| 摘要 |
In axial flow compressors of gas turbine engines it is well known to use either an air bleed valve 34 or a compressor casing treatment to improve the performance of the compressor. Air bleed valves act to keep the working line of the compressor close to the surge line. The casing treatment, which usually consists of one or more grooves 28 in the internal cylindrical surfaces adjacent the tips of a stage of upstream blades 22, acts to raise the compression ratio at which the rotor stalls. This invention combines the use of the bleed valve 34 with the grooves 28 to allow the bleed valve setting point to be reduced and ensure the bleed valve is closed at low power settings. <IMAGE> |
