Testing of DLR C/C-SiC and C/C for HIFiRE 8 Scramjet Combustor

Abstract

Ceramic Matrix Composites (CMCs) have been proposed for use as lightweight hot structures in scramjet combustors. Previous studies have calculated significant weight savings by utilizing CMCs (active and passive) versus actively cooled metallic scramjet structures. Both a carbon/carbon (C/C) and a carbon/carbon-silicon carbide (C/C-SiC) material fabricated by DLR (Stuttgart, Germany) are being considered for use in a passively cooled combustor design for Hypersonic International Flight Research Experimentation (HIFiRE) 8, a joint Australia / Air Force ResearchLaboratory hypersonic flight program, expected to fly at Mach 7 for ~30 sec, at a dynamic pressure of 55 kPa. Flat panels of the DLR C/C and C/C-SiC materials were installed downstream of a hydrogen-fueled, dualmode scramjet combustor and tested for several minutes at conditions simulating flight at Mach 5 and Mach 6. Gaseous hydrogen fuel was used to fuel the scramjet combustor. The test panels were instrumented with embedded Type K and Type S thermocouples. Zirconia felt insulation was used during some of the tests to reduce heat loss from the back surface and thus increase the heated surface temperature of the C/C-SiC panel ~177°C (350°F). The final C/C-SiC panel was tested for three cycles totaling over 135 sec at Mach 6 enthalpy. Slightly more erosion was observed on the C/C panel than the C/C-SiC panels, but both material systems demonstrated acceptable recession performance for the HIFiRE 8 flight. NomenclatureER = Equivalence Ratio FUEL1P = Fuel Supply Pressure M = Mach number P = Pressure P 0 = total pressure PTOTAL1 = Facility Total Pressure q dot = heat flux T = Temperature T t = Total temperature T w = Temperature at wall surface x = distance from the facility nozzle exit plane (exit of the ramjet inlet)  H2 = equivalence ratio of injected hydrogen fuel

Thermal protection tile structures of shuttlecraft with different external load-carrying elements

“…Panels from such materials are used in TPSs of ISV SHEEFEX, PH HIFiRE 8 and IXV demonstrator [5]. Manufacturing CCCM structures is a lengthy and expensive process.…”

Carbon-carbon combustor for prolonged hypersonic flight: Developing and validating predictive manufacturing and design methods for ultra-high temperature composite assemblies

“…The absence of core rotating turbomachinery allows for significantly higher cycle temperatures in scramjets (as noted from Table 1), albeit at the requirement of combustor materials with sufficient mechanical and thermal properties to withstand severe and prolonged thermal environments [1]. The implementation of ultra-high temperature composite assemblies in scramjet combustors, such as CMCs, has the potential for significant system performance improvements [5]. However the design, manufacture and modelling of such ultra-high temperature composites has become a critical limiting factor in the prototyping of scramjet test vehicles, and thus is a key contributor to the development of an air-breathing hypersonic platform.…”

“…The three primary UHTCs of interest for aerospace applications are carboncarbon (C/C), carbon-carbon silicon-carbide (C/C-SiC) and carbon-carbon tantalum (C/C-Ta) ceramic matrix composites (CMCs) [5]. CMCs exhibit high strength, low density, wear resistance, excellent high temperature capability, good corrosion resistance and far superior damage-tolerance and thermal shock resistance to conventional monolithic ceramics [18] [19].…”

“…As such, both actively and passively cooled CMCs exhibit significant weight savings over stateof-the-art actively cooled metallic ultra-high temperature assemblies for short duration and single-use prototype combustors, such as the HIFiRE 8 flight vehicle [5]. C/C composites may be manufactured via chemical vapour deposition (CVD), thermoplastic precursors or thermoset precursors.…”

“…For example, the implementation of UHTC ceramic matrix composite (CMC) high pressure turbine stages has allowed civilian gas turbine engines to minimise cooling flow and reduce emissions; similar technology is of interest in the fabrication of supersonic combustion ramjet (scramjet) combustors [1]. UHTC development has been motivated by unmet materials needs in the aerospace sector for wing leading edge components, propulsion systems and atmospheric re-entry and rocketry, however in order for UHTC implementation to be viable, cost-effective and automated mass manufacturing methods as well as accurate material design allowables data is mandatory [5] [6]. Filament winding, a process of winding unidirectional fibre and resin over a mandrel, meets the criteria for mass manufacture in the aerospace sector albeit at the requirement of closed form and efficient methods for determine elastic and mechanical properties of UHTC assemblies manufactured in this manner [7].…”