Vented Fixture Modeling
Abstract
Vented fixtures have been used extensively for erosion/erosivity investigation for many years. The fixtures can assist in quickly assessing materials/propellants and interactions as well as understanding mechanisms of erosion. In this report, two fixtures are modeled a 37-mm fixture at the U.S. Army Research Laboratory and a 2OO-mm bomb with a l-mm vent hole, located in Canada. Both fixtures erode a nozzle-type insert. The 37-mm fixture is designed to maintain a steady erosion quantity over repeated firings, with relatively small throat cross- sectional area change, which enables some insight into possible mechanisms. Each interior ballistic model required modifications to the interior ballistic code to enable a variable throat exit for the orifice. The Canadian fixture has a 1 -mm vent hole, which has a tendency to enlarge considerably during firing. The dominant erosion mechanism for the Canadian fixture is shown to be melt wipe, while for the 37-mm fixture, it is primarily thermochemical. A redesign of the Canadian fixture to permit a larger exit orifice with a rupture diaphragm would enable thermochemical differences in the propellants to reveal themselves better.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 2003
- Accession Number
- ADA413863
Entities
People
- Paul Conroy
Organizations
- United States Army Research Laboratory