| 摘要 |
<p>PURPOSE:To prevent the boundry layer of airflow from being detached from the wall surface by extending the circumferential edge of impeller back plate from the outer edge of the impeller vane to the direction of vaneless diffuser. CONSTITUTION:The back plate surface 24 is formed by extending the impeller back plate 22 from the outer end 7 of impeller vane 2 to the vaneless portion 23 in radial direction. The airflow, generated from the outer end 7 of impeller vane 2 due to centrifugal force, flows to the radial direction along the back plate surface 24, and decelerated due to the expanded flow passage area. Accordingly, abrupt change in static pressure is alleviated. With the back plate 24 provided as stated above, the airflow is guided along the back plate 24 so that the abrupt change in static pressure is eliminated and formation of airflow boundary layer is supressed. As a result, the boundary layer of airflow is prevented from being detached from the wall surface 25.</p> |
