30 October 2012

Trent XWB engine tests in extreme environment (hot and dusty conditions)

Airbus and Rolls-Royce are keenly aware that Qatar Airways and Emirates, two of the most outspoken and demanding airline customers for the A350 XWB, are watching flight-tests of the Trent XWB engine like hawks—particularly as the engine endures the heat and dust of recent flight trials in the Middle East (where sand and dust traditionally block seals and cooling holes in turbines).

At Al Ain in the United Arab Emirates, the latest test version of the engine for the A350-900 was brought for evaluation last summer under the wing of Airbus's A380 flying testbed.

The evaluation was a “good positive test because it proves the engine has margin in high ambient temperatures,” says Trent XWB program director Chris Young. “We put a lot of design features into the engine to make it tolerant to those conditions. Emirates and Qatar are key customers in the Middle East, so we are making the engine tolerant to those conditions,” says Young.

Bleed air off-takes, for instance, have been designed to ensure they scavenge a supply from the inner walls of the compressor rather than the outer walls. Dust particles tend to centrifuge to the outer walls, so positioning off-take valves on the inner walls places them in cleaner air. In addition, Young says, the cooling holes in turbines have been specially shaped to prevent particles from building up.
Overall, the engine has performed better than expected in terms of specific fuel consumption, says Young. Initial testing “took the engine around the whole envelope, including high angles of attack, and throttle-slamming. For that work the engine was kept around the Toulouse area. Then we put the higher-modification engine standard on the A380 and conducted the hot environment tests at Al Ain,” he notes.

Based on the article "Hot and Dusty" published in Aviation Week

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