Study on mixing and combustion characteristics of solid rocket ramjet with a large angle of attack

Solid rocket ramjet faces the problems of large angle maneuvering and stage transformation in the actual operation. In order to study the effect of the change of angle of attack and excess air coefficient on the performance of boron-containing solid rocket ramjet, the fluid field with different conditions were calculated. The applicability of the numerical model was verified by ground direct-connected experiments. The results showed that as the angle of attack increases, the mixing in the head reflux area and the initial air-gas contact area are enhanced. The combustion ratio of combustible components in the front section is greatly increased, which helps to improve the combustion efficiency of the motor. When the excess air coefficient increases from less than 1 to much greater than 1, the mixing combustion in the head region is also strengthened. However, the radial impact of excess air causes the gas to deflect to the upper side of chamber, and then most of the particles move close to the wall, resulting in a lower level of combustion. The general trend is as follows, under the same mixing-dominated pattern, the average mixing at the outlet decreases with increasing angle of attack, and the combustion efficiency is reversed. Under different mixing-dominated patterns, higher combustion efficiency can be obtained at lower mixing when the head region dominates.