Análise da influência de modelos de turbulência e de cinética química na simulação de uma chama de hidrogênio

Abstract

In an economic scenario characterized by the increasing adoption of hydrogen gas in the global energy matrix as one of the strategies to mitigate the advances of the climate crisis related to the use of fossil fuels, Brazil emerges as a potential large-scale producer of this energy carrier. The computational analysis of a diffusive hydrogen flame proves to be essential for the development and optimization of projects. Among the various parameters involved in a computational combustion simulation, turbulence and chemical kinetics models are crucial for predicting the flame behavior concerning species emission rates and average temperature. This work aims to analyze the influence of chemical kinetics models varying in complexity and turbulence models employing different mathematical approaches using the ANSYS-Fluent software to predict the axial profile of emissions and temperature in a turbulent diffusive hydrogen gas flame, H2. The GRI Mech 3.0 and Conaire et al. (2004) mechanisms were compared along with the k −ω SST and standard k −ε turbulence models. An unstructured hexaedral mesh was used for the simulations. For both mechanisms, the results for the turbulence models indicate mixed performances, with the k −ω SST showing better results in general for O2 curves and for H2O and temperature curves normalized from the z/d = 100 point. The k−ε model had a better overall fit for N2, OH curves. In general, all applied configurations overestimated the values of species generation/consumption and temperature