Production and Development of Secondary Flows and Losses Within Two Types of Straight Turbine Cascades: Part 2 — A Rotor Case
Part 1 of this paper[1] presented the detailed mechanism of secondary flows and the associated losses occurring within a straight stator cascade with a relatively low turning angle of about 65°. Significant contribution of secondary flows on the loss production process was shown only near the blade suction surface downstream from the cascade throat (Z/Cax=0.74) in which region flows decelerated due to adverse pressure gradient. In the second part, the same experimental analysis was applied to a straight rotor cascade with a much larger turning-angle of 102°. Flow surveys were made at twelve traverse planes located throughout the rotor cascade. The larger turning results in a similar but much stronger contribution of the secondary flows on the loss developing mechanism. Evolution of overall loss starts quite early within the cascade, and the rate of the loss growth is much larger in the rotor case than in the stator case.