TREATING CHEMISTRY IN COMBUSTION WITH DETAILED MECHANISMS - IN-SITU ADAPTIVE TABULATION IN PRINCIPAL DIRECTIONS PREMIXED COMBUSTION

A new method to treat chemical reactions in combustion problems with d etailed mechanisms is developed. The method is called in situ adaptive tabulation in principal directions (ISATPD). The tabulation is done i n situ during combustion calculations and is made in the first few pri ncipal directions of the composition space. The integration of the gov erning equations of chemical reactions is made using detailed mechanis ms. Test calculations of the premixed pairwise mixing stirred reactor (PPMSR) are performed for methane/air combustion with a skeletal mecha nism consisting of 16 species and 40 reactions, and for natural gas co mbustion with the GRI 2.11 mechanism consisting of 49 species and 279 reactions. Results show that this method has excellent accuracy (for a ll species) and efficiency. A speedup in performing chemistry of 1,665 is obtained for the methane/air combustion system with the skeletal m echanism. The speedup will increase as the calculation continues since less integrations will be performed. (C) 1998 by The Combustion Insti tute.