Computational Study of The Stability of Turbulent Hydrogen Jet Flames with Methane Addition

Abstract

As the world predominately relies on fossil fuels to meet the current energy demands, the increasing consumption of it negatively impacts the environment. Thus, among constant search of a cleaner alternative fuel, hydrogen offers the greatest potential benefits in terms of energy supply and environmental impacts. However, hydrogen combustion is challenged by the difficulties in its production, storage, and end-use. Therefore, another method to enhance hydrogen combustion is to use hydrogen with methane addition as fuel. This study presents the effect of methane addition on the stability of hydrogen-methane flames by performing numerical analysis. In this study, the stability parameters such as lift-off height, lift-off velocity and blow-out velocity of hydrogen-methane jet flames were tested in three different mixing configurations. The first was to inject pure methane and pure hydrogen flames to form a jet flame. The second was to premix hydrogen and methane to form a jet flame. The third was to inject methane as an annular jet with hydrogen as the centre. All three different mixing configurations shows different results in terms of its stability parameters. From the first configuration, the lift-off height of pure methane is higher than pure hydrogen. From the second configuration, as methane concentration increases, the lift-off height increases but the lift-off velocity decreases. From the third configuration, the lift-off height highly depends on the velocity of annular jet flow but weakly depends on the central hydrogen jet flow. Generally, for all the mixing configurations, the lift-off height increases linearly with jet exit velocity.