Jeudi 24 octobre à 14h, salle 357 ; IUSTI
Abstract: Carbonaceous soot particles have been known to be harmful to human health and a major climate forcer due to their light absorbing ability. Understanding the mechanisms of soot formation and developing reliable and robust soot models are essential to design efficient and clean combustion systems. Thermal radiation is often the dominant heat transfer mode in both turbulent and laminar flames and is strongly coupled with soot formation through the highly nonlinear dependence of soot kinetics on temperature and large absorption cross section of soot particles. Significant progress has been made in modelling soot formation, thermal radiation transfer, and turbulence radiation interaction in hydrocarbon flames over the last three decades. However, the optically thin approximation (OTA) has still been used to simplify thermal radiation transfer modelling and turbulence radiation interaction (TRI) has often been neglected in soot formation modelling in turbulent flames without proper justification.
In this presentation, soot models developed for laminar and laboratory scale turbulent jet diffusion flames, non-gray radiative heat transfer models, and turbulence radiation interaction models are reviewed. Mechanisms of soot formation and some important properties of soot are also briefly discussed. The aim of this review is to highlight the importance of thermal radiation heat transfer in both laminar and turbulent diffusion flames and TRI in turbulent jet diffusion flames. Use of the optically thin approximation is often not justified even in laminar diffusion flames. This is particularly true in diffusion flames at elevated pressures or microgravity. Although the prediction of soot in both laminar and turbulent flames is primarily influenced by soot kinetic model, it is also significantly affected by aerosol dynamic model, thermal radiation heat transfer model, and turbulence radiation interaction model. It is important to accurately model soot aerosol dynamics and non-gray thermal radiation transfer in laminar diffusion flames and additionally to adequately model TRI in turbulent flames for the purpose of validating reaction mechanisms and soot models.