Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
Spray-flamelet approach by means of a monotonic cumulative mixture fraction variable
Submission Author:
Daniela Maionchi , MT
Co-Authors:
Daniela Maionchi, Fabio Santos, Josue Melguizo-Gavilanes
Presenter: Daniela Maionchi
doi://10.26678/ABCM.COBEM2017.COB17-1074
Abstract
The external structure of the spray-flamelet can be described using the Schvab-Zel’dovich-Liñan formulation. The mixture-fraction variable Z normally employed for the description of gaseous diffusion flames leads to non-monotonicity behavior for spray flames due to extra fuel supplied by vaporization of droplets distributed into the flow. Therefore, spray flames depend not only on Z and the scalar dissipation rate, but also on the spray source term. Since the mixture fraction is locally normal to the surface of stoichiometric mixture, its cumulative value, ZC =∫−∞ z Z(t)dt/ZCT, can also be considered as a coordinate variable that guarantees monotonicity. This new quantity includes spatial information about the whole mixture fraction due to gaseous phase and droplet vaporization. For pure gaseous flow, the well-established description in terms of Z is recovered. The spray-flamelet structure and the new equations of temperature and mass fractions in terms of ZC are derived. The proposed formulation is applied in a counterflow configuration. The numerical results are obtained for ethanol spray and presented for the temperature and mass fractions in terms of ZC. The accuracy of the results confirms the validity of the proposed formulation.
Keywords
counterflow diffusion flame, spray-flamelet, cumulative mixture fraction, monotonic variable
