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Emissions SooT ModEl

Periodic Reporting for period 1 - ESTiMatE (Emissions SooT ModEl)

Reporting period: 2018-11-01 to 2020-04-30

ESTiMatE addresses the fundamental issue of soot formation for kerosene-type fuels under lean burn conditions for Very High Bypass Ratio engines. While at full power conditions soot emissions of lean burn systems are bound to be low, at intermediate conditions particulate formation can be significant.

The project ESTiMatE is dedicated to the development of advance soot models and its application in combustion simulations for the prediction of soot formation from chemistry oxidation to particle formation at conditions of relevance for aeroengines.

ESTiMatE has defined the following specific objectives:

1) Identification of the main precursors and polycyclic aromatic hydrocarbons (PAHs) for soot formation from the analysis of chemical kinetics of kerosene-like surrogates.
2) Identification of chemical paths for soot formation from precursors and PAHs.
3) Generation of detailed and reduced chemical kinetics for fuel oxidation that also account for soot chemistry.
4) Development of particle size distribution models to represent the dynamics of soot.
5) Integration of the developed chemical kinetics and soot models into different turbulent combustion models.
6) Development of a primary breakup model for air blast injectors based on high-fidelity numerical simulations.
7) Development of reference experiments for combustion from laminar to turbulent conditions to generate specific data for model development and validation.
8) Implementation of the different models into Rolls-Royce code PRECISE-UNS.
9) Assessment of models for the prediction of soot under conditions relevant to aero engine combustors.
The progress made at month 9 of the project show that all the technical activities have already started. During the first month, the specification of a kerosene fuel surrogate was conducted by USTUT and KIT, and from this point, the experimental campaigns and the generation of a reaction mechanism started. Experiments with the kerosene surrogate in a laminar counterflow flame configuration are in progress, while the designs of the low TRL turbulent test rigs are also finalized. The experimental campaign for the testing of swirl-stabilized and counterflow flames has also started. In parallel, the two proposed soot models, that is, the sectional method and the Extended Quadrature Method of Moments (EQMOM), were validated in laminar flame configurations and are being integrated in the CFD codes of the consortium to run simulations of turbulent flames. Finally, the numerical simulations required for the development of a phenomenological model for primary breakup of airblast atomizers has also started.
The project ESTiMatE is focused on the study of soot formation in aeronautical burners using advanced soot models for particle size distributions. The project results will shed some light into the influence of the combustion model and the treatment of turbulence chemistry interactions on the prediction capabilities of the soot models in terms of soot volume fraction, soot volume density and particle size distributions. The validation and assessment of the models comes from the definition of dedicated experiments with an increased level of complexity, going from pre-vaporized counterflow flames, kerosene spray flames up to single sector and full annular rigs. The project includes the development of a reaction mechanism for the fuel oxidation and soot precursors for a fuel surrogate, and the development of a phenomenological model for primary breakup of airblast atomizers. The impact of the project will be development of advanced software for pollutant formation that can be used with confidence to speed up the combustion design process.