NUMERICAL PREDICTION OF FLAME IMAGES IN THE VISIBLE SPECTRUM RANGE

In this paper a numerical technique is presented to predict the image of a free flame in the visible spectrum range from the computational r esults obtained with a fluid flow and combustion code. The numerical t echnique is composed of two submodels. The first one is a mathematical model based on the solution of the time-averaged form of the conserva tion equations for mass, momentum and energy. The output results are u sed as input data for the second submodel which is able to predict the flame image/brightness. This submodel is based on the integration of the radiative heat transfer equation along selected directions. The ba sic assumption of this submodel is that radiation is mainly due to soo t in the visible range of the spectrum. The model was applied to a tur bulent propane free flame for which experimental temperature measureme nts and digitized flame images were available. The predicted temperatu res are in reasonable agreement with the experimental data, and the sh ape of the predicted flame image is qualitatively similar to that of t he digitized flame image. Overall, the model proved to be a useful eng ineering predictive tool for numerical visualization of sooty flames.