PROBLEM TO BE SOLVED: To provide a novel blend round in which a cost and performance can be compatible with each other by setting specific dimensionless values R/O of a curvature radius R of the blend round with respect to a blade throat width O in sections between a rear edge of a blade and a throat, the throat and a branch point, and the branch point and a front edge of the blade. ;SOLUTION: A first section A from a rear edge 1a of a blade profile to a throat 4 is formed such that a dimensionless value R/O of a curvature radius R of a blend round with respect to a throat width O is maintained at about 0.4. A second section B from the throat 4 upstream to a branch point 7 at a distance substantially equal to a throat length is formed such that the value R/O is consecutively and linearly varied from about 0.4 to about 0.7. In a third section C from the branch point 7 to a front edge 3a of the blade profile, the entire blend round is formed such that the value R/O is maintained at about 0.7. Consequently, it is possible to enhance performance and enlarge the blend round so as to reduce a machining cost.;COPYRIGHT: (C)1997,JPO
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