Testing of initiation of rotating detonation process in hydrogen - air mixtures

The paper presents results of some research work done in the project, which aims to apply of an innovative combustion chamber to the turbine engine. Expected benefits of using of a new chamber in which classical deflagration type combustion process would be replaced with a detonation combustion type, arise from greater efficiency of FickettJacobs cycle, which corresponds to rotating detonation combustion, in comparison to "classical" Brayton cycle, characteristic of deflagration combustion. The presented task concerned fundamental research carried out on test bench designed and built at the Institute of Aviation in Warsaw. To initiate the detonation combustion in the fuel-air mixtures the ignition device of appropriately high energy is necessary. The released energy should be directed to the area where the mixture has proper constitution - preferably close to stoichiometric one. Four different ignition manners were examined in the course of research: electrical ignition system adapted from turbine engine (semiconductor spark plug), powder charge ignition (handgun cartridges), detonation primer ignition using pentryt, and high voltage discharge (plasma jet). The appearance of detonation type combustion was identified on the basis of combustion gas pressure run, measured using piezoelectric sensors at a frequency of 1 MHz.