IMPELLER FOR CENTRIFUGAL COMPRESSOR

摘要

PROBLEM TO BE SOLVED: To improve the efficiency of a centrifugal compressor, and to widen the operation range thereof by appropriately setting an inlet blade angle of an inducer part on the basis of the speed distribution of an impeller inlet to be decided in response to the shape of an inlet duct. SOLUTION: The inlet blade angleβformed by a rotary shaft 11 and the inducer part 7 on a cylindrical expansion surface of a blade 5 is set to satisfy the relation that tanβ=(1/ε)tanβd when expressing a value of a ratio V/Vd of the axial directional speed V of the air at a desirable radius R position between a hub diameter and a tip diameter in relation to the axial set speed Vd of the air at a set point between the hub diameter and the tip diameter withε(V means a parabolic function of R,εis set to satisfy an expressionε>1 at the and 1>ε>0 at the hub) and expressing an inlet blade angle of the inducer part 7 at the described set point withβd.