Download or read book Nitric Oxide Formation and Modelling Uncertainty from Exhaust-gas-diluted Methane Flames written by Antonio Lipardi and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Nitrogen oxides (NOx) are pollutants emitted by various combustion processes that are subject to increasingly-stringent regulations due to their impact on human health and the environment. Exhaust gas recirculation (EGR) has been shown to reduce NOx emissions by decreasing the oxygen concentration and, for a given heat release, reducing peak flame temperatures. Previous simulated combustion results (at a constant burning temperature) have demonstrated that EGR dilution may generate an NO minimization range governed by an increase in the prompt NO formation and a decrease in the thermal NO rate. However, this range is not predicted by all combustion models, thereby necessitating its experimental validation.This thesis conveys the constant burning temperature effects of EGR on NOx formation and the modelling performance of three thermochemical mechanisms (Gri-Mech 3.0, San-Diego 2005, and Combustion Science and Engineering). Using NO planar laser-induced fluorescence (NO-PLIF) and particle tracking velocimetry (PTV), constant burning temperature (1850K and 2000K) measurements of nitric oxide (NO-PLIF), temperature (NO-PLIF), and flame reactivity (PTV) were performed on methane-air flames with (and without) EGR dilution using a counterflow apparatus. These results confirmed the existence of the EGR-induced NO minimization range. However, this interesting engine design constraint was obscured by the high level of variability (factor of approx. 4) and uncertainty (up to 99%) found in the simulated NO profiles. A reduced set of reactions that may serve as a basis for the optimization process of the investigated NO submodels is also presented." --