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Lumped Parameter Analysis of Bridge Wire in an Electro Explosive Device of a Power Cartridge for Water-Jet Application: A Case Study

Parate Bhupesh Ambadas, Chandel Sunil, Shekhar Himanshu

Central European Journal of Energetic Materials

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2020

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Vol. 17, no. 3

408--427

EN

In an armament system an electro-explosive device (EED) essentially converts electrical energy into heat which further initiates the explosive train with its accompanying temperature rise. The first function of an EED in a power cartridge is to provide adequate electrical current to cause ignition of the highly sensitive explosive i.e. lead styphnate. The electrical current accomplishes ignition by heating the bulb of lead styphnate which produces enough heat to cause the booster to ignite. The booster which is in the immediate vicinity augments the ignition of the propellant further. The igniter must be held firmly in place with the booster in the tube. Understanding of the initiation of explosives using a bridge wire in EEDs is important for engineers, designers and scientists to develop new theories. In this research article, theoretical and experimental work has been reported pertaining to bridge wire devices in power cartridges for water-jet applications. The objective of the present research work is to use lumped parameter analysis of a bridge wire in an electro explosive device of a power cartridge for water-jet application. A lumped parameter theory is proposed for the analysis of EEDs. A time constant of 3.35 s has been determined using the lumped parameters. The Biot number is less than 0.1 indicating that transient phenomenon is applied.

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Design Analysis of Closed Vessel for Power Cartridge Testing

Parate Bhupesh Ambadas, Chandel Sunil, Shekhar Himanshu

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2019

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Vol. 10, Nr 1 (35)

25--48

EN

This paper discusses the design analysis of closed vessel (CV) for power cartridge application in water-jet disruptor. In this article, various design theories are presented in which the vessel is subjected to internal pressure. CV is a kind of pressure vessel utilized to evaluate the performance of power cartridge used for water-jet application. It is a test vessel which generates pressure - time profile by burning the propellant. Energy derived from burning of the propellant of power cartridge aids in neutralizing Improvised Devices (IED's). This energy creates high water-jet plume in the disruptor. In order to evaluate various performance parameters of the cartridge, CV design plays a vital role in the research and development activities, including, development, life trials, production, lot proof trials and life extension / life revision trials. CV is one of the methodologies / techniques from which energy generated is measured in terms of the maximum pressure (Pmax) and the time to maximum pressure (TPmax). This paper also discusses about various design aspects using the finite element method (FEM) and their comparative results with different design theories. In the light of these theoretical, numerical, and experimental works, it was recommended that octahedral stress theory or van Mises theory should be used for vessel design. This satisfies the designer requirements. FEM analysis tool helps in reducing time & development cost.

3

A Novel Method for Dynamic Pressure and Velocity Measurement Related to a Power Cartridge Using a Velocity Test Rig for Water-Jet Disruptor Applications

Parate Bhupesh Ambadas, Salkar Yogesh Balkrishna, Chandel Sunil, Shekhar Himanshu

Central European Journal of Energetic Materials

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2019

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Vol. 16, no. 3

319--342

EN

Power cartridges are gas generators utilised to drive a liquid projectile for disruption of suspect improvised explosive devices (IED’s). The purpose of a water-jet disruptor is to destroy the suspected IED. A novel method was devised for pressure measurement at the exit of the cartridge for launching liquid projectile. An experimental test set-up was designed and fabricated for measurement of projectile velocity and the propellant gas pressure in a velocity test rig (VTR). In these experiments, double base propellants having different physical and chemical properties were utilised to drive the solid projectile. This projectile was made of nylon material. This projectile velocity measurement is an important parameter in the armament field. An experimental study is the unique design feature. It is responsible for the measurement of pressure at the exit of the cartridge and the projectile velocity at the muzzle end of the barrel. The projectile velocity was measured using high speed photography. The pressure was measured using a pressure sensor. The maximum projectile velocities for spherical ball powder and NGB 051 propellants have been experimentally measured as 384.23 m/s and 418.32 m/s, respectively. Experimentally the maximum pressures for spherical ball powder and NGB 051 propellants have been evaluated as 50.12 MPa and 63 MPa respectively from data gathered by the acquisition system. The standard deviation between the experimental and theoretical values for the projectile velocity varied from 12.57 to 13.88 for spherical ball powder whereas it was 5.33 to 7.09 for NGB 051 propellant. The percentage error between the experimental and the theoretical values of the projectile velocity was less than 10 for both propellants.