Comparative analysis for combustion ch4 and h2 for coaxial jet burners (diffuse combustion)

The use of hydrogen as a fuel requires as much research as possible on the construction and functional parameters for the development of appropriate burners. The researches undertaken are addressed to diffuse flame burners with concentric jets of fuel and air. These burners cannot lead to flame return, the combustion being much safer, than for the case of burners with fuel-air mixture. The researches were carried out by numerical modeling through the ANSYS-FLUENT V.14.0 software. An important stage of the research, carried out theoretically, included the establishment of the hydrogen velocity at the exit of the burner section. Compared to this size, the question of the level of air velocity in the accompanying jet was further raised. It simulated operation with both a low level of air velocity and a high level up to the value of the fuel speed. The processing of the obtained data demonstrated the superiority of the flames with high air velocities, but also the great concordance between the flame obtained at the combustion of hydrogen with that of methane. The numerical modeling aimed at determining the conditions of hydrogen combustion for a hydrogen-air coaxial admission for the realization of methane-like flames. This also responds to the behavior of the hydrogen flame in the combustion chambers of the gas turbines, which are intended to modify the burner and not the room itself. The fact that the length of the hydrogen flame was about 10% below that of the methane flame also gives a positive response to this technical application. If in gas turbines the fuel compressor can provide hydrogen speed at the outlet of the burner, for other industrial applications there remains an open problem of ensuring hydrogen pressure.