Measurement and analysis of the cell size caused by fuel-air detonation in a vertical shock tube

The cell sizes caused by fuel-air cloud detonation were investigated by smoked foil in a vertical shock tube. It indicates that the relationship of the cell sizes and equivalence ratios shows a U-curve, The minimal cell size is obtained when equivalence ratio is slightly larger than 1. This result is similar to that in gaseous detonation. A more complex celluar structure takes place with the enhancement of ignition energy. The cell size of hydrocarbon-air cloud increases with the number of carbon atoms, and the ratio of its length to width is less than that of the gaseous fuel. Experimental results are helpful to understand the detonation nature of hydrocarbon fuel-air mixtures.