Patent ID: 9657573
Date: 2017-05-23
CPC Classifications: F01D,F05D

Claim:
1. A mixed flow turbine comprising: a turbine rotor having a front edge, through which a fluid flows in, the front edge being shaped so that a middle portion thereof between a hub side and a shroud side is formed so as to protrude toward an upstream side past a line extending between the hub side and the shroud side; a turbine housing formed to cover the turbine rotor and having a scroll portion for supplying the fluid toward the front edge of the turbine rotor; a scroll partition wall dividing the scroll portion into a shroud-side space and a hub-side space; a shroud-side inflow passageway formed between a shroud-side partition wall surface on an inner periphery side of the scroll partition wall and a portion opposing the shroud-side partition wall surface, the fluid flowing through the shroud-side inflow passageway in a generally radial direction to a shroud-side inlet of the turbine rotor; and a hub-side inflow passageway formed between a hub-side partition wall surface on an inner periphery side of the scroll partition wall and a portion opposing the hub-side partition wall surface, the fluid flowing through the hub-side inflow passageway in a direction generally equal to an inclination direction of a hub to a hub-side inlet of the turbine rotor, the turbine rotor comprising: a plurality of main blades formed to stand upright in a circumferential direction on a hub outer circumferential surface, and having a height spanning an entire extent between the hub outer circumferential surface and an inner periphery surface of a shroud portion; and a plurality of intermediate blades each of which is arranged in the circumferential direction between two of the main blades so as to extend from an inlet portion to an intermediate portion with respect to the extension of the main blades, and has an intermediate height with respect to the height of the main blades, the fluid from the hub-side inflow passageway being allowed to flow in through a front edge of each of the intermediate blades, wherein the front edge of each of the plurality of intermediate blades coincides with a front edge of a corresponding one of the plurality of main blades, while a blade height of the front edge of each of the plurality of intermediate blades is set to a position substantially equal to, or higher than, a center line on a meridional plane that divides a flow along the main blade into passageway areas of a flow through a shroud-side passageway and a flow through a hub-side passageway on a basis of a ratio between the passageway width of the shroud-side inflow passageway and the passageway width of the hub-side inflow passageway, and a blade height of a rear edge of each of the plurality of intermediate blades is set to a position higher than a blade height of the front edge of the intermediate blade.