Heat Transfer in Trailing-Edge Channels with Slot Ejection Under High Rotation Numbers
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The regionally averaged heat transfer coefficients were measured in a wedge-shaped channel (D h = 2:22 cm, A c = 7:62 cm 2) to model an internal cooling passage near the trailing edge of a gas turbine blade. This test section was configured so that the inlet coolant exhausts through the slots to simulate the trailing-edge ejection. Therefore, the local mass flow rate decreases along the streamwise direction due to the coolant discharging through the slots. The effects of slot ejection enhance heat transfer near the narrow side while decreasing heat transfer on the wide side of the channel at the stationary condition. The inlet Reynolds number of the coolant varies from 10,000 to 40,000, and the rotational speeds vary from 0 to 500 rpm. The inlet rotation number varies from 0 to 1.0. The local rotation number and buoyancy parameter vary by the different rotational speeds and local Reynolds number in each region. Detailed spanwise and streamwise heat transfer distributions are strongly affected by the slot ejection at both the stationary and rotating conditions. This study shows that the rotation number and buoyancy parameter are useful parameters to correlate the effect of rotation on heat transfer in the current study. 2008 by the American Institute of Aeronautics and Astronautics, Inc.