Swirl Injector for Premixed Combustion of Hydrogen–Methane Mixtures

Among the present domains of interest in scientific research, the field of combustion gained more and more attention, especially the search for new greener and more efficient fuels. One idea that is intensely studied worldwide is the possibility of using hydrogen, since new ways for producing and transporting it developed lately. Different studies are trying to confirm the possibility of 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 new developed and patented type of injector designated to the combustion of premixed hydrogen-methane fuel in various proportions. Based on the characteristics and dimensions of an existing combustion chamber of Garrett GTP30-67 gas turbine, different types of swirled injectors were numerically simulated and compared. After the analysis of the simulation results, plastic models were produced using 3d printing technology. The preliminary conclusions lead to a final pilot injector, made from titanium alloy. The new type of swirled injector was tested on a low pressure rig designed to have similar dimensions to the combustion chamber of the initial gas turbine. For the experiment only natural gas was used as fuel. Finally, the experiments showed a stable and efficient working flame can be obtained with the new type of injector. Moreover, the results confirmed the possibility of developing and improving the new found type of swirled injector for other types of combustion applications.