Position details

Study of spark plug ignition systems: from spark to flame
Training › Computational Fluid Dynamics - Combustion

Required Education / Niveau requis

Master or engineering school

From / Date de début

First semester 2013

Duration / Durée

6 months

Context / Contexte

Spark ignition engines, either for the  automobile or aeronautical industry, need a reliable and performant ignition system. Although new technologies are today under development, such as laser ignition, the electric spark plug stays, and will stay for a number of years,  the most used technique. Although an old technique, it has little evolved since it was satisfactory as is,  and consequently it has been little studied. Therefore, the mechanisms associated to the spark ignition process, including very different physics, from electricity to plasma physics and turbulent combustion, are not fully known and understood. As the search for performance and innovation is becoming more and more crucial to increase the market share, it is now relevant to develop new spark plug ignition systems. In this approach, a first step is to improve the knowledge of such systems: this is the objective of the FAMAC project,  funded by ANR abd coordinated by Continental.

Description / Description

The ignition sequence starts with the electric discharge, leading to the formation of an electric arc, and a very high gas temperature, reaching the state of a plasma. A cooling phase follows under the effect of diffusion / radiation, during which combustion chemistry is activated.

In the framework of the FAMAC project, CERFACS  will perform the simulation od an ignition sequence with a spark plug, from the end of the  plasma phase until the establishment of a flame kernel,  in  a realistic  ambiant flow, ie. with turbulence. A first difficulty is to determine the state of the gas at the end of this plasma phase. To do that, it is proposed in this study to use non-equilibrium thermodynamics and thermochemistry to calculate the state of the gas issued from the plasma and their evolution during ignition, together with the exact conditions in which combustion starts. 0D thermochemistry computations will be realised with the code  CANTERA. The system will be  considered adiabatic, but heat exchanges with surrounding gases will be a posteriori evaluated. Steps will be the following:

- Bibliography study and discussion with the laboratoire Laplace (Toulouse), specialist of plasmas.

- Learning of CANTERA.

- Development and integration of data / modules for the calculation of non-equilibrium thermochemistry in CANTERA.

-  0D simulations in conditions representative of a spark plug.

- Determination of the thermodynamic state and chemical composition  of gases at the beginning of the combustion phase.

- Evaluation of heat loss by diffusion and thermal radiation .

Contacts / Contacts

Name: Vermorel Olivier
Phone: +33 (0)5 61 19 30 33
Fax: +33 (0)5 61 19 30 30
Email: vermorel@cerfacs.fr

Name: Cuenot Bénédicte
Phone: 05 61 19 30 44
Fax: 05 61 19 30 00
Email: cuenot@cerfacs.fr

Salary / Rémunération

580 Euros/mois