CompositesWorld
Issue link: https://cw.epubxp.com/i/546021
AUGUST 2015 40 CompositesWorld MARKET OUTLOOK At Rolls-Royce (Manchester, UK), researchers tested SiC-SiC HP turbine blade tracks in 2013 and then SiC-SiC shroud segments, using a Trent 1000 test engine via the Environmentally Friendly Engine (EFE) program. Te blade tracks — which could reduce component weight and engine cooling by 50% — also were key demonstrators in the US Federal Aviation Admin.'s (FAA, Wash- ington, DC, US) Continuous Lower Energy, Emissions, and Noise (CLEEN) program. Testing is scheduled to run through 2015. Te higher pressure ratios planned in Rolls-Royce's Advance and UltraFan engines mean higher operating temperatures and increased NOx emis- sions — increases that could be miti- gated through the use of CMCs. Te company says it will defnitely use CMCs in static parts, such as nozzles, and in its Vision10 (technology- ready in 10 years) strategy outline, its HP turbine goes shroudless, using, instead, a CMC liner. Pratt & Whitney (Hartford, CT, US) has said it sees low value for CMCs in static applications and, there- fore, will focus CMC application eforts on rotating turbine blades and the combustor. In 2010, Pratt & Whitney Canada (P&WC;, Longueuil, QC, Canada) tested a CMC reverse-fow combustor in a PW200-series rotorcraft engine, achieving a 30% NOx reduction at high power and a 20% cut in CO at low power vs. the standard metal unit. Patent application US 2014/0311152 A1 describes the annular combustor as having an inner liner comprising a dome portion, a small exit duct portion and a large exit duct portion, each an independently formed hemi-toroidal CMC shell. Although the combustor sees the highest temperatures in this engine, holes for cooling air delivery are not necessary, so no machining is required after liner sections are formed. In 2015, P&WC; presented results from computer analysis of thermal stresses on a combustor molded with Ox/Ox materials from COI Ceramics (San Diego, CA, US). It analyzed fat and curved segmented panels as well as 360° annular parts and iden- tifed potential for delamination at temperature transitions and panel edges, tensile rupture on the cool side, and compressive damage accompanied with fber buckling on the hot side and panel edges. However, adding an insulation layer reduced stresses by a factor of three. Upping performance at the exit Herakles (Le Haillan, France), a subsidiary of Paris, France- based Safran, has been working on a series of CMC parts for the next generation of LEAP engines as well as new Safran-designed engines targeting the 2020-2030 timeframe. On June 16, it announced that its SiC-based exhaust cone (see "Learn More") is the frst CMC part to fy on a jetliner in commercial service. Fastened directly to the aft fange of the CFM56 test engine's turbine frame, and interfaced with the nacelle, the exhaust cone comprises a centerbody and a complex "lobed" shape mixer. Te latter achieves optimal mixing of the hot engine gases with the cold bypass air, improving the engine exhaust system's output and efciency (see Fig. 3). Measuring 1,625 mm in length and 655 mm in diameter, the exit cone weighs a mere 24.5 kg. European Aviation Safety Agency (EASA, Cologne, Germany) certifcation for use on commercial fights slated for 2013 was fnally received April 22, 2015. Te company has completed demonstrations of other new commercial aeroengine applications: • Prototype CMC mixers ground-tested on a CFM56-5C engine and fight-tested on an Airbus Helicopter (Marignane, France) Tiger rotorcraft. • In-fight test of a CMC trailing-edge fairing on an A380 engine pylon. • CFM56 engine ground-test of CMC LP turbine blades. FIG. 4 CMC mixer Composites Horizons will produce the Ox/Ox CMC mixer, which cuts 20 kg from the GE Passport 20 engine. Source | CW FIG. 3 CMC exhaust cone The ARCOCE (ARrière-Corps Composite CEramique, or afterbody ceramic composite) engine exhaust cone is the frst to fy in commercial sevice. Source | CW Read this article online | short.compositesworld.com/Jet1-CMCs Read CW's earlier coverage of this market online in "Composites in commercial aircraft engines: 2014-2023" online | short.compositesworld.com/MO-AeroEng Read more about CMCs in "Ceramic matrix composites heat up" online | short.compositesworld.com/WrsprzMm Read more online about Herakles' CMC exhaust cone in the CW Blog titled "Highlights: JEC Europe 2014" under the heading "CMC exhaust cone for LEAPX engines" | short.compositesworld.com/JEC14Blog