An innovative technology for fuel-cooled composite materials structure

One of the key points for the development of hypersonic airbreathmg propulsion is the mastery of fueled-cooled composite materials structures which are needed for realizing the combustor of a dual-mode ramjet operating up to Mach 8 or more. Very limited activities have been led by EADS France and SNECMA on this subject during the PREPHA program with basic test performed at ONERA. In the same time, EADS France developed a carbon/carbon hydrogen cooled injection strut, which has been successfully tested in CHAMOIS scramjet chamber. By another way, the cooperation led by EADS Aerospatiale Matra Missiles (EADS-AMM) and the Moscow Aviation Institute for developing a fully variable geometry dual mode ramjet was also an opportunity to acquire a large know-how in the field of fuel-cooled structures. Beyond these first steps, EADS-AMM and EADS Launch Vehicles (EADS-LV) are now working on the development of an innovative technology for fueledcooled combustor structures taking advantage of EADS-LV mastery of specific weaving process for manufacturing composite materials. By comparison with the « classical » technology of assembled cooled panels, this technology will allow to limit the connecting problems, improve the mechanical characteristics and reduce the mass and the cost. The PTAH-SOCAR technology was the subject of a first successful hot test in the MAI test facility. A followon experimental program should complete the demonstration of the fuel-cooled panel technology feasibility while a preliminary design of a PROMETHEE combustion chamber should allow to precisely evaluate its interest from the point of view of the system conception. Copyright © 2001 by EADS Aerospatiale Matra Missiles and EADS Launch Vehicles. Published by the American Institute of Aeronautics and Astronautics, Inc, with permission. Introduction EADS Aerospatiale Matra Missiles (EADS-AMM) has been a major contributor, beside ONERA, to the National Research and Technology Program for Advanced Hypersonic Propulsion PREPHA (Ref[1]). Within the scope of this program, EADS-AMM acquired a first know-how in scramjet and dual-mode ramjet components design and hypersonic airbreathing vehicle system studies. On this base, the present activity, led in cooperation with ONERA, is mainly focused on the development of the dual mode ramjet technology (Ref[1] and [2]). From the point of view of materials, the major technological difficulty for the development of hypersonic airbreathing vehicles, powered by dualmode ramjet or scramjet, is to design and realize the structure of the combustion chamber. Indeed, the combustion chamber and the fuel injection and/or flame stabilization systems, possibly placed in the flow, must be able to sustain a rarely so severe thermomechanical environment. Moreover, it is possible that the operational use of the airbreathing propulsion on a very large range of Mach number (Mach 2 to Mach 8 for military application, at least Mach 2 to Mach 10 for space launcher application) will imply a variable geometry for the combustion chamber. It supposes to have on disposal structures with sufficiently controlled geometry to ensure tightness between movable and fixed surfaces of the chamber. By another way, working at high wall temperature limits the thermal loading, particularly during a high-speed cruise phase. That is very favorable for military application if we consider the limited cooling capacity of a hydrocarbon fuel even if it is endothermic. That is also very favorable for space launcher application (with hydrogen as fuel) for extending at the maximum the use of the installed airbreathing propulsion system. Finally, having large design margin allows to use relatively low cost cooling systems while ensuring good reliability and safety characteristics. c)2001 American Institute of Aeronautics & Astronautics or Published with Permission of Author(s) and/or Author(s)' Sponsoring Organization.