Ebook: Interior ballistics modeling: extensions to the one-dimensional XKTC code and analytical studies of pressure gradient for lumped parameter codes

Aberdeen Proving Ground, MD: Army research laboratory. 2001. – 184 p.We describe a number of extensions to the XNOVAKTC (XKTC) Code, a model of interior ballistic phenomena based on a numerical solution of the governing equations for one-dimensional, multi-phase flow. We also present some analytical formulations for the pressure gradient in a gun in a form suitable for incorporation into a lumped parameter interior ballistics model.
In XKTC, the flow resistance formula for stacked granular propellant is extended to account for the increase in drag due to tumbling of the grains as the bed expands. The code is also extended to permit the analysis of the consequences of propellant fracture, with fracture taken to be dependent on the local maximum intergranular stress. An explicit representation of the impact induced granular compaction wave as a surface of discontinuity is encoded to support the fracture analysis.
The analytical formulas for the pressure gradient include the effects of tube geometry and several aspects of the structure of the two-phase flow. The results are in a closed form with the breech and base pressure explicitly related to the spacemean pressure. Results are presented for both granular and stick propelling charges.