Abstract
One of the key points for the development of dual-mode ramjets operating up to Mach 8 or more is the mastery of fuel-cooled composite materials structures, which are needed, at least, for the combustion chamber. MBDA France and EADS ST have been working on the development of a particular technology for such structures taking advantage of the background of MBDA France in the field of dual-mode ramjet and fuel-cooled structures and of EADS ST in the field of high-temperature composite materials. In a first step, several cooled panels, obtain by Vapor Chemical Deposition process, had been successfully tested at MAI in Moscow. By another a U-shaped part has been developed in order to demonstrate the feasibility of a complete combustion chamber in a single part. A large activity has been also led to characterize the obtained materials from the point of view of mechanics but also of permeability considering that the ability to control the porosity of the cooled structure skin is a key point for the feasibility of such fuel-cooled structure of combustion chamber. In order to try to decrease the cost while controlling the permeability of the structure, the Liquid Silicon Infiltration process has also been evaluated. After 2004 good results and process optimisation, LSI is now the reference process for the years to come. Good mechanical properties of skin were achieved, because yarns are not damaged after siliconizing with the chosen process,. This chosen process is based on Rapid-Chemical Vapor Infiltration before LSI and then deals with short densification time (a few days instead of weeks for CVI). This current technology phase was achieved in 2005 with the manufacturing for scramjet test of subscale actively-cooled complete ducts (called PSD for “Ptah-Socar duct”). Further investigation was done for use on DMR with densification process optimization, system studies, complementary testing, definition of a technology demonstrator. Detailed mechanical characterisation was performed, including burst test (existing panelare not broken after 2 times the nominal operating internal pressure), skin tensile and shear test of skins, compression, shear and flexure test of sandwiches. Several mechanical modelling were performed, from advanced study level up to detailed Finite Element Method analysis. This analysis has been applied on elementary samples, on PSS panel and on PSD complete duct. It can be applied for the design of actual engine structures, either 2D or axisymetric. Hot test of LSI panel (PSS3) was realized at the exit of a scramjet, with preheated air or kerosene as coolants. PSS3 afford burst test up to 80 bar of internal pressure, then more than 10 hot runs. Permeability change test after test was confirmed has before, with increase of cold leakage with air test and decrease with kerosene-cooled experiment when coking occurs in the skins. The level of leakage is close to the measurement accuracy. On the acquired technology base, some system studies have been performed to prepare new test series and to better demonstrate the interest of the PTAH-SOCAR technology for both dual-mode ramjet combustor and liquid rocket combustor applications. Since 2004, application to other systems such as Liquid Rocket Engines has been indeed more deeply considered. This work is a cooperative effort between MBDA France, EADS-Space Transportation in Ottobrunn and Bordeaux, EADSCommon Research Center in Ottobrunn and Suresnes, with some laboratories and subcontractors. The paper gives an updated status of the development of PTAH-SOCAR technology, including test results, and present s some results obtained during system studies both for DMR and LRE.
Published Version
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