PETN Experimental Detonation Pressures

The LMU Munich research group has also been looking at tetrazole-free nitrogen-rich compounds that contain oxidizing groups such as nitramine functionalities. In this context, the preparation and structural characterization of dinitrobiuret (DNB) (Fig. 31) was carried out [109,110]. The high chemical and thermal stability of DNB and the determined critical diameter of 6 mm for DNB (Figs. 32, 33) in the Koenen test (steel shell test) is comparable to the values reported for HMX (8 mm), RDX (8 mm), or PETN (6 mm) and prompted us to obtain the thermodynamic data and detonation pressures and velocities for DNB in a combined experimental and theoretical study. 

Some explosives do not exhibit appreciable amounts of build-up. PETN has minimal build-up behavior as a function of distance of run. The performance of PBX-9502 (95/5 wt% TATB/Kel F at 1.894 g/cc) is reported in reference 46. The initial free surface of Dural plates driven by 1.25, 2.5 and 5.0 cm thick slabs of PBX-9502 appeared to scale as a function of Dural plate thickness to PBX-9502 thickness within the large uncertainities associated with the experimental data. Recently the Russians have performed more accurate TATB experiments and found a 20% change in the effective C-J pressure for charge lengths of 3 to 18 cm with only a 2% change in detonation velocity. This study is described in section 2.9. 

As shown in Figure 2.72, the condensed carbon contribution to the PETN heat of explosion is small, as there is almost no solid carbon in its detonation products. For TATB the apparent heat of explosion depends primarily on the size of the condensed carbon. The average size of the carbon clusters, and hence the heat of explosion, depends on the time of existence of high pressures and temperatures during which the carbon cluster growth is possible. This is the fundamental reason for the effective heat of explosion dependence on the experimental conditions and in particular the steepness of the Taylor wave which is determined by the distance of run in one-dimensional flow. 

The underwater explosion parameters were measured in the range of an initial pressure between 0.1 and 0.9 MPa and compared with the known parameters of TNT and PETN explosions [45, 46]. The higher initial pressures (up to 10 MPa) were applied to underwater explosions of 2H2 + O2 mixture contained in spherical glass ampoules [48]. Below, experimental results obtained in underwater detonation blasts of gas-filled spherical thin-waU rubber cavities are analyzed. 

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