Three-dimensional Linear Eddy Modeling of a Turbulent Lifted Hydrogen Jet Flame in a Vitiated Co-flow

Abstract

A new methodology for modeling and simulation of reactive flows is reported in which a 3D formulation of the Linear Eddy Model (LEM3D) is used as a post-processing tool for an initial RANS simulation. In this hybrid approach, LEM3D complements RANS with unsteadiness and small-scale resolution in a computationally efficient manner. To demonstrate the RANS-LEM3D model, the hybrid model is applied to a lifted turbulent N 2 -diluted hydrogen jet flame in a vitiated co-flow of hot products from lean H 2 /air combustion. In the present modeling approach, mean-flow information from RANS provides model input to LEM3D, which returns the scalar statistics needed for more accurate mixing and reaction calculations. Flame lift-off heights and flame structure are investigated

Dimensional Decomposition of Turbulent Reacting Flows

“…The LEM3D code has previously been applied to the Berkeley vitiated co-flow burner by Grøvdal et al (2018Grøvdal et al ( , 2020. In these studies, the LEM3D simulations showed good agreement with experimental data by Cabra et al (2002) in the far field, but the current implementation did not yield a lift-off height of the hydrogen jet flame of the burner in accordance with the experiments.…”

“…The LEM3D model has previously been described in detail by Sannan et al (2013), Weydahl (2010), and Grøvdal et al (2018Grøvdal et al ( , 2020. In LEM3D, three orthogonally intersecting arrays of 1D LEM domains are coupled so as to capture the 3D character of fluid trajectories.…”

“…One aim of the present paper is to gain a deeper understanding of the previously observed artifact and to assess its implications. Since the previous studies of a turbulent flame using LEM3D dealt with a composite flow configuration (Grøvdal et al 2018(Grøvdal et al , 2020, i.e., the lifted hydrogen jet flame of Berkeley's vitiated co-flow burner (Cabra et al 2002), we here first consider the simple configuration of a freely propagating flame to validate the diffusion and chemical kinetics implementation of the code.…”