An Experimental Study on Unsteady Flow Behaviors in an Axial-Flow Turbine

Using a high-response pressure sensor and a single-slanted hot-wire sensor, the upstream and the downstream flows of an annular turbine rotor were surveyed in detail. The data were time-split to produce animated movies, and the unsteady rotorstator interaction and the associated secondary flow behaviors in the rotor passage were analyzed. The loss decreases when the free stream part of the stator cascade is going to enter the downstream cascade passage and thus the flow will pass the rotor cascade smoothly. On the other hand, the loss increases when the stator wake will dominate the downstream rotor cascade passage.