The subject of this paper is the validation of the newly developed booster bleed valve control logic, which has been implemented into the new BR715 turbo fan jet engine.

The booster compressor is protected from surges in the low power regime as well as during transient operation by opening a booster bleed valve. This bleed valve is situated just after the booster compressor and passes bleed air into the bypass duct, hence unloading the booster compressor in critical operational conditions. The BR715 jet engine takes advantage of a newly developed logic driving this valve. Monitoring input parameters such as spool and flight speeds as well as altitude, the combined steady state and transient logic provides the capability of appropriately positioning the valve. This ensures maintaining an optimum performance of the engine throughout the whole operating range. Furthermore the logic allows for reaction on special requirements such as surge events.

During testing for certification of this engine, extensive handling tests have been performed. The performance of the logic was investigated in detail and the results are documented within this paper. They prove the logic to be working very successfully. The booster compressor is totally protected from surge in the low power regime during steady state conditions. For transient operation, especially during rapid decelerations as well as during bodie manoeuvres of the engine, the core logic for the transient modulation showed extremely effective behaviour.

The various schedules inside the logic were partially varied for testing. This paper comprises this development process and each table’s contribution to the booster compressor’s behaviour is explained in detail.

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