Patent ID: 8616843

Claim:
Turbo machinery comprising an impeller and a diffuser positioned on a downstream side of the impeller, a channel wall surface of the diffuser being composed of a pair of a shroud side diffuser plate and a hub side diffuser plate which surface each other and a channel width is formed so as to be increased downstream, characterized in that guide vanes in a circular arc shape lower in height than the channel width are installed in a line of a plurality of vanes on both channel walls of the shroud side diffuser plate and hub side diffuser plate of the diffuser, and a total of vane heights of the two guide vanes at an outlet of the diffuser is set so as to be within a range from 30 to 70% of the channel width at the outlet of the diffuser, and assuming an inclination angle of the channel wall surface of the shroud side diffuser plate in a radial direction as Î¸ s , a vane inlet angle of the guide vane installed on the wall surface of the shroud side diffuser plate in a peripheral direction at the inlet as Î² s, in , an inclination angle of the channel wall surface of the hub side diffuser plate in the radial direction as Î¸ h , and a vane inlet angle of the guide vane installed on the wall surface of the hub side diffuser plate in the peripheral direction at the inlet Î² h, in , respectively, said four angles set conform to a following formula (1), Î² s in âˆ’Î² h in =K (Î¸ s âˆ’Î¸ h ) 0 (1) and K of the formula (1) is set so as to conform to a relation of K<0.