今年4月中旬，世界首部完整GE9X航空发动机开始在通用电气航空集团(GE Aviation)位于俄亥俄州的皮布尔斯测试运行中心(PeeblesTesting Operation)进行地面测试。未来，这款发动机将登陆波音公司(Boeing)的新型777X航空客机。通用航空公司GE90/GE9X项目总经理Bill Millhaem表示，“地面测试可以创造大量有价值的数据，涉及完整发动机系统、空气动力学性能、机械校验以及航空热力系统校验等多个方面。”
据悉，GE9X涡扇发动机的成熟性测试始于大约5年前，目前已经从最早的元件级测试一路进行至最近的首次FETT测试（完整发动机测试）。FETT测试会集中GE9X发动机采用的各项技术，旨在展示这些不同模块作为一个完整推进系统的运行能力。
GE9X发动机在设计确认仅仅6个月后就开始了FETT测试，与大多数发动机相比，研发流程要快得多。通用电气表示，提早进行FETT测试可以保证测试中的任何收获都能完全反映在下一轮的发动机认证测试中。GE9X发动机的认证测试定于明年进行，届时还有将在通用航空公司的飞行测试床上进行的飞行测试。这款发动机的适航认证预计将在2018年开始。
据悉，多家公司均参与了GE9X航空发动机研发项目，其中包括石川岛重工(IHI Corporation)、斯奈克玛(Snecma)、赛峰集团（Safran）旗下航空航天技术公司(Techspace Aero)，以及MTU航空发动机集团(MTU Aero Engines AG)等。
赛峰集团旗下另一家公司埃塞(Aircelle)凭借为波音777X供应的钛材料发动机尾气系统，跻身波音公司的主要供应商之一。这款尾气系统将参与波音与通用电气两家公司的发动机合作研发项目。该尾气系统的尺寸很大，是同类型民用飞机中最大的。由于采用了同样也是基于钛材料的降噪解决方案，这款尾气系统的噪声水平明显更低。
由于埃塞公司采用了钛材料高温应用处理工艺，GE9X发动机的尾气系统不仅可以带来更高的质量效率，而且还具有更高的耐热性。埃塞公司优化了钛材料机舱元件的设计和制造，具体是利用公司的专业技能和专利数据库，对这种金属材料在尾气系统中的应用进行验证。埃塞公司不但专门斥资为777X项目升级了公司的生产资源，还与波音公司合作，以确保公司的生产流程完全合乎波音的生产要求。
目前，GE9X的订单已经累计到700台。这款发动机属于10万磅推力级别，前方涡扇的直径可达134英寸，带有一个复合材料涡扇套，以及16片用第四代碳纤维复合材料制成的涡扇叶。此外，这款发动机还采用了压缩比高达27:1的下一代11段高压压缩机、第三代TAPS III高效低排燃烧室，并在燃烧室和涡轮机中应用了CMC材料（即陶瓷基复合材料）。
作者：Jean L. Broge
来源：SAE《航空工程》杂志
翻译：SAE 上海办公室
Ground testing begins on the GE9X
In mid April, ground testing began on the first full GE9X development engine at GE Aviation’s Peebles Testing Operation in Ohio. The GE9X engine will power Boeing’s new 777X aircraft. According to Bill Millhaem, General Manager of the GE90/GE9X engine programs at GE Aviation, “The ground testing will generate data on the full engine system and aerodynamic performance, mechanical verification, and aero thermal system validation.”
Maturation testing of the GE9X turbofan engine began about five years ago and has progressed from component-level all the way to the recent first full engine to test (FETT). FETT brings all the GE9X technologies together to demonstrate their operability as a complete propulsion system.
The GE9X FETT began just six months after the engine's design was finalized, which is much earlier in the development process compared to most other engine programs. GE says this timing assures that everything learned from FETT will be captured in the certification engines. Next year will see the GE9X program starting certification testing and flight testing on GE Aviation’s flying test bed. Engine certification is anticipated in 2018.
IHI Corporation, Snecma and Techspace Aero (Safran), and MTU Aero Engines AG are just a few of the participants in the GE9X engine program
Another Safran company, Aircelle, is supplying titanium engine exhaust systems for the 777X, marking its first major role as a supplier to Boeing. The exhaust system is being used as part of the overall engine development program in partnership with Boeing and GE. These exhaust systems are among the largest of their type ever produced for civil aircraft, and include acoustical treatment areas, also of titanium, for a reduced noise level signature.
The exhaust systems on the two GE9X engines offer both mass efficiencies and increased resistance to heat primarily as a result of Aircelle's processes for titanium high-temperature applications. Aircelle has optimized the design and manufacturing of titanium nacelle components, applying its expertise and proprietary database in defining and validating the metal's performance for exhaust systems. The company has invested in new and upgraded production resources for the 777X program, while also working with Boeing in ensuring routines and procedures are fully compliant with its production requirements.
With almost 700 GE9X engines on order, the GE9X engine will be in the 100,000-lb thrust class and will have a large front fan 134-in in diameter with a composite fan case and 16 fourth-generation carbon fiber composite fan blades. Other key features include a next-generation 27:1 pressure-ratio 11-stage high-pressure compressor; a third-generation TAPS III combustor for high efficiency and low emissions; and CMC material in the combustor and turbine.
Author: Jean L. Broge
Source: SAE Aerospace Engineering Magazine
波音777X航空客机上搭载的两部GE9X涡扇发动机均将采用埃塞公司的尾气系统。由于采用了钛材料高温应用处理工艺，这两个发动机的尾气系统不仅可以带来更高的质量效率，而且还具有更高的耐热性。这款尾气系统的尺寸很大，为同类型民用飞机应用之最。由于采用了降噪解决方案，这款尾气系统的噪声水平明显更低。 
在法国勒阿弗尔工厂中，埃塞公司的员工正在对制造波音777X尾气系统所用的钛材料板（如图）进行激光切割，来自波音公司777项目机舱、供应商管理和研发功能团队的多名代表也在场观看。这款尾气系统将在波音与通用电气两家公司的发动机合作研发项目中使用。
波音的双发动机777X航空客机翼幅长达235英尺，可降低燃料消耗及单座平均运行成本。由于采用了碳纤维复合材料，这款航空飞机的机翼牢固又灵活，而且翼尖还可折叠，从而便利机场的管理工作。