Enabling detonation propulsion from wave to wall

Date: November 13, 2026; Time: 2:30 PM Location: PWEB 175

Abstract: Detonation propagation, whether in an accidental explosion in a coal mine or inside a detonation engine, relies on the coupling between the leading shock wave and the energy release behind it, as well as on their interactions with the surrounding confinement. Understanding these interactions, and the limits they impose, remains key to improved explosion mitigation strategies and to practical detonation-based propulsion. In this talk, I will illustrate the physics of detonation limits from two perspectives: how the wave responds to its confinement, and how the confinement responds to the wave. In the first part, we show that sustained propagation requires two conditions: a thermodynamic condition, in which energy release overcomes losses, and a geometric condition, in which the confinement accommodates the cellular structure of the detonation. Using a variable-geometry narrow-channel facility that isolates each condition, we find that the two limits are distinct, that which one governs depends on the mixture and the channel geometry, and that both ultimately arise from local decoupling of the shock and the reaction zone. In the second part, we turn to the wall. Using a miniaturized rotating detonation engine (RDE) purpose-built for materials testing, with precisely controlled exposure times, we follow how liners deform, oxidize, melt, and ignite over repeated runs, identify the mechanisms that lead to failure, and use the material response to infer the local environment created by the detonation. I will close by discussing open questions in detonation science and how understanding both the wave and the wall points toward the design of detonation-based propulsion and energy systems.

 Biographical Sketch: Xian Shi is an Assistant Professor of Mechanical and Aerospace Engineering at the University of California, Irvine. He received his Ph.D. in Mechanical Engineering from the University of California, Berkeley, and was a postdoctoral scholar at Stanford University. His research focuses on reacting flows: how chemistry and fluid motion couple in gases, in particle-laden flows, and at surfaces, and how that coupling can enable energy and propulsion technologies. Current topics include detonation dynamics and propulsion, plasma synthesis of carbon nanomaterials, and gas–surface interactions in extreme environments. He is a recipient of the AFOSR YIP award, an ARPA-E IGNIITE award, and a Hellman Fellowship.