Evaluation of Modified Two-Equation Turbulence Model for Nonpremixed Jet Diffusion Flame

摘要

The topic of this work is the numerical simulation of a turbulent diffusion jet flame fueled with a mixture of CH_4, H_2, and N_2. Simulations have been investigated with different two-equation turbulence models to improve prediction of jet flow-fields. The calculations are validated against existing experimental data provided by Raman and laser Doppler anemometry (LDA) and Laser Doppler Velocimetry (LDV). In particular, a comparison of three two-equation turbulence models and their influence on combustion process is presented: the Pope correction, the standard k-e model and realizable k-ε. For combustion modeling EDC model with a 25-step reaction is considered. The numerical results for mean velocity components, temperature, and major chemical species are presented and compared with the experimental data. The additional goal of the work is to investigate the capabilities of the used turbulence models in proper predicting of the round jet spreading in a non-premixed jet flame. This simple geometry allows for reliable flow simulations. Regarding the basic test case under consideration, the results obtained by the EDC model with modified standard k-ε model with the Pope correction are in sufficient agreement with experimental data. The calculations were performed using FLUENT 2D and 3D solver. The Pope correction has been applied via UDF. The advantages and disadvantages of the models are discussed in detail in relationship to the results.