CompositesWorld
Issue link: https://cw.epubxp.com/i/546021
AUGUST 2015 38 CompositesWorld By Ginger Gardiner / Senior Editor Aeroengine Composites, Part 1: The CMC invasion As pressure for commercial aircraft fuel efciency continues to mount, ceramic matrix composites evolve as they battle metals for application in the engine hot-zone and elsewhere. » Te airlines' push for jet engine fuel efciency shows no signs of abating. CW reported earlier this year that the average fuel burn per aircraft seat-km today compared to 1980 has been reduced by 27% for widebody aircraft and 35% for narrowbody models (see "Learn More." p. 34). But more ambitious reductions have been called for by the Advisory Council for Aviation Research in Europe (ACARE) in Flightpath 2050 — a 75% reduction in CO 2 per passenger-km, a 90% reduction in nitrous oxide (NOx) emissions and a 65% reduction in noise by the year 2050 vs. performance levels recorded in 2000. Te dire need for, and rather drastic depth of, such reductions are precisely the sort of situation where the subject of this report, composite matrix composites (CMCs), promise a solution. Although they're considerably more expensive — reportedly hundreds to thousands of dollars per kilogram — they are roughly one-third the weight and twice the strength of the nickel alloys currently used in jet engines, and they ofer a 100-200°C improvement in high-temperature capability. No surprise, then … they're now in demand. Engine application landscape Notably, carbon fber reinforced polymer (CFRP) composites (the subject of Part 2, which will appear in CW September) continue on an upward growth curve, but CFRP and CMC growth trajectories are on something of a collision course. According to Henrik Runnemalm, director of advanced engineering for Tier 1 Combustor Fan Blade High-Pressure Compressor Low-Pressure Turbine High-Pressure Turbine Low-Pressure Compressor Spinner FIG. 1 CMCS: Forward & outward A cross-section of GE Aviation's (Cincinnati, OH, US) GE90 turbofan engine, the frst to use CFRP fan blades in service. Today, the use of CFRP is increasing from the cooler front fan and outer applications toward the hotter rear and inner sections. For CMCs, however, the evolutionary growth path is in the opposite directions, forward, from hotter to cooler zones, and from inner to outer structures. Source | GE Aviation (text added by CW)