Session: 04-29 Emissions hydrogen/ammonia II

Paper Number: 127585

127585 - Computational Cost Optimization of Hydrogen-Air Combustion for NOx Prediction 

The switch from fossil fuels to hydrogen represents a breakthrough path towards the decarbonization of the aeronautical sector. As far as the combustion chamber is concerned, this switch can impact significantly both the technologies employed and the design methodologies.

Over the last couple of decades, efforts on numerical simulations have been focused on kerosene-air mixtures, following the design needs towards more efficient aero-engines. However, hydrogen has very different characteristics such as a thinner and faster flame front, a lower density and a larger impact of differential diffusion. These properties challenge the current state of the art of numerical methods that must be re-evaluated in terms of accuracy and computational cost for aeronautical applications.

Nowadays, high-fidelity simulations, more specifically Large Eddy Simulations (LES), are majorly employed in technical literature to investigate hydrogen combustion. However, these simulations can be  computationally intensive and too costly with respect to the industrial constraints.

In this work, a study to reduce the time-to-solution in LES is performed. The selected configuration is a two-staged swirled combustor. The reference LES numerical setup includes a detailed chemical description by using a 21-species chemical scheme (including NOx) and the thickened flame model to handle turbulent combustion. From this, different numerical combinations are investigated for each phase of the simulation (from non-reactive flow to flame stabilisation) as well in terms of chemistry description to minimise the LES return time. All in all, the optimisations carried-out determine different degrees of reduction in terms of computational cost with respect to the reference setup, while the experimental flame topology is fairly well retrieved. The general trend for NOx emissions at the burner outlet is as well correctly captured, even if the chosen methodologies differ on the absolute values.

Presenting Author: Quentin Buisson CNRS EM2C - UPR 288

Presenting Author Biography: To be done

Authors:

Quentin Buisson CNRS EM2C - UPR 288
Julien Leparoux Safran Tech
Stefano Puggelli Safran Tech
Maxime Leroy CNRS EM2C - UPR 288
Clément Mirat CNRS EM2C - UPR 288