Simulations of Special Interior Ballistic Phenomena with and without Heat Transfer to Gun Tube Wall

摘要

The computer code DELTA uses a linearized Alternating Direction Implicit (ADI) scheme to provide a numerical approximation of the solution of the averaged two-phased (gas-solid) two-dimensional (axisymmetric) equations governing viscous interior ballistic flows within conventional guns. To further the understanding of phenomena affecting gun tube life as well as gun performance, a heat of transfer model, which simulates the interactions of fluid dynamics and thermal profile in the gun tube wall, has been incorporated in the DELTA code. The same linearized ADI method was utilized to obtain the numerical solution of the two-dimensional nonlinear heat conduction equations in the gun tube. Our model of the heat transfer process couples completely and simultaneously all three controlling events without any approximations to the governing equations; that is, the axisymmetric viscous flow within the entire gun tube which naturally gives a precise definition of the gas thermal boundary layer, the time-dimensional temperature calculation within the gun tube wall. The nonlinear heat flux boundary conditions at the inner and outer tube surfaces are linearized to be compatible with the soluton scheme. Results computed with DELTA are presented for two different types of idealized one-phase interior ballistics flows. The first is a pure expansion flow, and the other includes mass and heat sources. For each of the flows we present the effects of gas turbulence and the effects of heat conduction to the wall. Our results indicate that both effects are significant. (Author)