Non-ideal detonation properties of ammonium nitrate

In order to obtain a better understanding of the non-ideal detonation characteristics of ammonium nitrate, detonation velocity and pressure of low density prilled ammonium nitrate were measured in steel tubes with different diameters and wall thicknesses. It was found that the tube diameter has a much larger influence on the non-ideal behaviour of the detonation velocity and pressure than the confinement. The extrapolated detonation velocity and peak pressure to the infinite diameter were calculated as 3.83 km/s and 3.1 GPa respectively, which values coincide with the ideal detonation parameters for ammonium nitrate as predicted by the thermohydrodynamic TIGER code with the JCZ3 equation of state. Although the adiabatic exponent of the detonation gas products (y) remained constant when the confinement became heavier, it showed a remarkable change with the increase of the charge diameter. The extrapolated y value to the infinite diameter was obtained as 2.90 and it coincided with the y calculated with the TIGER code.