High Pressure Oxygen REGEN and Film Cooling for LOX/Hydrocarbon Reusable Engine

To meet IHPRPT goals for LOX/HC booster engines, improvements must be made in performance, thrust/weight, life, reliability, and cost. To date, operational LOX/hydrocarbon engines have used the fuel as the thrust chamber assembly (TCA) regenerativecoolant, and have used fuel film cooling (FFC) as the TCA hot gas wall protective layer. The present hydrocarbon fuels show increasing coking behavior at high chamber pressures (Pc) and heat loads, thus limiting their utility for long-life reliablesystems. In addition, some of the most attractive Advanced Hydrocarbon (AHC) fuels may not be suitable for TCA cooling due to limited thermal capacity or monopropellant tendencies. Schafer proposes an alternate path to the fuel cooling roadblock byincorporating LOX TCA regen cooling and ideally oxidizer film cooling (OFC) to reduce chamber hot gas side heat loads. Both FFC and OFC can be used to reduce wall thermal heat loads to acceptable values and, thus, will both be considered. However, OFCcoupled with LOX cooling provides greater robustness and safety, and completely de-couples the wall zone cooling behavior from the fuel characteristics. The proposed program will support the full-scale development of a high Pc LOX/HC engine adaptable toAHCs and satisfying Phase II IHPRPT goals. The development of this technology will enable the full-scale development of a high Pc LOX/HC engine adaptable to AHCs and satisfying Phase II IHPRPT performance goals and NASA requirements. The technology isapplicable to Air Force Hydrocarbon Boost program goals and can be adopted to commercial or government RLV and expendable launch vehicles.