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Mechanical and Ballistic Properties of Spherical Single Base Gun Propellant

Boulkadid K. M., Lefebvre M. H., Jeunieau L., Dejeaifve A.

Central European Journal of Energetic Materials

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2017

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Vol. 14, no. 1

90--104

EN

The effect of the initial temperature on the mechanical properties of spherical single base gun propellant was investigated by means of a compression test, which consisted of compression of a propellant bed conditioned at various initial temperatures. Following this mechanical treatment, the pressed grains (after thermal conditioning at ambient temperature) were tested in a closed vessel. The results from the combination of compression and closed vessel tests supported the assumption that there are two phenomena occurring inside the cartridge at low temperatures which compensate each other; the first is a decrease in the burning rate as the initial temperature is decreased, and the second is grain fracturing occurring on ignition. Additionally, a specific parameter, the specific surface area, turns out to be an appropriate parameter for quantifying the mechanical damage to the propellant grain resulting from the compression test. Tests on the aged propellant have also been conducted.

2

Local Temperature Sensitivity Coefficients of a Deterred Spherical Single Base Gun Propellant

Boulkadid K., Lefebvre M. H., Jeunieau L., Dejeaifve A.

Central European Journal of Energetic Materials

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2017

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Vol. 14, no. 4

952--965

EN

In our previous investigation, we measured the global temperature sensitivity coefficient of a deterred spherical single base gun propellant following an experimental procedure that did not allows us to determine the local temperature sensitivity coefficients of the deterred and undeterred parts of the investigated propellant. In this paper, we propose an experimental methodology to measure the local temperature sensitivity coefficients of both parts of the spherical deterred gun propellant. This methodology can be summarized as follows: Firstly, we separated the ranges of pressure where the combustion of the deterred and the undeterred parts of the spherical propellant occurs by means of infrared (IR) microscopy measurements. Then the burning rate of the propellant as a function of pressure was calculated according to STANAG 4115 at different initial temperatures. Finally, we determined the local temperature sensitivity coefficients of each part of the spherical propellant.

3

Temperature Sensitivity of Propellant Combustion and Temperature Coefficients of Gun Performance

Boulkadid M. K., Lefebvre M. H., Jeunieau L., Dejeaifve A.

Central European Journal of Energetic Materials

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2016

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Vol. 13, no. 4

1005--1022

EN

One of the objectives of gun propellant research is to develop green formulations of gunpowder that should be less temperature sensitive than the current gun propellant. The temperature sensitivity of these new green formulations of the propellant should be measured to identify the less temperature sensitive green formulations. However, there are deficiencies in the methodologies for the measurement of the temperature sensitivity of gun propellants. Therefore, the aim of this investigation was to fill the gap by establishing a method for the measurement of the temperature sensitivity of deterred gun propellants by closed vessel tests. The temperature sensitivity of the burning rate of ball propellants and the temperature coefficients of gun performance were determined using closed vessel tests and ballistic firing, respectively. Specific definitions of temperature sensitivity and temperature coefficients were evaluated. The relation between these parameters has never been explicitly investigated previously. Assessing the temperature sensitivity of propellants by closed vessel tests is of added value to the range of ballistic tests if the results of these tests can be well correlated to the results of ballistic firings. Therefore, a comparison between both parameters was made. A correspondence has been observed between the temperature sensitivity of the propellant burning rate, as obtained from closed vessel tests, and the temperature coefficients as obtained from ballistic firings.