A cooled structure for a conceptual dual-mode ramjet will be tested shortly as part of ongoing joint research by European missile company MBDA. The project, with EADS's research arm Innovation Works and its space company Astrium, aims to develop a carbon silicon carbide (C/SiC) propulsion system fabrication process.
Called Paroi Tissee Application Hypersonique (PTAH) Simple Operational Composites for Advanced Ramjet (PTAH-SOCAR), the ultimate goal is to manufacture C/SiC whole structures, such as a combustion chamber.
Paroi Tissee, or "woven wall", describes the use of weaved carbonfibre to produce the shape of the structure wanted. That pre-form then goes through a densification process, which increases the amount of carbon in the pre-form, and as fibrous structures are permeable a sealant application process is used to seal the pre-form. Between each step x-rays or neutron tompgraphy is used for non-destructive testing.
As well as producing structures able to withstand an engine's high-temperature environment, the PTAH-SOCAR manufacturing process can incorporate cooling channels into the weaved pre-form. Metal structures have to have cooling channels machined into them.
"We get a 30% reduction in weight [for any structure] against metallic structures and limited geometry changes due to the heat," says MBDA's head of hypersonic research, Marc Bouchez. He adds that there could be cost benefits in using PTAH-SOCAR structures instead of metal as well. Other structures being investigated for PTAH-SOCAR are heat exchangers, transpiration cooling, and liquid rocket engines.
MBDA and EADS are also working on the technology for the European Union's aerodynamic and thermal load interactions with lightweight advanced materials for high-speed flight (ATLLAS) project. Under ATLLAS axisymmetrical duct structures operating in high pressure kerosene/oxygen environments will be tested.
Source: Flight International
