Subsonic mode combustion in cylindrical secondary combustors of Air Breathing Rockets (ABR) was investigated. Experiments determined the influence of oxidizer-fuel ratio of the primary rocket, mass flow ratio of secondary air to the primary rocket propellants, and length of secondary combustors on the performance of ABR. Gaseous hydrogen and gaseous oxygen were used as the primary rocket propellants and compressed air at room temperature was used as secondary air. Experimental results were compared with ideal conditions calculated on the assumption of complete mixing and burning. A one-dimensional analysis made it possible to calculate axial distribution of flow properties. From the calculated stagnation temperature distribution, we determined "effective flame length" lf. The performance of the secondary combustors correlated well to the non-dimensional combustor length L lf. Cross sectional distribution of flow properties were obtained from gas sample and Pitot pressure data. Combustion efficiency was also obtained by integrating heat release flux over an exit cross sectional plane. Using a model assuming incomplete mixing and burning, combustion efficiency and other properties were related to the ratio of the exit pressure to the theoretical projection based on the complete burning model. These results agreed well with the experiments.
ASJC Scopus subject areas
- Aerospace Engineering