Ignition Delay Times of Hydrogen-air Mixtures at Ultra-high Pressures Inside a Shock Tube

Hydrogen–synthetic air mixtures under engine-relevant conditions remain insufficiently characterized in literature, particularly at elevated pressures required for rocket engines and heavy-duty hydrogen internal combustion engines. In this study, experimental pressure traces were measured during the oxidization of hydrogen using the high-pressure shock tube (HPST) at the University of Central Florida. The experiments were conducted at reflected-shock pressures of 100 bar and temperatures ranging from 1017 to 1074 K. These conditions allow for the investigation of ignition behavior relevant to practical engine operation. The resulting pressure traces and ignition delay data provide needed insight into hydrogen autoignition characteristics at conditions that remain largely unexplored in the existing literature. A notable temperature sensitivity has been observed for lower dilution hydrogen mixtures at 100 bar.