Author: Justin Jeekee ShumPublisher:
ISBN: 9780494930724
Category :
Languages : en
Pages :
Book Description
The Development and Validation of a Simplified Soot Model for Use in Soot Emissions Prediction in Natural Gas Fuelled Engine Simulations
Author: Justin Jeekee ShumPublisher:
ISBN: 9780494930724
Category :
Languages : en
Pages :
Book Description
Engine Modeling and Simulation
Author: Avinash Kumar AgarwalPublisher: Springer Nature
ISBN: 9811686181
Category : Technology & Engineering
Languages : en
Pages : 368
Book Description
This book focuses on the simulation and modeling of internal combustion engines. The contents include various aspects of diesel and gasoline engine modeling and simulation such as spray, combustion, ignition, in-cylinder phenomena, emissions, exhaust heat recovery. It also explored engine models and analysis of cylinder bore piston stresses and temperature effects. This book includes recent literature and focuses on current modeling and simulation trends for internal combustion engines. Readers will gain knowledge about engine process simulation and modeling, helpful for the development of efficient and emission-free engines. A few chapters highlight the review of state-of-the-art models for spray, combustion, and emissions, focusing on the theory, models, and their applications from an engine point of view. This volume would be of interest to professionals, post-graduate students involved in alternative fuels, IC engines, engine modeling and simulation, and environmental research.
Development and Validation of a Partially Coupled Soot Model for Turbulent Kerosene Combustion in Industrial Applications
Author: Bijan ShahriariDevelopment and Validation of a Partially Coupled Two-equation Soot Model for Industrial Applications
Author: Kaveh KhalilianDevelopment and Assessment of a Soot Emissions Model for Aircraft Gas Turbine Engines
Author: Bastien MartiniPublisher:
ISBN:
Category :
Languages : en
Pages : 114
Book Description
Assessing candidate policies designed to address the impact of aviation on the environment requires a simplified method to estimate pollutant emissions for current and future aircraft gas turbine engines under different design and operating assumptions. A method for NOx and CO emissions was developed in a previous research effort. This thesis focuses on the addition of a soot mechanism to the existing model. The goal is to estimate soot emissions of existing gas turbine engines within soot measurement uncertainties, and then to use the method to estimate the performance of potential future engines. Soot is non-volatile primary particulate matter. In gas turbine engines the size rarely exceeds l [mu]m. The soot is composed almost exclusively of black carbon, is an aggregate of nearly spherical carbon primary particles, and exhibits fractal behavior. Results of other studies regarding soot nucleation, growth, oxidation, and coagulation rates are integrated within a network of perfectly-stirred reactors and shown to capture the typical evolution of soot inside a gas turbine combustor, with soot formed in the early parts of the combustor and then oxidized. The soot model shows promising results as its emissions estimates are within the measurement uncertainties. Nevertheless, model uncertainties are high. They are the consequence of the large sensitivity to input variables. Therefore, the validity of the model is limited to cases with available engine data. More engine data are needed to develop and assess the soot model.
Prediction of Soot Formation in Laminar Opposed Diffusion Flame with Detailed and Reduced Reaction Mechanisms
Author: Hojoon ChangPublisher:
ISBN:
Category : Combustion
Languages : en
Pages :
Book Description
The present work focuses on a computational study of a simplified soot model to predict soot production and destruction in methane/oxidizer (O2 and N2) and ethylene/air flames using a one-dimensional laminar opposed diffusion flame setup. Two different detailed reaction mechanisms (361 reactions & 61 species for methane/oxidizer flame and 527 reactions & 99 species for ethylene/air flame) are used to validate the simplified soot model in each flame. The effects of strain rate and oxygen content on the soot production and destruction are studied, and the soot related properties such as soot volume fraction, particle number density and particle diameter are compared with published results. The results show reasonable agreement with data and that the soot volume fraction decreases with higher strain rate and lower oxygen content. The simplified soot model has also been used with two reduced reaction mechanisms (12-step, 16-species for methane flame and 20-species for ethylene flame) since such reduced mechanisms are computationally more efficient for practical application. The profiles of the physical properties and the major species are in excellent agreement with the results using the detailed reaction mechanisms. However, minor hydrocarbon-species such as acetylene (C2H2) that is the primary pyrolysis species in the simplified soot model is significantly over predicted and this, in turn, results in an over-prediction of soot production. Finally, the reduced reaction mechanism is modified to get more accurate prediction of the minor hydrocarbon-species. The modified reduced reaction mechanism shows that the soot prediction can be improved by improving the predictions of the key minor species.
Modeling the Impact of Fuel Composition on Aircraft Engine NOx̳, CO and Soot Emissions
Author: Lukas Frederik Jakob BrinkPublisher:
ISBN:
Category :
Languages : en
Pages : 114
Book Description
Aircraft NO[subscript x], CO and soot emissions contribute to climate change and lead to negative air quality impacts. With the aim of quantifying the effects of fuel composition on NO[subscript x], CO and soot emissions, a combustor model named Pycaso is developed. The combustor model consists of a 0D/1D reactor network, coupled with a soot model. The model predicts NO[subscript x], CO and soot emissions at sea level conditions for a CFM56-7B engine using conventional jet fuel. The model matches existing methods to predict cruise NO[subscript x] emissions within 5% and cruise CO emissions within 30%. It is shown that the volume -- and thus time -- over which secondary air is mixed with the fuel-air mixture in the combustor is the most important factor in determining the magnitudes of the modeled emissions. The sensitivity of modeled NO[subscript x] and CO emissions to thrust at thrust settings below 15% is shown to be the consequence of "cold" unburned fuel entering the secondary zone of the combustor. The model is used to assess two possible emission mitigation solutions: removing naphthalene from jet fuel and replacing conventional jet fuel with 50:50 biofuel blends. The removal of naphthalene through hydrotreating is found to lead to mean reductions in soot emissions of 15% [12%–20%] for mass and 9% [5%–19%] for number. The range captures variations in engine operating conditions, soot model configurations and compositions of the baseline jet fuel. Similarly, the removal of naphthalene through extractive distillation reduces soot mass emissions by 32% [29%–48%] and number emissions by 23% [14%–45%]. The mean reductions associated with using 50:50 biofuel blends are 43% [34%–59%] for soot mass and 35% [14%–45%] for soot number. Using biofuel blends is also predicted to result in a reduction in NO[subscript x] emissions of 5% [4%–7%] and a 3% [2%–4%] decrease in CO emissions.
Large Eddy Simulation of Soot Evolution in Turbulent Reacting Flows
Author: Michael Edward MuellerPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Soot particles are nanoparticles consisting primarily of carbon that are formed during the combustion of fuel-rich mixtures. Due to environmental and health concerns, soot emissions from combustion systems are tightly regulated, and this regulation will only become stricter in the future. To enable the design of the next generation of low-emission combustion systems, predictive numerical simulations will be required. However, soot is a particularly difficult modeling problem due to the needs for high-fidelity models for soot itself in addition to chemistry and turbulence. This dissertation seeks to develop an integrated modeling framework based on Large Eddy Simulation (LES) for soot evolution in turbulent reacting flows. The final objective is the demonstration and evaluation of the model in an actual aircraft combustor. In order to enable these high-fidelity simulations, three component models have been developed. First, a detailed soot model is developed within the framework of the Method of Moments. New models for soot aggregation and fragmentation are proposed, and closure of the moment source terms is achieved with the Hybrid Method of Moments (HMOM), an accurate yet computationally efficient method. Second, a new turbulent combustion model is developed based on the Radiation Flamelet/Progress Variable (RFPV) model that can account for the removal of precursors from the gas-phase to form soot particles. Third, a subfilter PDF model is developed to account for the unresolved small-scale interactions between soot, turbulence, and chemistry. The subfilter PDF approach is validated a priori against a recent DNS database of soot evolution in a turbulent nonpremixed flame. The integrated modeling approach is then validated against experimental measurements in two laboratory-scale turbulent nonpremixed flames: a natural gas piloted jet flame and an ethylene bluff body flame. Differences in soot evolution due to the differences in the large-scale mixing in the two flames are discussed. The validated model is then applied to the simulation of a Pratt & Whitney aircraft combustor. Two operating points are simulated to assess the ability of the integrated model to reproduce quantitative trends in soot emissions.
Technical Literature Abstracts
Author: Society of Automotive EngineersPublisher:
ISBN:
Category : Technical literature
Languages : en
Pages : 400
Book Description
Author: Armin Veshkini