Rolls-Royce to Begin Unblended SAF Tests

With the intense focus of the aviation industry on the lowering of its carbon footprint, Rolls-Royce is looking ahead to the day when sustainable aviation fuel (SAF) becomes more widely available and will begin exploring the use of 100 percent SAF on one of its engines this week.

The powerplant maker will conduct ground testing with one of its Trent engines on a stand at its Derby, UK test facility, using SAF produced by World Energy in California and delivered by SkyNRG.

The program is aimed at determining how the company’s current engine designs operate on “neat” or unblended SAF and what future modifications could benefit them. According to Simon Burr, the company’s director of product development and technology, Rolls-Royce will induct an engine from its Pearl family—which powers the in-flight-test Gulfstream G700 and Bombardier Global 5500 and 6500—into the 100 percent SAF test program in the new year at its Germany location. “I would just say I am less worried about relight and the operability of the engine,” Burr told AIN. “I don’t think those things are a major consideration, it’s mainly the issue of [fuel system] sealing in particular that is the prime anxiety.”

Currently, to be considered a drop-in replacement for standard jet-A and to meet the specification for ASTM D7566, SAF must be blended to ensure the presence of proper amounts of aromatic compounds, which are generally lacking in neat SAF.

Burr noted that in the company’s modern engines, nitrile seals have been supplanted with those made from synthetic materials such as fluorocarbon and fluorosilicon, which are unaffected by aromatic content. “I’m confident the fuel we’re testing would work quite happily on all our current engines,” he said, adding that he would expect to soon see an airframer such as Gulfstream announce a test flight on 100 percent SAF.

“But we have to support our engines going back decades and so we have to be diligent and say, 'What would we require if we want to run 100 percent SAF on an engine that was built 30 years ago?'" As the test program continues, Rolls-Royce will continually reassess the status of the market to decide if it needs to begin back testing its legacy engines.

The Trent engine selected for the test is equipped with the manufacturer’s new ALECsys (advanced low emissions combustion system), part of its UltraFan next-generation high-bypass ratio engine demonstrator program that is anticipated to offer a 25 percent fuel savings over the standard Trent. Burr insists that the test results, which Rolls-Royce will share, will be applicable to regular engines. “Just to be clear, the test has nothing to do with the combustion system, it just happens we’ve got an engine test vehicle with very sophisticated emissions measurement on it, so we’re using that.”

With the total SAF available at present only equating to 0.1 percent of global jet fuel production, but with aspirations to boost that level to 2 percent in the coming decade, Burr acknowledged that these tests are looking out over the horizon, in terms of furthering the industry’s goals as well as Rolls-Royce’s own efforts, even as the world remains fundamentally changed. “Covid squeezes every budget,” he said. ”The fact that we’re doing this tells you that we regard it as important.”

Production with high value, while saving fuel, is also the development trend of our country's engines. Under this background,the 5th Commercial Aero Engines Shanghai International Forum will be held in Shanghai from March 24th-25th, 2021. Focusing on scientific and technological innovation-driven, integration of industry in-depth, the forum invited a number of domestic and foreign aero engines and aircraft host development units.

The following is the hot topics:

· The aviation industry policy and market trends under the 14th Five-Year Plan

· Aero engine simulation technology

· Advanced test and test technology for aero engines

· Advanced aero engine materials and processing technology

Click here to register you interest or contact with Sara directly.