Non-Premixed Filtered Tabulated Chemistry: Filtered Flame Modeling of Diffusion Flames

Pedro Javier Obando Vega,Axel Coussement,Amsini Sadiki,Alessandro Parente

doi:10.3390/fuels2020006

Pedro Javier Obando Vega, Axel Coussement + Show 2 more

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https://doi.org/10.3390/fuels2020006

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Abstract

The flame front filtering is a well-known strategy in turbulent premixed combustion. An extension of this approach for the non-premixed combustion context has been proposed by means of directly filtering counterflow diffusion flamelets. Promising results were obtained for the non-premixed filtered tabulated chemistry formalism on 1-D and 2-D unresolved counterflow flame configurations. The present paper demonstrates the soundness of this approach on a 3-D real laminar non-premixed coflow flame. The model results are compared against the direct filtering of the fully resolved laminar diffusion flame showing that the formalism adequately describes the underlying physics. The study reveals the importance of the one-dimensional counterflow flamelet hypothesis, so that the model activation under this condition is ensured by means of a flame sensor. The consistent coupling between the model and the flame sensor adequately retrieves the flame lift-off and satisfactorily predicts the profile extension due to the filtering process.

Highlights

An extension of this approach for the non-premixed combustion context has been proposed by means of directly filtering counterflow diffusion flamelets
The performance of the non-premixed filtered tabulated chemistry formulation coupled with the novel flame sensor is assessed, and good agreement with the reference solution is achieved
The present work assessed the capability of the non-premixed filtered tabulated chemistry formalism to adequately describe the filtered flame structure of a real laminar coflow diffusion flame

Summary

Introduction

An extension of this approach for the non-premixed combustion context has been proposed by means of directly filtering counterflow diffusion flamelets. Flamelet based methods assume thin flame structures with significantly smaller time scales compared to the flow Exploiting this feature, the chemistry description can be parametrized in terms of few controlling variables resulting in significant computational time reduction [2]. Within this framework, FGM (Flamelet Generated Manifold) [3] and FPI (Flamelet Prolongation of Intrinsic Low Dimensional Manifolds) [4], both initially developed for premixed and afterwards extended to non-premixed regime, as well as FPV (Flamelet/Progress Variable) [5,6] method for non-premixed regime are consolidated techniques. FGM is coupled with an ATF (Artificially Thickened Flame) [8] approach employing dynamic flame surface wrinkling, or oxy-flame combustion by means of FPV coupling with an stochastic fields methodology [9]

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