Extensions of the SSTF model for applications in which density depends on temperature

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Moreau, Vincent
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This paper is devoted to premixed combustion modelling in turbulent flow. First, we briefly give the main features of the SSTF model and its shortcomings, more extensively developped in a former paper. Then, we carefully describe some improvement of the model. The turbulent flame velocity is based on the observed self-similarity of the turbulent flame and uses the local flame brush width as a fundamental parameter, which must be retreived. We derive more rigorously the way density variations have to be taken into account in the width retreiving fuction. We reformulate the diffusion term as a classical flux divergence. We enforce the compatibility of the model for the limit of small turbulence. We include a contracting effect of the source term, allowing to give a stationnary monodimensional asymptotic solution with finite width. We also include in a preliminary form, a stretch factor, which proves to be useful for controling the flame behaviour close to the flame holder and near the walls. The model implementation in the StarCD CFD code is then tested on three different flame configuration. Finally we shortly discuss the model improvements and the simulation results.
turbulent flow , CFD , combustion modeling , self similar turbulent flame (SSTF)