HydrogEn combuSTion In Aero engines

Deliverables

Development and validation of low order models for these transient phenomena and prediction of system thermoacoustic stability maps

The deliverable is performed by using a novel low-order acoustic-network modelling (LOM) tool, study thermoacoustic combustion instabilities and acoustic perturbations in complex realistic configurations based on “state-space” framework and “generalised modal expansions” named STORM.

Benchmark computations

This deliverable includes preliminary comparative analysis of existing benchmark problems for nonreactive and reactive conditions characterized by a flowgeometry complexity similar to the present model combustion chamber

Hydrogen multipoint injector designs for low TRL testing

Design studies will be carried out on novel fuel injection technologies based on distributed/multi-point injections, which have potential to control NOx production better than conventional rich burn or lean burn injectors. Given the higher flame speed and reduced ignition delay times for H2, premixed systems carry significant risk of flashback and auto-ignition, and for aero applications ensuring safety is more critical compared to ultra-low NOx levels capable with premixed systems. Therefore, the focus will be mainly on lean direct injection concepts. Design studies will also investigate complementary changes required to combustor to maximise the potential of novel injection technology. Design studies will initially be performed with current modelling capability followed by application of improved flamelet based modelling capability.

Validated H2 combustion modelling method with PRECISE-UNS

The new modelling strategies developed in deliverables D1.10 et D.1.12 will be implemented and validated into the Rolls-Royce CFD code PRECISE-UNS through interactions with RRUK and RRD.

Completed design, fabrication, and commissioning of premixed, partially premixed, and non-premixed LSB.

This deliverable details the design fabrication and delivering of LSB test bench for different kinds of configurations premixed partially premixed and non premixed flames

Validation of the Safran numerical methodology for H2/air combustion against two measured injectors configurations

The study will consider two injectors, experimentally investigated in T2.2.1 (strut injector) and T1.1.1 (rich concept). Both experimental measurements will be conducted on academic test benches allowing experimental measurements but not fully representative of aircraft combustion chamber geometries and operating conditions. The deliverable will validate the ability of the numerical methodology, developed at Safran, to capture the flame structure, quenching limits and NOx emissions on the test bench configuration for both injectors.

Experimental data set from lab scale test campaign

A lab scale experiment will be devised and performed to characterise H2air flame at atmospheric conditions Advanced diagnostics will be applied to derive a data set for validating CFD methods

LES-based turbulent combustion models for high-pressure H2 combustion

The subtask is devoted to the evaluation of LES methodologies for H2 combustion simulation up to high pressure (P=30 bars) with a focus also on rich burn conditions (equivalence ratio Φ between 1.5 and 2.5). Models considered are more especially the TFM and the FGM with presumed PDF closure.

Non-reactive simulations of academic combustor

The deliverable focuses on the use of the experiments conducted by LUH in Subtask 2.1.1 (D2.5) to identify and validate the appropriate numerical models to predict H2 related combustion. This will allow the design of the concept for the H2 feed to the setup of the LUH combustion chamber.

Conception of the injection systems and the high-pressure burner

An adaptation of an available high-pressure burner will be performed for implementing the new injection systems. The injection systems will be assimilated to alternative-wedge struts which can generate streamwise vortices for fuel/air mixing enhancement. Several kinds of architectures will be examined to study the effects of the streamwise vortex arrangements such as vortex strength, counter or co-rotating vortex arrangement on the mixing characteristics as well as the combustion efficiency. For the experiments, each strut could generate several vortices (up to 8) in a spanwise row configuration. Gaseous Hydrogen will be injected parallel to the mainstream direction directly in the core region of each streamwise vortex through a series of small orifices. The injection system will be mounted in a water-steel pressure housing with four optical accesses. Pressure will be adjusted between 0.1 to 0.4 MPa.

Experimental data set from reacting measurements

The deliverable pursues the study performed in D2.5 to reactive flows by analysing the temperature distribution. Local temperatures will be measured using thermocouples. The potential of additional measurement techniques, such as the Rayleigh-Scattering will also be evaluated. NOx concentrations will also be measured using Fourier transformed infrared spectroscopy. The measurement of combustion radicals, such as OH* is also possible. LIF can provide a 1- or 2-dimensional, qualitative concentration field.

Experimental characterization and numerical simulation (LES) of stable operating conditions with large noise emission and thermoacoustic instability

The objective of this deliverable is to characterize transient phenomena in a single burner, swirled, test rig developed at INPT and instrumented for optical diagnostics and acoustic characterization. Experiments and LES (coordinated with CERFACS) will be used jointly for all these phenomena.

A non-adiabatic turbulent combustion model which predicts NOx formation

A LES turbulent combustion model for non-adiabatic stratified flames compatible with the virtual chemistry formalism will be developed. The challenges are to handle the interactions of turbulent scales with both the very fast chemistry of the hydrogen flame front and the slowest formation NOx. The numerical development will be validated by computing target configurations of turbulent H2-Air flame experimented within the project.

Feasibility study on semi academic/industrial burner (e.g. PRECCINSTA)

This deliverable synthesizes the feasibility of the LBM methodology developed in deliverable D1.7 on semi academic/industrial (like PRECCINSTA) for evaluating combustion instabilities.

Combustion instability study for an anchored Bunsen flame

This deliverable reports combustion instabilities studies for academic elementary test cases (Flame’s answer to acoustic, FTF), boundary conditions implementation and for a Bunsen flame anchored at a section change (2D then 3D). This study is performed numerically by using Lattice-Boltzmann methodologies.

Emission index of several flames of interest

The deliverable reports quantitative measurements of NO in several hydrogen-air flames by usig advanced diagnostics. These diagnostics will be used to analyse the NOx formation processes.

DNS database of hydrogen combustion in stratified conditions

The proposed study will be conducted on the basis of high-fidelity simulations (DNS/LES) conducted with the CREAMS computational solver, coupled to the CVODE solver and to the EGLIB library.

Data management plan

Plan detailing data management procedures to be followed by all partners, relevance of data with and limitation to the research purposes of the project, description of the technical and organisational measures implemented to safeguard the rights and freedoms of the data subjects/research participants. (Linked with all projects tasks but especially task 4.2)

Experimental data set from isothermal measurements

This study will design a fuel nozzle and identify a suitable combustion concept. Investigation of three flame types which differ in the position of the H2 injection: premixed, partially premixed and non-premixed. This first deliverable focuses on the analysis of the non-reactive flow of identified concept using a velocity field determined using seeded PIV.

Hydrogen injector design definition

Adaptation of a RQL injector for H2 an existing combustor (developed for kerosene) and optimized for H2 combustion. The focus on the CFD based studies will be on NOx emissions and stability. The study will also focus on lean burn systems without dilution ports. It is expected that due to the very short ignition delays times, it is not possible to premix H2 with air, so concepts have to be developed where the mixing of fuel and air takes place within the combustion chamber. A possible concept is FLOX, where air and fuel are injected with high velocity leading to high mixing rates and the high velocities to prevent immediate combustion.

Flame properties and NO formation

The experimental description of aerodynamics and the flame structure will be performed. The aerodynamic field downstream from the injector will be characterized with velocity measurements performed with the PIV laser diagnostic. Spatial distribution of fuel concentration will be obtained from organic tracer-PLIF measurements. OH-PLIF will be used to determine the reaction zones downstream from the injector. Measurements of NO concentration will be performed using the PLIF-NO diagnostic. An effort will be done to combine the diagnostics for obtaining detailed correlation on the different mechanisms governing the stability, the efficient and the NO formation. All the laser diagnostics are available.

Test matrix definition for TUM test

This deliverable will define the test matrix for TUM test performed in D3.7 to evaluate the capabilities of injectors.

Development of the flamelet solver and validation of the extended flamelet manifolds

This deliverable will describe the generalized multi-regime flamelet solver developed specifically to account for differential diffusion and curvature effects in H2 combustion. It will also discuss the validation of the resulting extended flamelet manifold by a priori analysis on DNS benchmark data attained within this project (T1.3.1). .

Low-order modelling of the ignition process of rich H2/air mixtures

The TFM and a hybrid TFM+FGM model will be used to perform high-fidelity investigations of the ignition process. The models will be developed starting from the baseline version available in the industrial CFD code adopted by AVIO. A CFD-based low-order model originally developed by UCAM and recently reconsidered by UNIFI will be adapted to hydrogen to draw out ignition probability maps leveraging the detailed investigations carried out with LES.

Set-up of online community engagement tool

A dedicated sharepoint (or equivalent) area will be set up so that members of the HESTIA advisory Board will have access to documentation and data specifically tailored to them.

Measurement of flame structures for various injection modes

This deliverable contains the report on the measurements and the evaluation performed on hydrogen flames using LEAF burner, including various injection modes and RQL concepts, at atmospheric conditions.

Virtual scheme for H2/air combustion which includes all NOx pathway

This deliverable deals with the development of an accurate highly reduced chemical scheme based on the virtual chemistry method. The virtual scheme will be able to reproduce both prompt and thermal NO pathways in a non-adiabatic environment. For that purpose, kinetics rates constants of virtual elementary reactions will be optimised through machine-learning algorithms. The numerical development will be validated by computing target configurations of turbulent H2-Air flame experimented within the project.

Detailed analysis of flame shapes and stabilization mechanisms.

This deliverable reports the detailed analysis of flame shapes and stabilization mechanisms realized with Low-Swirl burner developed in D1.3. Simultaneous measurements of OH PLIF, Stereoscopic PIV, and phosphor thermometry will be performed.

Assessment of CFD predictive capability based on elevated pressure testing

This deliverable will extend to hydrogen combustion the FlaRe (Flamelets Revised for consistencies) modelling framework. UCAM will apply and test the model at atmospheric pressure and then at elevated temperature and pressure conditions. The test cases relevant to high pressure and temperature condition will be found in the literature.

HESTIA public website

A public website will be created to allow dissemination and communication activities to be performed towards the general public

Publications

Optimisation of a Hydrogen-Fuelled Parametric Strut Injector Using an Automated Workflow CFD Method

Author(s): Treleaven, Nicholas; Fournier, Guillaume; Leparoux, Julien; Mercier, Renaud
Published in: Volume 3B: Combustion, Fuels, and Emissions, 2024, ISSN 7918-8795
Publisher: ASME
DOI: 10.5281/ZENODO.12733416

"High-frequency thermo-acoustic instability in a dual swirl H<mml:math xmlns:mml=""http://www.w3.org/1998/Math/MathML"" altimg=""si2.svg"" display=""inline"" id=""d1e649""><mml:msub><mml:mrow/><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math> burner"

Author(s): H. Paniez, S. Marragou, H. Magnes, T. Schuller
Published in: Proceedings of the Combustion Institute, Issue 40, 2025, ISSN 1540-7489
Publisher: Elsevier BV
DOI: 10.1016/J.PROCI.2024.105679

Flame characteristics and lift-off dependencies of flames stabilized on a multi hydrogen jet in swirled crossflow burner

Author(s): Lars Koch, Julian Bajrami, Friedrich Dinkelacker
Published in: Proceedings of the Combustion Institute, Issue 41, 2025, ISSN 1540-7489
Publisher: Elsevier BV
DOI: 10.1016/J.PROCI.2025.105878

"Role of hydrodynamic instabilities in high-frequency transverse thermoacoustic instabilities in a dual-swirl H<mml:math xmlns:mml=""http://www.w3.org/1998/Math/MathML"" altimg=""si10.svg"" display=""inline"" id=""d1e407""><mml:msub><mml:mrow/><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math> burner"

Author(s): Hyebin Kang, Hugo Paniez, Thierry Schuller
Published in: Proceedings of the Combustion Institute, Issue 41, 2025, ISSN 1540-7489
Publisher: Elsevier BV
DOI: 10.1016/J.PROCI.2025.105837

Intrinsic thermoacoustic instability in hydrogen enriched partially premixed flames

Author(s): Ankit D. Kumar, James C. Massey, Preethi Rajendram Soundararajan, Isaac Boxx, Nedunchezhian Swaminathan
Published in: Physics of Fluids, Issue 37, 2025, ISSN 1070-6631
Publisher: AIP Publishing
DOI: 10.1063/5.0258444

Deliverables

Publications

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