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." --
Download or read book Measurements and Modeling of Nitric Oxide Formation in Counterflow Premixed Ch4 O2 N2 Flames written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-27 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser-induced fluorescence (LIF) measurements of NO concentration in a variety of CH4/O2/N2 flames are used to evaluate the chemical kinetics of NO formation. The analysis begins with previous measurements in flat, laminar, premixed CH4/O2/N2 flames stabilized on a water-cooled McKenna burner at pressures ranging from 1 to 14.6 atm, equivalence ratios from 0.5 to 1.6, and volumetric nitrogen/oxygen dilution ratios of 2.2, 3.1 and 3.76. These measured results are compared to predictions to determine the capabilities and limitations of the comprehensive kinetic mechanism developed by the Gas Research Institute (GRI), version 2.11. The model is shown to predict well the qualitative trends of NO formation in lean-premixed flames, while quantitatively underpredicting NO concentration by 30-50%. For rich flames, the model is unable to even qualitatively match the experimental results. These flames were found to be limited by low temperatures and an inability to separate the flame from the burner surface. In response to these limitations, a counterflow burner was designed for use in opposed premixed flame studies. A new LIF calibration technique was developed and applied to obtain quantitative measurements of NO concentration in laminar, counterflow premixed, CH4/O2/N2 flames at pressures ranging from 1 to 5.1 atm, equivalence ratios of 0.6 to 1.5, and an N2/O2 dilution ratio of 3.76. The counterflow premixed flame measurements are combined with measurements in burner-stabilized premixed flames and counterflow diffusion flames to build a comprehensive database for analysis of the GRI kinetic mechanism. Pathways, quantitative reaction path and sensitivity analyses are applied to the GRI mechanism for these flame conditions. The prompt NO mechanism is found to severely underpredict the amount of NO formed in rich premixed and nitrogen-diluted diffusion flames. This underprediction is traced to uncertainties in the CH kinetics as well as in the nitrogen oxidation chemistry. S
Download or read book Measurements and Modeling of Nitric Oxide Formation in Counterflow Premixed CH4 O2 N2 Flames written by and published by . This book was released on 2000 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dimensionally Reduced Modeling of Nitric Oxide Formation for Premixed Methane air Flames with Ammonia Content written by and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical Kinetic Models for Combustion of Hydrocarbons and Formation of Nitric Oxide written by and published by . This book was released on 1980 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ammonia Conversion and NOx Formation in Laminar Coflowing Nonpremixed Methane air Flames written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper reports on a combined experimental and modeling investigation of NOx formation in nitrogen-diluted laminar methane diffusion flames seeded with ammonia. The methane-ammonia mixture is a surrogate for biomass fuels which contain significant fuel-bound nitrogen. The experiments use flue-gas sampling to measure the concentration of stable species in the exhaust gas, including NO, O2, CO, and CO2. The computations evolve a two-dimensional low Mach number model using a solution-adaptive projection algorithm to capture fine-scale features of the flame. The model includes detailed thermodynamics and chemical kinetics, differential diffusion, buoyancy, and radiative losses. The model shows good agreement with the measurements over the full range of experimental NH3 seeding amounts. As more NH3 is added, a greater percentage is converted to N2 rather than to NO. The simulation results are further analyzed to trace the changes in NO formation mechanisms with increasing amounts of ammonia in the fuel.
Download or read book Chemical Kinetic Models for Combustion of Hydrocarbons and Formation of Nitric Oxide written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-14 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: The formation of nitrogen oxides NOx during combustion of methane, propane, and a jet fuel, JP-4, was investigated in a jet stirred combustor. The results of the experiments were interpreted using reaction models in which the nitric oxide (NO) forming reactions were coupled to the appropriate hydrocarbon combustion reaction mechanisms. Comparison between the experimental data and the model predictions reveals that the CH + N2 reaction process has a significant effect on NO formation especially in stoichiometric and fuel rich mixtures. Reaction models were assembled that predicted nitric oxide levels that were in reasonable agreement with the jet stirred combustor data and with data obtained from a high pressure (5.9 atm (0.6 MPa)), prevaporized, premixed, flame tube type combustor. The results also suggested that the behavior of hydrocarbon mixtures, like JP-4, may not be significantly different from that of pure hydrocarbons. Application of the propane combustion and nitric oxide formation model to the analysis of NOx emission data reported for various aircraft gas turbines showed the contribution of the various nitric oxide forming processes to the total NOx formed. Jachimowski, C. J. and Wilson, C. H. Langley Research Center NASA-TP-1794, L-14106 RTOP 506-52-33-01...
Download or read book The Formation of Nitric Oxide in Diffusion Flames written by A. D. Tuteja and published by . This book was released on 1972 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Kinetics of Nitric Oxide Formation in Laminar and Turbulent Methane Combustion written by Gas Research Institute and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reduction of Nitric oxide Formation in Methane air Flames by Secondary air Injection written by Richard Leslie Gay and published by . This book was released on 1976 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nitric Oxide Formation in Gas Turbine Engines written by Thomas Mikus and published by . This book was released on 1978 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modelling Nitric Oxide Formation and the Effects of Trapped Residual Gas on Combustion in Spark ignition Engines written by S. Sotiriou and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theoretical Study of Nitric Oxide Formation in Constant Pressure Combustion Processes written by Md. Munawer Rasheed Khan and published by . This book was released on 1972 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Towards Robust Nitrogen Chemistry Model Development written by Antoine Durocher and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "An urgent transition of the energy sector to low-carbon sources has become necessary to mitigate the adverse impacts of the anthropogenic emissions of greenhouse gases (GHG). Chemical fuels consumed in combustion systems are expected to remain an important part of the energy landscape with their high energy and power densities. Whether it be hydrogen, ammonia, biofuels, or even metals, the combustion of any sustainable fuel in air will still emit nitrogen oxides (NOx). The detrimental consequences of NOx on both the human health and the environment have led to increasingly stringent regulations and a significant decrease in emissions from the energy sector. A better understanding of the NOx formation mechanisms is now needed to develop predictive models to help identify promising industrial designs and further reduce pollutant emissions. This work first implements an uncertainty quantification framework to evaluate the impact of inherent uncertainties present in thermochemical models on NOx concentration. The propagation of parametric uncertainty through flame simulations shows that emissions predictions can vary by up to 600% from the nominal solutions, highlighting the need for a comprehensive approach through inference to use independent experimental datasets targeting different formation pathways. In an effort to decouple the different production pathways, a series of experiments is designed with hydrogen as a fuel. Going back to the simplest fuel constrains the parametric set describing the combustion process and reduces the potential of model description errors. Velocity, temperature, and NO concentration measurements are performed in premixed, stagnation flames of hydrogen diluted with argon and helium at atmospheric and supra-atmospheric pressures. Axial velocity profiles, obtained with particle tracking velocimetry (PTV), provide a measure of the reactivity of the fuel-mixtures to assess the accuracy of the hydrogen-oxidation system. Temperature and NO concentration profiles are obtained from multi-line thermometry and NO laser-induced fluorescence (LIF), respectively, which achieves a detection of sub-ppm concentration levels in flames. Significant variability is observed between the predictions of different thermochemical mechanisms and measurements for both flame speed and NO concentration. Although recent models better capture the emissions formation, when using the same hydrogen-oxidation mechanism, the respective nitrogen chemistries exhibit large discrepancies. Inaccuracies in the oxidation chemistry can mask an inaccurate description of the nitrogen chemistry if models are adjusted, or optimized, to specific targets. Consequently, there is a need for improved oxidation mechanisms, as well, to enable the development of predictive thermochemical models. These measurements, and future NO investigations, used within the uncertainty quantification framework will enable an accurate and robust model development of the nitrogen chemistry to predict emissions with higher fidelity"--
Download or read book Nitrogen oxides NOx why and how they are controlled written by and published by DIANE Publishing. This book was released on 1999 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Combustion Chemistry written by W. C. Jr. Gardiner and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 515 pages. Available in PDF, EPUB and Kindle. Book excerpt: Detailed study of the rates and mechanisms of combustion reactions has not been in the mainstream of combustion research until the recent recognition that further progress in optimizing burner performance and reducing pollutant emission can only be done with fundamental understanding of combustion chemistry. This has become apparent at a time when our understanding of the chemistry, at least of small-molecule combustion, and our ability to model combustion processes on large computers have developed to the point that real confidence can be placed in the results. This book is an introduction for outsiders or beginners as well as a reference work for people already active in the field. Because the spectrum of combustion scientists ranges from chemists with little computing experience to engineers who have had only one college chemistry course, everything needed to bring all kinds of beginners up to the level of current practice in detailed combustion modeling is included. It was a temptation to include critical discussions of modeling results and computer programs that would enable outsiders to start quickly into problem solving. We elected not to do either, because we feel that the former are better put into the primary research literature and that people who are going to do combustion modeling should either write their own programs or collaborate with experts. The only exception to this is in the thermochemical area, where programs have been included to do routine fitting operations. For reference purposes there are tables of thermochemical, transport-property, and rate coefficient data.
Download or read book Modeling Nitric Oxide Formation in a Swirl Burner with Flue Gas Recirculation written by James G. Rice and published by . This book was released on 1973 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
