Detonations of starch suspensions in gaseous O2/N2 and stoichiometric H2/O2 mixtures

A model is developed for investigating detonation in various situations when starch particles are added. The model shows that in the presence of starch particles, the detonation velocity can exceed significantly the equlibrium thermodynamic detonation velocity, and only slightly depends on particle concentration (for relatively coarse particles). The model predicts that the thermodynamic detonation velocity can be achieved in hybrid mixtures with fine starch particles only a few micrometers in size. It is also shown that under the experimental conmditions of Peraldi and Veyssiere (1986), the dominant detonation propagation regime is the so-called pseudo-gas detonation, and that the propagation of a double-front detonation (DFD) is unlikely under these conditions. It is inferred that the second discontinuity observed in the pressure profiles reported in Peraldi and Veyssiere would have a different nature from the DFD observed by Veyssiere (1986) in hybrid mixtures with aluminum. The present results show the value of approximate modeling comprising 1D gasdynamics and global kinetic schemes in investigating complex problems of detonation initiation and propagation in two-phase reactive mixtures. (AIAA)