Inorganic Nanoparticles for Gun Propellants
- PDF / 274,156 Bytes
- 12 Pages / 612 x 792 pts (letter) Page_size
- 58 Downloads / 248 Views
0896-H03-07.1
Inorganic Nanoparticles for Gun Propellants B. Baschung French-German Research Institute of Saint-Louis 5, rue du Général Cassagnou, BP 70034, 68301 Saint Louis, FRANCE
ABSTRACT The possibility of increasing the burning rate of solid rocket propellants by adding nanoparticles of aluminum into the propellant formulation has already been well-known for many years. This paper deals with micron- and nanoparticles embedded in gun propellants. The objective is to increase the gun performance. The burning behavior of solid propellants based on ultra-fine aluminum powder was investigated in a high pressure range which is reached in a gun tube. The burning rate of such a propellant is much higher (nearly two orders of magnitude) than for the similar propellant with the micron-sized aluminum. This paper presents a review of burning experiments with propellants based on the nano- and micron-sized particles of aluminum. The burning behavior of NENA solid propellants based on nanoscale aluminum was studied as a function of the portion of aluminum in the mixture. The burning of these propellants follows Vieille's burning law. The burning rate increases by augmenting the aluminum portion in the propellant. Theoretical models are reviewed in order to understand these experimental burning results. An advanced propellant coated with appropriate nanoparticles is presented in the conclusion. With this propellant and a special ignition by microwaves it should be possible to ignite solid propellants by using high loading densities (> 1.2 g/cm3).
INTRODUCTION The possibility of increasing the burning rate of solid rocket propellants by adding nanoparticles of aluminum into the propellant formulation has already been well-known for many years [1-4]. This paper deals with micron- and nanoparticles embedded in gun propellants. The main objective is to increase the gun performance. As there are differences in the nomenclature of processes between rocket propulsion and interior ballistics, some helpful comments on interior ballistics are given in this introduction. The performance of a weapon is defined by the muzzle energy E0 of the projectile. It is proportional to the square number of the muzzle velocity v0 and to the mass mp of the projectile. This performance is seriously influenced by the ignition delay time t1, the dynamic combustion of the propellant, and the conditions of the burnt gases during the polytropic expansion phase. Fig. 1 shows a typical pressure history curve recorded during the acceleration of a projectile in a weapon barrel. The integral of p·dt between the limits t1 (ignition of the propellant) and t2 (exit of the projectile from the weapon muzzle) is proportional to the muzzle velocity of the projectile if the caliber of the weapon and the mass of the projectile are constant. It seems that an increase of performance is easily reached with high propellant loadings. But the maximum pressure is restricted to the weapon construction. Therefore, an increase of the performance is very complex and can be reac
Data Loading...
