Effect of Bluff Body on Combustion Characteristics of Secondary Combustion Chamber of Solid Rocket Scramjet with Boron Contained

Solid scramjet can be divided into solid rocket scramjet and solid fuel scramjet. Compared with solid fuel scramjet, the solid rocket scramjet has the advantages of good flame stability and more alternative mixing methods. Boron is widely used in solid fuels as a solid additive with high calorific value. However, the hard to volatilize oxide layer prolongs the ignition time of boron particles. In addition, the short residence time of particles in the supersonic afterburning chamber makes it difficult for the energy of primary gas with boron contained to play a full role, which makes the performance of solid rocket scramjet insufficient.

In order to improve the combustion efficiency of primary gas with boron particles contained in the combustion chamber of solid rocket scramjet for enhancing the engine performance, the effects of different blunt body types and blunt cone angle on the combustion characteristics are calculated and analyzed by numerical method. The results show that the combustion efficiency of boron particles in the second chamber with basic blunt body is the highest, but the specific impulse is the lowest among the three types of different bluff bodies. For the influence of bluff body cone angle, the combustion efficiency of bluff body combustor with 30 degree angle is the highest among 25, 30 and 35 degree angles. But when the cone angle is 25°, the specific impulse is the highest.