scholarly journals Soot Emission Simulations of a Single Sector Model Combustor Using Incompletely Stirred Reactor Network Modeling

2021 ◽  
Author(s):  
Savvas Gkantonas ◽  
Jenna M. Foale ◽  
Andrea Giusti ◽  
Nondas Mastorakos
Keyword(s):  
Network Modeling ◽  
Soot Emission ◽  
Sector Model ◽  
Stirred Reactor ◽  
Reactor Network

scholarly journals Soot Emission Simulations of a Single Sector Model Combustor Using Incompletely Stirred Reactor Network Modeling

2020 ◽  
Author(s):  
Savvas Gkantonas ◽  
Jenna M. Foale ◽  
Andrea Giusti ◽  
Epaminondas Mastorakos
Keyword(s):  
Particle Size ◽  
Soot Particle ◽  
Mixture Fraction ◽  
Computational Cost ◽  
Chemical Mechanism ◽  
Lean Burn ◽  
Sector Model ◽  
Stirred Reactor ◽  
Complex Chemistry ◽  
Reactor Network

Abstract The simulation of soot evolution is a problem of relevance for the development of low-emission aero-engine combustors. Apart from detailed CFD approaches, it is important to also develop models with modest computational cost so a large number of geometries can be explored, especially in view of the need to predict engine-out soot particle size distributions (PSDs) to meet future regulations. This paper presents an approach based on Incompletely Stirred Reactor Network (ISRN) modeling that simplifies calculations, allowing for the use of very complex chemistry and soot models. The method relies on a network of Incompletely Stirred Reactors (ISRs), which are inhomogeneous in terms of mixture fraction but characterized by homogeneous conditional averages, with the conditioning performed on the mixture fraction. The ISRN approach is demonstrated here for a single sector lean-burn model combustor operating on Jet-A1 fuel in pilot-only mode, for which detailed CFD and experimental data are available. Results show that reasonable accuracy is obtained at a significantly reduced computational cost. Real fuel chemistry and a detailed physicochemical sectional soot model are consequently employed to investigate the sensitivity of ISRN predictions to the chemical mechanism chosen and to provide an estimate of the soot particle size distribution at the combustor exit.

scholarly journals Soot Emission Simulations of a Single Sector Model Combustor Using Incompletely Stirred Reactor Network Modeling

2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Savvas Gkantonas ◽  
Jenna M. Foale ◽  
Andrea Giusti ◽  
Epaminondas Mastorakos
Keyword(s):  
Mixture Fraction ◽  
Computational Cost ◽  
Chemical Mechanism ◽  
Lean Burn ◽  
Sector Model ◽  
Stirred Reactor ◽  
Low Emission ◽  
Aero Engine ◽  
Complex Chemistry ◽  
Reactor Network

Abstract The simulation of soot evolution is a problem of relevance for the development of low-emission aero-engine combustors. Apart from detailed CFD approaches, it is important to also develop models with modest computational cost so that a large number of geometries can be explored, especially in view of the need to predict engine-out soot particle size distributions (PSDs) to meet future regulations. This paper presents an approach based on Incompletely Stirred Reactor Network (ISRN) modeling that simplifies calculations, allowing for the use of very complex chemistry and soot models. The method relies on a network of incompletely stirred reactors (ISRs), which are inhomogeneous in terms of mixture fraction but characterized by homogeneous conditional averages, with the conditioning performed on the mixture fraction. The ISRN approach is demonstrated here for a single sector lean-burn model combustor operating on Jet-A1 fuel in pilot-only mode, for which detailed CFD and experimental data are available. Results show that reasonable accuracy is obtained at a significantly reduced computational cost. Real fuel chemistry and a detailed physicochemical sectional soot model are consequently employed to investigate the sensitivity of ISRN predictions to the chosen chemical mechanism and provide an estimate of the soot PSD at the combustor exit.

scholarly journals On the Influence of Kinetic Uncertainties on the Accuracy of Numerical Modeling of an Industrial Flameless Furnace Fired With NH3/H2 Blends: A Numerical and Experimental Study

2020 ◽  
Vol 8 ◽  
Author(s):  
Marco Ferrarotti ◽  
Andrea Bertolino ◽  
Ruggero Amaduzzi ◽  
Alessandro Parente
Keyword(s):  
Numerical Models ◽  
Molar Fraction ◽  
Kinetic Scheme ◽  
Sensitivity Study ◽  
Pure Hydrogen ◽  
Fuel Blend ◽  
Stirred Reactor ◽  
Flameless Burner ◽  
Reactor Network ◽  
The Impact

Ammonia/hydrogen-fueled combustion represents a very promising solution for the future energy scenario. This study aims to shed light and understand the behavior of ammonia/hydrogen blends under flameless conditions. A first-of-its-kind experimental campaign was conducted to test fuel flexibility for different ammonia/hydrogen blends in a flameless burner, varying the air injector and the equivalence ratio. NO emissions increased drastically after injecting a small amount of NH3 in pure hydrogen (10% by volume). An optimum trade-off between NOx emission and ammonia slip was found when working sufficiently close to stoichiometric conditions (ϕ = 0.95). In general, a larger air injector (ID25) reduces the emissions, especially at ϕ = 0.8. A well-stirred reactor network with exhaust recirculation was developed exchanging information with computational fluid dynamics (CFD) simulations, to model chemistry in diluted conditions. Such a simplified system was then used in two ways: 1) to explain the experimental trends of NOx emissions varying the ammonia molar fraction within the fuel blend and 2) to perform an uncertainty quantification study. A sensitivity study coupled with latin hypercube sampling (LHS) was used to evaluate the impact of kinetic uncertainties on NOx prediction in a well-stirred reactor network model. The influence of the identified uncertainties was then tested in more complex numerical models, such as Reynolds-averaged Navier–Stokes (RANS) simulations of the furnace. The major over-predictions of existing kinetic scheme was then alleviated significantly, confirming the crucial role of detailed kinetic mechanisms for accurate predictive simulations of NH3/H2 mixtures in flameless regime.

NOx Scaling Characteristics for Industrial Gas Turbine Fuel Injectors

2000 ◽  
Author(s):  
Donald W. Kendrick ◽  
Anuj Bhargava ◽  
Meredith B. Colket ◽  
William A. Sowa ◽  
Daniel J. Maloney ◽  
...  
Keyword(s):  
Bluff Body ◽  
Thermal Characteristics ◽  
Fuel Injectors ◽  
Stirred Reactor ◽  
Primary Zone ◽  
Mass Fractions ◽  
Chemistry Modeling ◽  
Flame Chemistry ◽  
Reactor Network ◽  
Industrial Gas Turbine

An experimental and numerical investigation into the effects of nozzle scale was undertaken at the U.S. Federal Energy Technology Center in conjunction with the United Technologies Research Center. Experiments were conducted at operating pressures from 6.8 to 27.2 atm., and at primary zone equivalence ratios from 0.4 to 0.75. Results reported herein summarize tests at 6.8 atm., and with zero and 4% piloting levels (expressed as mass fractions of total fuel). Computations used to compare to the experimental data were made using the GRI Mech 2.11 kinetics and thermodynamics database for flame chemistry modeling. A perfectly stirred reactor network (PSR) was used to create a network of PSRs to simulate the flame. From these investigations, concentrations of NOx and CO expressed in parts per million (ppm) were seen to increase and remain virtually unchanged, respectively, when comparing a Quarter to Full Scale Bluff-Body (Tangential Entry) nozzle. Simple heat transfer modeling and CO emissions refuted that any variations in thermal characteristics within the combustors were solely responsible for the observed NOx variations. Using PSR network modeling, the NOx trends were explained due to variations in macroscopic mixing scales which increased with nozzle size, thereby creating progressively less uniform mixing, and hence higher NOx levels.

Effects of Hydrogen Fueling on NOx Emissions: A Reactor Model Approach for an Industrial Gas Turbine Combustor

2017 ◽  
Author(s):  
D. Kroniger ◽  
M. Lipperheide ◽  
M. Wirsum
Keyword(s):  
Gas Turbine ◽  
Flow Reactor ◽  
Plug Flow ◽  
Nox Emissions ◽  
Flame Zone ◽  
Gas Turbine Combustor ◽  
Reactor Model ◽  
Stirred Reactor ◽  
Set Up ◽  
Reactor Network

Addition of hydrogen (H2) to gas turbine fuel has recently become a topic of interest facing the global challenges of CO2 free combustion. As a drawback, Nitrogen oxide (NOx) emissions are likely to increase in hydrogen-rich fuel combustion which in return limits the use of the technology. In the course of this development, a model-based quantification of NOx emission increase by fuel flexibility may identify possible operation ranges of this technology. This paper evaluates the effect of an increased hydrogen fraction in the fuel on the NOx emissions of a non-premixed 10 MWth gas turbine combustor. A simple reactor network model has been set up using a perfectly stirred reactor (PSR) to simulate the flame zone and a plug flow reactor (PFR) to simulate the post flame zone. The change of residence time in the flame zone is accounted for by an empirical expression. The model is validated against data from high-pressure test rig experiments of an industrial non-premixed gas turbine combustor. The model results are in good agreement with the experimental data. Based on the model results, a fundamental correlation of the effect of hydrogen on the NOx emissions is formulated.

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