Comparison study of RBCC powered suborbital reusable launch vehicle concepts

The performance of air-breathing launch vehicle is quite sensitive to utilized airframe/propulsion integrated configuration. The purpose of this research is to find a proper configuration for a horizontal take-off and horizontal landing Suborbital Reusable Launch Vehicle (SRLV) powered by Rocket Based Combined Cycle (RBCC) engine. The mission of this SRLV is to deliver 20,000 kg payload to an altitude of 50km and a velocity of Mach 8, and to be able to fly back to the original launch site. However, there is scarce knowledge about how to select proper configuration. Here, four alternatives with different aerodynamic shape and flow path geometry are evaluated and down selected according to some goals in given mission. A design methodology with corresponding software toolset is developed for the comparison study of configurations. The methods include: 1) an integrated aerodynamic/propulsion analysis method with 3D NS solver for outer flow and 1D Euler solver for inner flow simulation; 2) a structural optimization method with FEM solver for structural analysis and sizing; 3) an thermal protection system optimization method with panel based aero-heating analysis and 1D finite differentiation heat conduction analysis for TPS sizing; 4) a trajectory optimization process with gauss-pseudospectral method for mission and performance analysis. Takeoff gross weight and dry weight of each configuration are evaluated. The results show that the configuration of lift-body airframe installed with dual RBCC flow path on both side has smallest dry weight, while the configuration of lift-body installed with single engine on abdomen has smallest takeoff gross weight.