Jacques Thebault

Fully Ceramic Composite Heat Exchanger Qualification For Advanced Combustion Chambers

In the continued development of hypersonic propulsion systems, within the frame of the A3CP (Advanced Composite Combustion Chamber) program, Snecma and Onera have jo intly developed and tested a light, fully leak-free, composite heat exchanger technology. This paper presents the last qualification steps performed. These include the implementation of a test sample in the Onera ATD5 scramjet test rig, for the performance of eight short duration Mach 7.5 test cycles, and the evaluation of another sample for longer duration tests.

Composite Technologies Development Status for Scramjet

Since 1998 Snecma Propulsion Solide is working to demonstrate the interest of using of carbon – carbon and carbon – silicon carbide composite materials in a scramjet combustor. Through the cooperation between UTC and SNECMA, weight savings and increased thermal margins relative to an all – metallic scramjet were shown by using uncooled part in carbon-silicon carbide composite material. Moreover a USAF-DGA cooperation, the AC3P (Advanced Composite Combustion Chamber Program), funded the development of a C/SiC actively cooled technology as a potential future replacement for the current HySET metallic design. Several panels were manufactured and tested in parallel to a material and structural development study. Initial tests in the USAF AFRL radiant facility de monstrated a SNECMA manufactured totally leak-free composite heat exchanger in relevant conditions. Since then, other tests were performed in ONERA French facilities on this technology. This paper presents the development status of scramjet applicable technologies at SNECMA and the foreseen future developments.

Non Thermal Plasma Functionalized 2D Carbon–Carbon Composites as Supports for Co Nanoparticles

AbstractNovel two-dimensional carbon–carbon composites made of carbon nanofibers (CNFs) supported on a carbon preform were functionalized by non thermal plasma treatment (room temperature, atmospheric pressure, humid air), before being used as supports for metallic cobalt nanoparticles. It was shown that the degree of functionalization of the carbon nanofibers depends on the plasma power input, the treatment time and the CNF loading. The size of the cobalt nanoparticles generated after subsequent reduction of the Co-containing plasma treated CNF/C composites under hydrogen flow seems to be independent of the amount of supported cobalt. Changes in surface characteristics were analyzed using thermogravimetric analyses coupled to a mass spectrometer, X-ray photoelectron spectroscopy analyses and Raman spectroscopy. Transmission electron microscopy was used to complementary characterize the final size, dispersion and location of the so generated Co nanoparticles.