Estimation of Recoil Energy of Water-Jet Disruptor

Water is used as a liquid projectile in a disruptor for destruction of various dangerous objects such as improvised explosive devices (IED’s). This weapon is light weight and experiences certain recoil during a firing action. As there is motion between a projectile and a barrel, a recoil is experienced by the weapon. The recoil of weapon works on a conservation of momentum equation which is based on Newton’s second law of motion. A water-jet is created due to intense gas generation by a propellant burning inside the cartridge. The gas energy obtained by burning the propellant is responsible for pushing the projectile in a forward direction through the barrel. Due to gas generation by propellant burning, there is forward motion of the projectile. An attempt is made to determine the theoretical recoil velocity, its energy for the projectile in a water-jet application. The minimum and maximum recoil velocities of a water-jet varies from 2.311 m/s to 2.611 m/s. The order of magnitude for the recoil velocities is small and can be compared with a recoil of small calibre weapons that these weapons experienced during a firing mode. Based on recoil velocities, minimum and maximum kinetic energies of recoil parts are determined as 3.73 kJ and 4.77 kJ, respectively. The maximum gas force experienced by the projectile is worked out as 13.46 kN. The minimum and maximum energies to overcome the resistance force are determined as 14.657 J and 18.711 J, respectively. A small exercise for spring design is also covered.

Experimental and Theoretical Determination of Water-Jet Velocity for Disruptor Application Using High Speed Videography

Experimental and theoretical determination of water-jet velocity using high speed videography for disruptor application is reported in this paper. Water-jet disruptor extensively uses the water as a liquid projectile. It helps to destroy improvised explosive devices (IEDs) or explosive devices (EDs) by breaking detonating cord in the system, making it non-operational. The use of such system against suspected objects is a fashion that continues to be met tremendous achievement. Such a device is also known as explosive ordnance disposal (EOD) disruptor. It is used by bomb technicians or squad to make disable and/or neutralize at a safe distance. The primary purpose of an EOD disruptor is to remotely open or provide destruction to suspected objects. To “remotely open” is to open the suspect objects, exposing their contents. “Provide destruction” means penetrating, cutting, or removing the components of the fusing system in order to make them disable. A secondary purpose of a disruptor is to create a means of access (for example, through a window or door of vehicle or into a trunk). Double and single base propellants are used in the experimental trials for assessing water-jet velocities. An attempt has been made to validate the water-jet velocity using experimentally high speed videography for the first time and making its theoretical analysis by conducting the various trials at a laboratory with different propellants. The stand-off distance between disruptor and target is 0.5 m. This kind of research work is not reported in open access till the date. This is the newness of this research work. The experimental water-jet velocity for single base propellant varies from 349.63 to 503.56 m/s and for double base propellant it varies from 515.07 to 890 m/s. The theoretical water-jet velocity for single base and double base propellant works out to be as 616.44 m/s and 692.62 m/s respectively. From this research study, it is concluded that there is good agreement between theoretical and experimental results.