| 摘要 |
PURPOSE:To restrain surging and improve efficiency by injecting a high pressure fluid into the exit portion of a diffuser, squeezing the passage width of the exit portion, and at the same time regulating the injection amount of the high pressure fluid according to the opening of a guide vane that regulates the suction flow of an impeller. CONSTITUTION:Between a pair of side walls 2, 3 arranged face to face mutually on the discharge side of an impeller 1, a fluid that has flowed in from the impeller 1 is introduced into a scroll 4 and a diffuser A is formed. In this case, at least one side wall 2 that forms the exit portion A2 of the diffuser A, an injection portion B1 to inject a high pressure fluid in a direction that intersects the fluid, and a pressure source B6 to supply the high pressure fluid are equipped, and a high pressure fluid exit squeezing means B to squeeze the passage width of the exist portion A2 by means of the high pressure fluid is provided. Also, a vane opening dependent injection amount control means C to regulate the injection amount of the high pressure fluid according to the opening of a guide vane 16 that regulates the suction flow of the impeller 1, is provided. As a result, the restraint of surging and the improvement of efficiency are attained. |
