| 摘要 |
The diffuser is symmetrical about an axis AA' and has a flared outer wall (2,3) going from an axial inlet to an outlet. The outer wall is divided into an upstream portion (2) and a downstream portion (3) by a circular bleed slot (1) disposed symmetrically about the axis. The profile of the outer wall is such that, in operation, the direction of fluid flow along the outer wall is from the inlet towards the outlet, both over the upstream portion, and over the downstream portion. Further, it is so arranged that the pressure gradient measured at the surface of the wall and along the direction of fluid flow is negative upstream from the bleed slot and positive downstream therefrom. This ensures that only a small percentage of the fluid flow needs to be bled off to achieve desirable flow conditions, thereby providing good diffuser efficiency. |
