Heat Transfer in Trailing Edge, Wedge-Shaped Cooling Channels under High Rotation Numbers

摘要

Heat transfer coefficients are experimentally measured in a rotating cooling channel used to model an internal cooling passage near the trailing edge of a gas turbine blade. The regionally averaged heat transfer coefficients are measured in a wedge-shaped cooling channel (D_h =2.22cm, A_c=7.62cm~2). The Reynolds number of the coolant varies from 10,000 to 40,000. By varying the rotational speed of the channel, the rotation number and buoyancy parameter range from 0-1.0 and 0 - 3.5, respectively. Significant variation of the heat transfer coefficients in both the spanwise and streamwise directions is apparent. Spanwise variation is the results of the wedge-shaped design, and streamwise variation is the result of the sharp entrance into the channel and the 180° at the outlet of the channel. With the channel rotating at 135° with respect to the direction of rotation, the heat transfer coefficients are enhanced on every surface of the channel. Both the non-dimensional rotation number and buoyancy parameter have proven to be excellent parameters to quantify the effect of rotation over the extended ranges achieved in this study.