Processing of Gun Propellants in Continuous Shear Roll Mills

Abstract

The processing of gun propellants can be carried out using the continuous shear roll milling process, which consists of two counterrotating and grooved rolls that are run at different speeds and temperatures and that exhibit different surface roughnesses. During the shear roll milling process, the water content of the propellant is decreased upon heat transfer with the rolls and upon the viscous energy dissipation generated, especially when the propellant is subjected to the shearing action at the nip regions between the two rolls. The propellant can also be granulated. In this process the propellant needs to stick to one roll and detach from the surface of the second roll. Here a mathematical model of the process is developed and is used to explain the experimental findings collected during the shear roll milling of a live gun propellant formulation.

Keywords:

• mill
• processing
• propellant
• shear roll

Acknowledgements

This work was supported by TACOM/ARDEC of Picattiny Arsenal, NJ, under contract DAAE30-01-C-1039. We are grateful for this support. We acknowledge with gratitude the contributions of Mr. James E. Kowalczyk and Mr. James B. Graybill of MPR Inc. of Hackensack, New Jersey, in the design and the manufacturing of the shear roll mill used in the experimental study. We also thank M. Malik, H. Tang, T. Kiryaman, and H. Filiz of Stevens; and C. Topolski, S. Rosenberg, D. Fair, A. Perich, W. Miller, N. Campesi, and E. Krajkowski of ARDEC at Picattiny Arsenal, Dr. Hays Zeigler of ATK Systems of Radford, Virginia; and Dr. A. Wellm of NitroChemie, Germany. We further thank the staff of NitroChemie for the diligent help they provided to our experimental program.