| 摘要 |
Cooling air 41 is bled from a compressor 12 and is then passed through a diffuser 30 that reduces the pressure of the cooling air 41 below that required at entry to the turbine stage 36. The air 41 is then re-pressurised by being passed through a space between the downstream face of the turbine disc 34 and a vaned 58 cover 44 which is close to, and rotates with, the turbine disc 34. The pressurised air then passes to the roots of the turbine blades via holes 60 in the rim of the disc. The diffuser 30 may be a radial turbine, or may be provided by a conical member (not shown) or external diffuser pipes (62, figure 3). |
