Effect of mechanical stresses on the combustion velocity of mixed solid fuels

Abstract

It is well-known that the velocity of stationary combustion of mixed solid rocket fuels depends on the stressed state in them. A theoretical description of the effect of mechanical stresses on the combustion velocity of solid rocket fuels should be based on the one hand on the theory of combustion of condensed fuels, taking into account their complex multizone structure and, on the other hand, on the description of the changes of properties of the near-surface layer as a result of the stressed state of the fuel. In particular, it is necessary to describe the origination of gas permeability anisotropy of the near-surface layer. In accordance with the concepts developed in this paper, the combustion velocity of a solid fuel, subjected to tension, is different depending on the direction of combustion. Combustion from a surface parallel to the stretching force takes place with a higher velocity than in an orthogonal direction. Repeated deformations of the sample can lead to the buildup of defects and cracks, and can cause an even greater increase of the combustion velocity in the stressed state.