Assessment of the Evolution Equation Modelling approach for three-dimensional expanding wrinkled premixed flames

Abstract

. Assessment of the Evolution Equation Modelling approach for threedimensional expanding wrinkled premixed flames. Combustion and Flame, Elsevier, 2012, 159 (5), pp.1932-1948. <10.1016/j.combustflame.2011 AbstractDirect Numerical Simulations (DNS), Evolution Equation Modelling (EEM) and Experimental results from the literature (EXP) are presented and analyzed for an expanding propane/air flame. DNS results are obtained thanks to the in-house finite-difference code HAllegro. Computed (DNS/EEM) and measured (EXP) equivalent radii R P and R S , mean stretch k and consumption velocity S C , as well as sample front shapes, are compared using to the same post-processing methodology. Small perturbations in the EEM input parameters induce comparatively small shifts in the compared results, showing the robustness of the approach. When slightly adapting only one O(1) parameter for the EEM strategy (the effective turbulent forcing amplitude felt by the flame), DNS and EEM show quite fair agreement one with the other and also with EXP, except for one of the experiments at early times. In the context of expanding flames, this validated EEM methodology can constitute a reliable tool to compute realisticly large sized flames.

Reynolds number scaling of burning rates in spherical turbulent premixed flames

“…This patching strategy does not compromise the evolution of turbulence during decay as shown by previous studies (Albin 2010; Albin & D'Angelo 2012) and all turbulence statistics are consistent with the theory of decaying turbulence. In particular, the decay of the turbulent kinetic energy follows the power law (Batchelor & Townsend 1948 a , b ; Sinhuber, Bodenschatz & Bewley 2015), where is the virtual origin, the turbulent kinetic energy at and is the decay exponent.…”

Simulation of Spherically Expanding Turbulent Premixed Flames

“…The DNS studies were initially aimed to address ignition related issues (Baum and Poinsot, 1995;Poinsot et al, 1995) using a single irreversible reaction in two-dimensional turbulence. Some of these limitations were relaxed in later DNS studies on spherical flames (Albin and D'Angelo, 2012;Jenkins and Cant, 2002;Jenkins et al, 2006;Kaminski et al, 2000;Klein et al, 2006Klein et al, , 2008Thévenin, 2005;Thévenin et al, 2002;van Oijen et al, 2005) and these studies predominantly addressed flame surface density (FSD)-related modeling issues. LES, in which the large-energy-containing scales are resolved but the flame front is modeled, has recently been used to study ignition and propagation of turbulent spherical flames (Colin and Truffin, 2011;Fureby, 2005;Lecocq et al, 1510 I. AHMED AND N. SWAMINATHAN 2011; Nwagwe et al, 2000;Tabor and Weller, 2004).…”

Computational Assessment of Curvatures and Principal Directions of Implicit Surfaces from 3D Scalar Data

“…The interface is then a 3D surface defined as the isocontour φ(x, y, z) = φ 0 = cst. Some geometrical properties like normals n and mean curvatures κ H are deduced from φ using formulas (1) and (2):…”

“…The flame images are obtained from Direct Numerical Simulations using the H-allegro in-house software [1] on a supercomputing infrastructure (PRACE).…”

“…For instance, local curvatures can modify combustion speed [1,8,9,38], surface tension [4] and evaporation speed [7]. Accurate methods for determining curvatures can then be of paramount importance for flow analysis.…”