Cerfacs Enter the world of high performance ...

You Tube Link : https://youtu.be/oN27Av51CkI

Abstract :

In the field of aeronautical propulsion, the current trend is to us lean or even very lean combustion regimes, in order to limit pollutant emissions. However, this is a major technological challenge, since lean combustion is prone to instabilities and does not guarantee the ignition and re-ignition capabilities at altitude required for certification.

An emerging solution, applicable to a wide range of configurations, to enable ignition and combustion stabilization in lean regimes is the use of low-energy electrical discharges near the flame. Among the different types of discharges available, the Nanosecond Repetitively Pulsed (NRP) discharges are particularly interesting. However, despite their proven effectiveness, the fundamental mechanisms of the interaction between the combustion and the plasma generated by the discharge are not well understood. Moreover, there is no operational numerical tool to evaluate the performance of NRP discharges in practical configurations.

The objective of this thesis is twofold. The first one is to develop a low-temperature plasma code able to model the plasma phase. This task is done in the parallel and unstructured code AVIP which shares the data structure of the combustion code AVBP developed at CERFACS. In a second step, this modeling will allow to study in detail the mechanisms of interactions between the plasma and a flame in point-to-point configurations. For this purpose, a detailed chemistry for plasma assisted combustion has been first developed and validated against experimental data in laboratory configurations. The detailed chemistry being too expensive for multi-dimensional simulations, a reduction step has been performed and a phenomenological model has been proposed. The reduced kinetic mechanism is finally used in a multi-dimensional calculation, by coupling AVBP and AVIP codes, to study the effects of NRP discharges in air and for the ignition of a methane-air mixture.

Keywords : Plasma; Combustion; NRP discharges; Simulation; Chemistry; Methane

Jury :

Arnaud Bultel – Maître de Conférences – CORIA – Referee

Deanna Lacoste – Associate Professor – KAUST – Referee

Anne Bourdon – Professor – LPP – Member

Benoît Fiorina – Professor – EM2C – Member

Fabien Tholin Researcher – ONERA – Member

Bénédicte Cuenot Professor – CERFACS – Director

Olivier Vermorel Researcher – CERFACS – Invited