Backflow Phenomena Caused at Off Design Flow Rate in Rotating Flow Passage of Axial Flow Turbomachinery: Part 2. Upstream Backflow

摘要

It is not possible to say that upstream backflow, which appears near the casing wall at the leading edge of impeller inlet, is induced in the rotating flow passage due to the effect of expanded downstream backflow, which was induced near hub wall at the trailing edge of impeller discharge at a high flow rate before the occurrence of upstream backflow and the expansion of flow region with the decrease in flow rate. Upstream backflow is induced basically due to the separation of fluid particles from the blade surfaces at the leading edge of impeller inlet.