Chemical Kinetics Mechanism Reduction Based on Principal Component Analysis: Development and Testing of Some New Implementations.

摘要

Principal component analysis of local sensitivity (PCAS) coefficients was investigated as a means for producing finite-rate chemistry submodels for computational fluid dynamics models. A programmable approach for reducing chemical kinetics mechanisms, PCAS appeared to have some potential advantages over the trial mechanism method (TMM) the U.S. Army Research Laboratory has been employing for mechanism reduction. However, it was found that published PCAS approaches were unable to produce viable mechanisms as small as those produced by the TMM. Therefore, some PCAS variations were implemented and tested. To compare the effectiveness of the variations to published PCAS and TMM implementations, results for two test cases were obtained. One, which involved a relatively small H2-O2 mechanism, demonstrated the variations implementation and potential benefit. The other, which involved a moderately complex mechanism for monomethylhydrazine-red fuming nitric acid (MMH-RFNA), better tested the variations potential for applications of interest. In the MMH-RFNA test case, none of the implemented variations produced viable mechanisms with sizes as small as those produced by the TMM. However, the results suggest that a PCAS-based approach, employed as a means for understanding the role specific reactions play in sets produced by the TMM, could prove useful. In addition, because PCAS approaches have the potential to be less computationally demanding than the TMM, there may be applications for which it would be beneficial to employ a PCAS-based reduction approach prior to employing the TMM.