Hot surface ignition dynamics in premixed hydrogen–air near the lean flammability limit
The dynamics of ignition of premixed hydrogen–air from a hot glow plug were investigated in a combined experimental and numerical study. Surface temperatures during heating and at ignition were obtained from 2-color pyrometry, gas temperatures were measured by high-speed Mach–Zehnder interferometry, and far-field effects were captured by high-speed schlieren imaging. Numerical simulations considered detailed chemical kinetics and differential diffusion effects. In addition to the known cyclic (puffing) combustion phenomenon, singular ignition events (single puff) were observed near the lean flammability limit. Detailed analysis of the results of our numerical simulations reveal the existence of multiple combustion transients within the thermal boundary layer following the initial ignition event and, at late times, sustained chemical reaction within a thermal plume above the glow plug. The results have significant implications for ignition from hot surfaces within near-flammability limit mixtures, at the edge of plumes resulting from accidental release of hydrogen, or within the containments of nuclear power plants during severe accidents.
© 2019 The Combustion Institute. Published by Elsevier. Received 5 February 2019, Revised 11 March 2019, Accepted 1 September 2019, Available online 28 September 2019. The present work was carried out in the Explosion Dynamics Laboratory of the California Institute of Technology and was supported by The Boeing Company through a Strategic Research and Development Relationship Agreement CT-BA-GTA-1. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by the National Science Foundation grant number ACI-1548562.
Accepted Version - CNF_BM-GS_2019.pdf
Supplemental Material - 1-s2.0-S001021801930416X-mmc1.pdf