Swirl Injector for Premixed Combustion of Hydrogen–Methane Mixtures

In the field of combustion, a special attention was given lately especially to the search for new, greener and more efficient fuels. Among them, hydrogen is intensely studied worldwide as a possible alternative fuel since new ways for producing and transporting it developed lately. Different studies are trying to confirm the possibility of the hydrogen transport using the existing natural gas distribution network, by mixing the two gases. Because the properties of the new mixture influence the combustion parameters, using the existing equipment would face new problems, like the risk of flashback, the effects of higher temperatures, and the modification of the flame front. Hence, new solutions are needed. In this context, this paper presents a newly developed and patented type of injector, designated for the combustion of the premixed hydrogen–methane fuel in various proportions. Based on the characteristics and dimensions of an existing combustion chamber of a gas turbine, different types of injectors were numerically simulated and compared. After the analysis of the results, the preliminary conclusions lead to a first swirl injector made from titanium alloy. The new type of swirled injector was tested on a cheap, simplified low pressure rig, designed to have similar dimensions to the initial combustion chamber, for preliminary validation of the main characteristics and of the stability of the new injector. The experiments indicated good lean blowout characteristics, and the promising results are encouraging for more future tests on a complex experimental setup, for optimizing the final solution.