Hydrocarbon fuel-air mixture

The d = 13 X law led the author to develop a simple model whereby the critical energy for initiation can be predicted when the cell size and the equilibrium Chapman-Jouguet detonation states are known. This simple so-called surface energy model of Lee (34) gave predictions for the critical initiation charge weight for various hydrocarbon fuel-air mixtures in close accord with the experimental data obtained by Elsworth (39). 

Chapman-Jouguet detonation velocity (CJDV) Ideal detonation velocity that satisfies Chapman-Jouguet condition at the end of the reaction zone a gas moves at the velocity equal to the difference between the detonation velocity and the sound speed in the combustion products. CJDV in a stationary moving detonation wave is calculated from the thermodynamic equilibrium condition of the reaction products and the mass, impulse, and energy conservation laws. CJDV for typical hydrocarbon fuel + air mixtures lies in the range from 1,400 to 1,900 m/s. 

---