Analysis of high pressure premixed flames using Equivalent Reactor Networks for predicting NOx emissions

Lyra, S.; Cant, RS

doi:10.1016/j.fuel.2012.12.066

Cited by 30 publications

(24 citation statements)

References 17 publications

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“…The lack of correct representation of the detailed chemistry has been pointed as the main source of inconsistency. 23 Due to this fact, approaches using CRNs have gained relevance, as chemistry can be modeled in detail while keeping the computational costs relatively low.…”

Section: Introductionmentioning

confidence: 99%

Emission Modeling of an Interturbine Burner Based on Flameless Combustion

et al. 2018

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Since its discovery, the flameless combustion (FC) regime has been a promising alternative to reduce pollutant emissions of gas turbine engines. This combustion mode is characterized by well-distributed reaction zones, which potentially decreases temperature gradients, acoustic oscillations, and NOx emissions. Its attainment within gas turbine engines has proved to be challenging because previous design attempts faced limitations related to operational range and combustion efficiency. Along with an aircraft conceptual design, the AHEAD project proposed a novel hybrid engine. One of the key features of the proposed hybrid engine is the use of two combustion chambers, with the second combustor operating in the FC mode. This novel configuration would allow the facilitation of the attainment of the FC regime. The conceptual design was adapted to a laboratory scale combustor that was tested at elevated temperature and atmospheric pressure. In the current work, the emission behavior of this scaled combustor is analyzed using computational fluid dynamics (CFD) and chemical reactor network (CRN). The CFD was able to provide information with the flow field in the combustor, while the CRN was used to model and predict emissions. The CRN approach allowed the analysis of the NOx formation pathways, indicating that the prompt NOx was the dominant pathway in the combustor. The combustor design can be improved by modifying the mixing between fuel and oxidizer as well as the split between combustion and dilution air.

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Section: Introductionmentioning

confidence: 99%

Emission Modeling of an Interturbine Burner Based on Flameless Combustion

et al. 2018

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“…The combustor can then be partitioned in separate soot production and oxidation regions that exhibit different degrees of micro-mixing rates and residence times. In the context of kinetic post-processing, the ISRN equations can be decoupled from the calculation of the flow and mixing fields, consistently with other methods using ideal reactors (e.g., [22]). Unlike ideal reactors, however, unmixedness can be directly taken into account via the scalar dissipation rate and the mixture fraction probability density function (PDF).…”

Section: Gtp-20-1394 3 Gkantonasmentioning

confidence: 99%

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

Gkantonas

Foale

Giusti

et al. 2020

Journal of Engineering for Gas Turbines and Power

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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.

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“…The use and development of CRNs have been done both in manual (21)(22)(23) and automated forms (24)(25)(26) . Both approaches have shown good results with respect to predicting emissions.…”

Section: Chemical Kinetics Under the Fc Regimementioning

confidence: 99%

Effects of chemical reaction mechanism and NO_x formation pathways on an inter-turbine burner

Perpignan

Rao

2019

Aeronaut. j.

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One of the main challenges of future aircraft engines is to achieve low pollutant emissions while maintaining high combustion efficiencies and operability. The Flameless Combustion (FC) regime is pointed as one of the promising solutions due to its well-distributed reaction zones that yield low NOx emissions and oscillations. A dual-combustor configuration potentially facilitates the attainment of FC in the Inter-Turbine Burner (ITB). The development of such burner is dependent on knowledge regarding NOx formation and the parameters affecting it. It is known from the literature that the NOx formation mechanisms are different in FC. Therefore, in an attempt to clarify some of the mechanisms involved in NOx formation at relevant conditions, a chemical reactor network model developed to represent the ITB is explored. The role of prompt NOx was previously shown to be dominant at relatively low inlet temperatures and atmospheric pressure. In order to check these findings, five chemical reaction mechanisms were employed. All of them overpredicted NOx emissions and the overprediction is likely to be caused by the prompt NOx subset implemented in these mechanisms. Higher reactants temperatures and operational pressures were also investigated. Overall NOx emissions increased with temperature and the NOx peak moved to lower equivalence ratios. Operational pressure changed the emissions trend with global equivalence ratio. Leaner conditions had behaviour similar to that of conventional combustors (increase in NOx), while NOx dropped with further increase in equivalence ratio due to suppression of the prompt NOx production, as well as an increase in NO reburning. These trends highlight the differences between the emission behaviour of the ITB with those of a conventional combustion system.

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Analysis of high pressure premixed flames using Equivalent Reactor Networks for predicting NOx emissions

Cited by 30 publications

References 17 publications

Emission Modeling of an Interturbine Burner Based on Flameless Combustion

Emission Modeling of an Interturbine Burner Based on Flameless Combustion

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

Effects of chemical reaction mechanism and NO_x formation pathways on an inter-turbine burner

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Analysis of high pressure premixed flames using Equivalent Reactor Networks for predicting NOx emissions

Cited by 30 publications

References 17 publications

Emission Modeling of an Interturbine Burner Based on Flameless Combustion

Emission Modeling of an Interturbine Burner Based on Flameless Combustion

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

Effects of chemical reaction mechanism and NOx formation pathways on an inter-turbine burner

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Product

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Effects of chemical reaction mechanism and NO_x formation pathways on an inter-turbine burner