Primary Pollutant Prediction from Integrated Thermofluid-Kinetic Pulse Combustor Models

Abstract

A phenomenological model for pulsating combustion by predicting characteristics of primary pollutants NOx and CO, as well as minor combustion species via integration with a detailed kinetic mechanism (GRI-Mech2.11) and areduced kinetic model, both derived from the CHEMKIN suite is studied with the aim of improvement. Homogeneous methane-air mixtures have been modeled across a range of practical, fuel-lean operating conditions, and predictions of primary pollutants from both models have been compared with available data. The use of a more realistic oscillatory Nusselt number is necessary to provide agreement with the experimental finding of relative insensitivity of primary pollutant emissions to input power. Oscillatory characteristics of combustion species are generated and are consistent with published data. Optimum operating conditions of the combustor are predicted to be around an equivalence ratio of 0.74, where NOx and CO emissions of only a few parts per million occur. NOx and CO predictions using the reduced mechanism provide better agreement with experimental data than those using GRI-Mech2.11. This probably results from the construction of the reduced model from the detailed mechanisms in GRI Mech3.