Experimental Study on Rotational Heat Transfer in Rib-pin Composite Trapezoidal Channels with Varied Rib Configurations

The current work conducts an experimental investigation of the heat transfer performance in a rib-pin composite trapezoidal channel. The channel employs ribs and pin-fins as turbulators, with the ribs arranged in two distinct configurations: forward-swept and backward-swept. The inlet Reynolds number (Re) and rotation number (Ro) respectively vary between 8000 and 24000 and from 0 to 0.83. The results indicate that under static conditions, forward-swept ribs enhance local heat transfer, but they provide no improvement in overall heat transfer within the low-radius region. Under rotating conditions, the heat transfer disparity between the leading and trailing walls progressively diminishes with increasing radius. When using backward-swept ribs, buoyancy forces influence the size of separation vortices induced by the ribs, which in turn reduces the overall heat transfer efficiency under rotation, especially when Ro > 0.5. This study demonstrates that in the trailing edge channel of turbine blades with lateral slots, within the commonly employed range of rotation numbers (Ro = 0 ~ 0.5), backward-swept ribs are more effective when combined with pin-fins, enabling optimal heat transfer performance.