PROBLEM TO BE SOLVED: To provide an axial-flow fluid machine which suppresses separation of a fluid flow in a front edge or an outer peripheral part of a blade of an axial-flow impeller by making appropriate drift at the front edge and in the vicinity of the outer periphery of the blade and shapes of the front edge and outer peripheral part of the blade, and prevents decline in efficiency and static pressure increase, vibration and noise. SOLUTION: In the axial-flow fluid machine, the axial-flow impeller 10 is arranged inside a casing 22. When an intersection point A of a boss 11 and an upstream side edge of the blade 12 is defined as a starting point and an intersection point B of a vertical face extended from an inflection point 23 of a suction bell mouth 21 to the radial direction and the outer periphery of the blade 12 as a terminal point, an edge smoothly connecting the starting point (intersection point A) and the terminal point (intersection point B) by a free-form curve is defined as the front edge 13 of the blade 12. The shape of the front edge 13 is determined so as to be suitable for an inflow situation of fluid flowed from outside into the suction bell mouth 21, and in the downstream side from the terminal point (intersection point B), a wall face of the casing 22 is set to be approximately parallel with the outer periphery of the impeller 10. COPYRIGHT: (C)2008,JPO&INPIT

Okamoto Hidenobu

Papers

Axial-flow fluid machine