Effect of Rotation on 45-Degree Broken V-Ribs in a 2 Pass Square Channel

The demand for elevated turbine inlet temperatures in gas turbine airfoils requires the innovation of advanced internal cooling designs to enhance turbine durability and performance. The internal cooling passages in gas turbine blades typically feature ribs that are designed to induce turbulent mixing consequently increasing heat transfer. As the turbine blades rotate, the Coriolis and Buoyancy forces affect the fluid flowing through these channels, thereby causing a non-uniformity in heat transfer distribution between the pressure side and suction side of the turbine blade internal cooling channels. Prior studies have explored various geometries of ribs under stationary and rotating conditions. The present study investigates the heat transfer characteristics of a two-pass channel (AR = 1) featuring 60 degree broken-V ribs which has not been studied in detail under rotation. The rib-height to hydraulic diameter ratio is 0.125 and rib-pitch to height ratio of 16. The heat transfer coefficient was measured using transient liquid crystal thermography technique and detailed Nusselt numbers have been reported. The experiments were carried out for varying Reynolds number (35000, 45000 & 60000) to cover a typical range of operating conditions found in air-breathing engines.