Gun barrel erosion: comparison of conventional and LOVA gun propellants

The research department Energetic Materials within TNO Defence, Security and Safety is involved in the development and (safety and insensitive munitions) testing of conventional (nitro cellulose based) and thermoplastic elastomer (TPE) based gun propellants. Recently our testing capabilities have been extended with vented vessel tests in order to investigate whether or not newly developed (low vulnerability (LOVA)) gun propellants or propellant formulations perform better in erosion tests. At the moment we have two vented vessel tests available, making it possible to determine the extent of erosion from a relatively low loading density to one comparable to a large caliber gun (maximum allowable pressures from 20 to 400 MPa). Test pieces of various materials have been used and a number of LOVA and conventional gun propellants have been tested. From the results of these experiments the wear and wear rate have been determined. The erosion dependency on propellant properties like impetus, flame temperature, and combustion gas composition has been determined. Furthermore, an internal ballistics code has been adapted to model the pressure and temperature development in a vented vessel. The results are compared with the experimental results. This model will be described in short and the results presented