dynamics (CFD) simulations. Cells that are close in species and energy composition space are agglomerated before calling the reaction integrator, substantially reducing the number of chemistry integrations. The algorithm is generalized and applicable to any reacting flow configuration, and the accuracy is fully controllable. A dynamic hash table is used to efficiently bin cells into high dimensional hyper-cubes in composition space. The method is applied to four different CFD simulations and the speed-up and incurred error are assessed for a range of agglomeration tolerances and table dimensions. The proposed approach exhibits up to an order of magnitude speed-up with a relatively moderate decrease in accuracy. Keywords: cell agglomerationdetailed chemical kineticsCFDcomputation accelerationmulti-zone and reactor network Acknowledgements The financial support of the Austrian Kplus programme funded by the Federal Government of Austria as well as the State Governments of the federal states of Styria and Lower Austria is gratefully acknowledged. Notes 1Cell Agglomeration can be similarly applied to particle-based methods where the word 'particle' in the following text can be substituted for the word 'cell'