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

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.