An efficient flamelet progress-variable method for modeling non-premixed flames in weak electric fields

• Published in: Computers & fluids Vol. 157; pp. 14 - 27
• Main Authors: Di Renzo, M., De Palma, P., de Tullio, M.D., Pascazio, G.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 03.11.2017; Elsevier BV
• Subjects: Charge transport; Chemi-ionization; Combustion chambers; Complexity; Computational efficiency; Computational fluid dynamics; Computer simulation; Electric fields; Flame structure; Flammability; Flammability limits; Fluid dynamics; Ionization; Low-Mach-number formulation; Mathematical models; Nonpremixed flames; Partially-premixed combustion; Simulation; Weak electric field; Partially-premixed combustion; Charge transport; Weak electric field; Low-Mach-number formulation; Chemi-ionization
• ISSN: 0045-7930; 1879-0747
• DOI: 10.1016/j.compfluid.2017.08.024

•A flamelet model for simulating flames interacting with electric fields is proposed.•The framework can handle various chemical mechanism and species transport models.•The model is able to reduce the computational cost of the simulation up to 40 times.•The model provides a good agreement with the results present in the literature. Combustion stabilization and enhancement of the flammability limits are mandatory objectives to improve nowadays combustion chambers. At this purpose, the use of an electric field in the flame region provides a solution which is, at the same time, easy to implement and effective to modify the flame structure. The present work describes an efficient flamelet progress-variable approach developed to model the fluid dynamics of flames immersed in an electric field. The main feature of this model is that it can use complex ionization mechanisms without increasing the computational cost of the simulation. The model is based on the assumption that the combustion process is not directly influenced by the electric field and has been tested using two chemi-ionization mechanisms of different complexity in order to examine its behavior with and without the presence of heavy anions in the mixture. Using a one- and a two-dimensional numerical test cases, the present approach has been able to reproduce all the major aspects encountered when a flame is subject to an imposed electric field and the main effects of the different chemical mechanisms. Moreover, the proposed model is shown to produce a large reduction in the computational cost, being able to shorten the time needed to perform a simulation up to 40 times.