Regularity of detonation cellular structures in hydrocarbon mixtures of moderate effective activation energies

Abstract

The influence of gasdynamic and chemical kinetic properties on cellular detonation structure is experimentally investigated through CH-O, CH-O, and H-O detonations with different diluents and O addition. Eight hydrocarbon mixtures are designed to independently vary the detonation gas dynamic effect, characterized by the post-shock mixture specific heat ratio , and the chemistry effect, characterized by the effective activation energy . A statistical representation of the cellular regularity is proposed to quantify the degree of geometric irregularity. For the range of considered, under a constant , cell regularity is found to have no clear dependence on . However, under a constant , cell irregularity is found to increase significantly with increasing , generalizing the findings of previous studies on H-O cell regularity. A scaling argument based on local kinetic sensitivity is proposed to describe the effect of on cell regularity. The scaling result is found to be in good agreement with experimental data.