Detonation propagation in narrow gaps with various configurations

In general all detonation waves have cellular structure formed by the trajectory of the triple points.This paper aims to investigate experimentally the propagation of detonation in narrow gaps for hydrogen-oxygen-argon mixtures in terms of various gap heights and gap widths.The gap of total length 1500 mm was constructed by three pair of stainless plates,each of them was 500 mm in length,which were inserted in a detonation tube.The gap heights were varied from 1.2 mm to 3.0 mm while the gap widths were varied from 10 mm to 40 mm.Various argon dilution rates were tested in the present experiments to change the size of cellular structure.Attempts have been made by means of reaction front velocity,shock front velocity,and smoked foil to record variations of cel- lular structure inside the gaps.A combination probe composed of a pressure and an ion probe detected the arrival of the shock and the reaction front individually at one measurement point.Experimental results show that the number of the triple points contained in detonation front decreases with decrease in the gap heights and gap widths,which lead to larger cellular structures.For mixtures with low detonability,cell size is affected by a cer- tain gap width although conversely cell size is almost independent of gap width.From the present result it was found that detonation propagation inside the gaps is strongly governed by the gap height and effects of gap width is dependent on detonability of mixtures.