Performance of unconfined detonable fuel aerosols of different height to diameter ratios

Abstract

Unconfined fuel aerosols known as fuel air explosives (FAE) are detonable in nature over a wide range of fuel concentrations in air. The fuel aerosols are formed by dispersing the fuel in air by explosive means and detonated using a suitable initiator charge leading to the generation of a high impulse blast. For weapon applications, the designers aim for higher lethal area for damaging soft targets. Theoretical estimations have shown that aerosols of lower height to diameter ratio (H/D) produce higher blast pressures at longer distances, thereby enhancing lethal area. However, there is no experimental data available in the open literature to validate the theoretical findings. In this study two approaches were followed to generate detonable aerosols of different H/D, viz.; use of different burster charge loadings for a given fuel container known as canister and fuel quantity and use of different size canisters for the same fuel quantity and burster charge loading. The aerosols formed by a given size of canister and 4.2 kg propylene oxide with different burster charge loadings having similar H/D values and blast performance. In the second approach, a canister with lower H/D containing 18.5 kg propylene oxide generated aerosols of lower H/D and higher blast performance at longer distances as compared to that of a canister with higher H/D with the same fuel quantity. The better canister fragmentation and fuel dispersion observed for the canister of lower H/D has been attributed to the better utilization of burster charge energy as evident from theoretical estimation of the time period for completion of the burster charge detonation and shock wave travel to canister wall. The experimentally observed initial velocity of fuel dispersion was found to be in well agreement with the theoretically estimated values. The results indicate tailorability of blast performance for a given quantity of fuel by choosing the canister H/D. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.