Adjoint-based optimisation of detonation initiation by a focusing shock wave

Abstract An optimisation study of a shock-wave-focusing geometry is presented in this work. The configuration serves as reliable and deterministic detonation initiator pulsed engine. combustion chamber consists circular pipe with one convergent–divergent axisymmetric nozzle, acting focusing device for an incoming shock wave. Geometrical changes are proposed to reduce the minimum wave strength necessary successful initiation. For that purpose, adjoint approach applied. sensitivity initiation flow variations delivered by method used reshape obstacle’s form. thermodynamics described higher-order temperature-dependent polynomial, avoiding large errors constant adiabatic exponent assumption. chemical reaction stoichiometric premixed hydrogen-air modelled means one-step kinetics variable pre-exponential factor. This factor adapted reproduce induction time complex model. results 5% decrease incident threshold