Abstract
This paper presents an experimental study and numerical simulation of the unsteady flow mechanisms in a single stage axial flow turbine which is simulated the LP turbine airfoils. The target of this study is to verify the influence of the purge flow from the Rim-seal cavity on the flow field in the rotor passage, which leads to changes of the secondary flow behavior especially in the rotor hub region. To observe the unsteady flow pattern at rotor downstream, detailed 3-D unsteady measurements using a slant-type hot wire probe is performed. The result of unsteady measurement observed the secondary flow and the leakage flow in the tip region without the purge flow as well as the steady flow measurement with 5-hole probe. A three-dimensional, time-dependent numerical simulation shows the unsteady flow interactions between the main flow and purge flow.
