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

Abstract

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 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.

Reactive Molecular Dynamics Investigation of Toluene Oxidation under Electrostatic Fields: Effect of the Modeling of Local Charge Distribution

“…In recent years, there has been an increased interest in the evaluation of the effect of electrostatic fields on flames. Experiments − and numerical simulations − have highlighted important effects on emissions, flame shape, and stability. The effect of electric fields was mainly justified in terms of displacement of the ionic species arising from the electric forces, the so-called ionic wind .…”

A Comprehensive Review of the Influence of Electric Field on Flame Characteristics

“…If the drift speed of electrons is taken into account, it will further increase the burden on the computer [49]. Therefore, it is necessary to simplify certain chemical effects in the three-dimensional model [50]. For example, it is difficult to accurately describe the multi-component transport coefficient in a multi-dimensional problem.…”

Direct numerical simulation of a turbulent methane/air flame impinged by a sub-breakdown electric field

“…In this study, the numerical stiffness of the problem was palliated by deploying a reduced chemical mechanism and an implicit iterative method. Other studies related to two-dimensional configurations were carried out on lifted planar-jet flames [24][25][26]. These studies utilized Flamelet Progress Variable (FPV) models modified to describe the combustion chemiionization chemistry while retaining an acceptable computational cost.…”