Advanced carbon/carbon injection strut for actual scramjet

Scramjet engines for airbreathing space launchers have to use injection struts in order to feed all the combustor duct with hydrogen. These struts complete the air intake compression, help the ignition if necessary, stabilize the combustion and enhance the mixing. They must afford heat flux up to 100 MW/m2, because of the hard conditions of incoming air and the small leading edge radii used to minimize the flowfield pressure losses. In the scope of internal R&D, AEROSPATIALE has developped a project called SAINT-ELME (French acronym for Advanced System of Injection for High Mach Number Flows) to design, manufacture and test a carbonlcarbon injection strut designed for Mach 6 to 12 operations. The size of the strut is compatible with the AEROSPATIALE's CHAMOIS scramjet model. Ramjet specialists from AEROSPATIALE Bourges and composite specialists from AEROSPATIALE Aquitaine have worked together for more than 2 years on the SAINT-ELME project. The hydrogen-fueled-cooled protected carbodcarbon strut is now available, and the deep studies and tests have proved that : the leading edge of less than 2 mm radius can afford Mach 12 conditions, the composite strut is at least two times lighter than a metallic one, the use of high temperature material could allow hydrogen injection temperature over the classical value of 1000 K, to increase the effective Isp of the scramjet by enthalpy and momentum effect. Several significant work has also been done on carbonlcarbon technologies to achieve this result. Copyright 1996 by AEROSPATIALE. Published by the American Institute of Aeronautics and Astronautics, Inc with permission.