Combustion enhancement effect of dual combustor ramjet engines on boron-based propellants

To investigate the combustion enhancement effect of the Dual Combustor Ramjet engine（DCR）configura⁃ tion on boron-based propellants and its contribution to engine performance，the scramjet engine（SCR）was selected for comparison. The results indicate that，compared to SCR，the DCR effectively promotes the combustion of boron-based propellants under the conditions of Ma=5 at 28 km height（Case 1）and Ma=6 at 30 km height（Case 2），ben⁃ efiting from the high-temperature and high-pressure environment of the subsonic combustor，while maintaining rela⁃ tively low total pressure loss and better engine performance. In Case 1，the combustion efficiency of DCR is higher than that of SCR by 26. 6%，27. 2%，and 23. 8% for engine lengths of 1. 5 m，2 m，and 2. 5 m，respectively，with specific impulses of 1 964 m/s，1 970 m/s，and 1 406 m/s. In Case 2，DCR shows combustion efficiencies higher than SCR by 27. 9%，22. 3 %，and 22. 9 %，with specific impulses of 1 615 m/s，1 393 m/s，and 960 m/s，respec⁃ tively. The shorter the engine length，the more pronounced the performance advantage of DCR over SCR，indicating that DCR is preferable in space-constrained application scenarios.