Heat transfer in a rotating lateral outflow trapezoidal channel with pin fins under high rotation numbers and Reynolds numbers

Abstract

Existing heat transfer research on wedge-shaped channels with pin fins at the trailing edge has mainly focused on Reynolds numbers below 40,000. Larger inlet parameters are rarely considered, resulting in uncertainties in this aspect. Therefore, in this study, the heat transfer characteristics in a rotating lateral outflow trapezoidal channel with pin fins, which is a typical model of the internal cooling passage in a turbine blade, were experimentally investigated under the Reynolds number range of 10,000–110,000, rotation number range of 0–0.5, and speed range of 0–1000 rpm. The differences in the heat transfer at different entry conditions were compared. For the non-rotating condition, the heat transfer at a high Reynolds number (110,000) was four to nine times that at a low Reynolds number (10,000). For the rotating conditions, when the dimensionless parameter X/D (coordinate in radial direction/channel hydraulic diameter) was greater than seven for the inner surface and equal to eight for the outer surface, the heat transfer on the leading surface exceeded that of the trailing surface. Moreover, the critical rotation number, which varied with X/D, was noted on the leading surface. Finally, the heat transfer under a high Reynolds number and high speed were investigated. The findings under a high Reynolds number were similar to those under a low Reynolds number. The research of this paper supplements the heat transfer of wedge-shaped pin fins channel at the trailing edge of turbine blade under the condition of high Reynolds number and rotation number.