Critical tube diameter for detonation transmission and critical initiation energy of spherical detonation

Two experimental setups are used to study propagation and attenuation of blast waves. In the first one, the blast wave is generated by a spherical detonation, and in the second one, the blast wave is created by the diffraction of a planar detonation propagating in a tube. The similarity of these phenomena appears clearly by means of dimensionless space-time and pressure-space diagrams of shock wave propagation. Dimensionless variables are expressed as a function of the supplied energy. Two energy formulations are proposed: a piston model and a bulk energy model. The established diagrams cover a wide range of industrial applications. Under critical conditions, the energy released by a planar detonation is correlated to the ignition source energy supply and a relationship which links the critical radius of detonation to the critical tube diameter. Received 5 July 1997 / Accepted 13 July 1998