Adaptive Mesh Refinement-Based Numerical Simulation of Detonation Initiation in Supersonic Combustible Mixtures Using a Hot Jet

摘要

An open-source program implementing a block-structured adaptive mesh refinement method was adopted for the fine structure numerical simulation of detonation initiation in supersonic combustible mixtures. Simulations were conducted on a nested parallel computing system. The initiation process was specified as three stages, and their respective flow field characteristics were analyzed. Results indicate that a hot jet under specific conditions can have a similar effect as a pneumatic oblique bevel for inducing periodical shock-induced detonative combustion by a bow shock. The interaction of bow shock-induced combustion with the local detonation wave, produced by the reflection shock on the upper wall, can create a structure with two triple-wave points. The hot jet not only plays a role in the detonation initiation but also acts as a stabilizing control mechanism for detonation propagation. In the simulations in this study, the detonation wave propagates in an overdriven state initially and achieves self-sustaining motion after the shutdown of the hot jet. Subsequently, the final pisiform structure of typical stable Chapman-Jouguet detonation cells is formed.