Development study of the ATREX engine for TSTO spaceplane

An expander cycle air-turbo ramjet (ATREX) engine has been developed in the Institute of Space and Astronautical Science (ISAS). The ATREX will be used from lift-off up to Mach 6 as the propulsion system of the fly-back booster of TSTO spaceplane. This report indicates the present status of studies and key technologies to solve on the ATREX. Flight tests using a demonstration engine are necessary in order to get engine data over wide and unsteady flight conditions. The total engine system and components have been re-considered according to current and near term technologies and materials. For example, the turbo machine configuration is changed, namely, the turbine is placed behind the fan instead of the present tip turbine. A ram combustor test was conducted with six mixers for the new flow passage. Catalytic igniters were tried and could make the global combustion when the igniter temperature was more than 450K. Some devices to reduce the frost formation on a precooler were tested. Addition of a small quantity of methanol with the incoming air can effectively restrain the frost formation. Application studies of carbon/ carbon composites to a turbine ring and a heat exchanger has been conducted. Basic studies are continued to make complicated shapes, to protect leakage and oxidization.