Predictability of detonation wave dynamics in gases: experiment and model development

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Detonation waves are self-sustained supersonic combustion waves. These waves can be sustained in most energetic media including reactive gases. For safety applications, it is thus desirable to have the predictive capability for the eventual ignition of a detonation wave and for its propagation limits when different mitigation strategies are used. Likewise, propulsion applications of detonation waves (e.g., rotating detonation engines, pulse-detonation engine, oblique detonation engine) require accurate control of the wave initiation and stability. For all practical purposes, the detonation behavior needs to be predicted on scales on the order of meters (engine geometry, detonation arrestors, industrial facility configuration, etc...), whereas the detonation wave thickness phenomena occur at scales comparable to the molecular mean free path, i.e. less than a micron. The detonation phenomenon is thus an inherent multi-scale problem, with multi-scale physics. Adequate predictability of detonation wave dynamics is not currently possible at engineering scales. Achieving such predictability is the main thrust of my long-term research program on gaseous detonations. ******The research program applied for is a state-of-the-art multi-scale experimental and theoretical investigation of the phenomena controlling the reaction rates in detonation waves. Well-posed experiments at various scales of observations (the micro, meso and engineering scales) will permit to formulate and calibrate proposed closure models. At small scales, the influence of non-equilibrium effects and stochasticity stemming from molecular fluctuations will be studied in thermal ignition problems and compared with carefully designed experiments of critical ignition. At the meso-scale, our recently proposed Large Eddy Simulation strategy aimed at properly addressing both auto-ignition and turbulent mixing will be calibrated from the micro-scale experiments and simulations and tested against meso-scale dynamics of unstable detonation limits. Finally, the meso-scale experiments and simulations will permit the development and calibration of macro-scopic models at engineering scales for the appropriate global reaction rate in detonation waves. ******The outcome of the proposed research program is two-fold. Firstly, the development of a predictive capability of detonation related problems at the macro-scale engineering level through a bottom-up approach will find use in the prediction of such phenomena in the propulsion technology development and petro-chemical safety assessments. Secondly, and most importantly, it will provide training to students with the state-of-the-art solution methodologies in the field.