| The problem of direct initiation of detonations has been investigated numerically by using a more realistic chemical kinetics scheme. The chemical kinetics model is based on a three-step chain-branching reaction consists sequentially of a chain-initiation and a chain-branching step, followed by a temperature independent chain-termination. The steady ZND structure using the 3-step chemical kinetics model is compared with that based on the standard single-step Arrhenius rate model. An unsteady computation has also been performed to determine whether the solution from steady-state analysis can be approached asymptotically from a transient development.; The three regimes of direct initiation have been numerically simulated for planar, cylindrical and spherical geometries using the present 3-step chemical kinetics model. The use of a more realistic reaction scheme allows a unique value for the critical initiation energy to be defined.; Some general theories for direct initiation have been verified from the results of the present numerical simulation using a more detailed chemical kinetics model, where a definitive value of the critical energy was obtained. (Abstract shortened by UMI.)... |
