Heat Transfer in Leading Edge, Triangular Shaped Cooling Channels With Angled Ribs Under High Rotation Numbers

Abstract

The gas turbine blade/vane internal cooling is achieved by circulating compressed air through the cooling channels inside the turbine blade. Cooling channel geometries vary to fit the blade profile. This paper experimentally investigated the rotational effects on heat transfer in an equilateral triangular channel (Dh=1.83 cm). The triangular shaped channel is applicable to the leading edge of the gas turbine blade. Angled 45 deg ribs are placed on the leading and trailing surfaces of the test section to enhance heat transfer. The rib pitch-to-rib height ratio (P/e) is 8 and the rib height-to-channel hydraulic diameter ratio (e/Dh) is 0.087. Effect of the angled ribs under high rotation numbers and buoyancy parameters is also presented. Results show that due to the radially outward flow, heat transfer is enhanced with rotation on the trailing surface. By varying the Reynolds numbers (10,000–40,000) and the rotational speeds (0–400 rpm), the rotation number and buoyancy parameter reached in this study are 0–0.58 and 0–1.9, respectively. The higher rotation number and buoyancy parameter correlate very well and can be used to predict the rotational heat transfer in the equilateral triangular channel.