Application of unstrained flamelet SGS closure for multi-regime premixed combustion

Large Eddy Simulation of a Bluff Body Stabilised Premixed Flame Using Flamelets

“…One such model was developed [23] and tested [24–26] in past studies and this model is briefly discussed next, along with the combustion modelling used for this study. The importance of transporting the SGS variance and the closure models used within its transport equation have been discussed in previous studies [11, 24] and the behaviour of the SGS variance in bluff body flames is discussed in [11]. …”

“…Various models have been proposed in past studies and are reviewed in [6–10]. Out of these models, the flamelet approach is the simplest one and it has been demonstrated recently that this approach can be used for capturing multi-regime turbulent premixed combustion; this was previously achieved by considering a bluff body stabilised turbulent premixed flame within a confined chamber [11]. …”

“…However, the specific focus of this work is to demonstrate, as a first step, that an unstrained flamelet model can accurately capture the stabilisation of flames far from blow-off conditions, along with the various flame and flow attributes of the bluff body stabilised open flame. This is achieved by simulating the bluff body stabilised methane-air flames investigated experimentally in [1], which differ substantially from the flames considered in the study by Langella et al [11]. The experimental flames investigated in [11] were confined within a rectangular duct that contained a turbulence generator upstream of the bluff body base.…”

“…This is achieved by simulating the bluff body stabilised methane-air flames investigated experimentally in [1], which differ substantially from the flames considered in the study by Langella et al [11]. The experimental flames investigated in [11] were confined within a rectangular duct that contained a turbulence generator upstream of the bluff body base. Thus, the turbulence experienced by those flames came from both incoming and shear generated turbulence [12–16], whereas the flames investigated by Kariuki et al [1] experienced mostly shear driven turbulence, since a turbulence generator was absent in the burner configuration.…”

“…In light of the results presented by Langella et al [11], the aim of this study is to test the applicability of the unstrained premixed flamelet closure as SGS combustion closure for modelling the open bluff body stabilised turbulent premixed flame that is furthest from blow-off. In addition, this study highlights the differences in the spatial evolution of the shear layers and the flame brush for the open flame studied here and for confined bluff body stabilised flames.…”