A new spiral cooling structure located in the U-shaped cooling channel for turbine rotating blades

The cooling of the chord region in modern gas turbine blades is crucial. Many turbulence structures cause excessive resistance in the channel, and the drag reduction structures weaken the heat transfer in the channel too much. To address this issue, an innovative spiral cooling structure for vertical area of U-shaped channel is proposed. This structure is used to replace the complex turbulence structure inside the U-shaped channel. With only a small increase in resistance, it can significantly improve the channel's overall heat transfer uniformity. In this paper, the calculation models of four spiral cooling structures located in the first channel and the second channel respectively are established. Steady state operating condition calculation based on commercial software CFX. Under the typical Reynolds number of 20000, considering the rotation number of 0–0.4, the flow and cooling characteristics of clockwise and counterclockwise spiral cooling structures are analyzed in detail. Through comparative analysis, it is found that the U-shaped channel with spiral cooling structure can achieve an average heat transfer enhancement of 21% and 14.9% in the first channel and the second channel respectively. The channel's comprehensive thermal performance is enhanced by 14.2% and 9% on average. Then, in order to deal with the problem of the decrease of the blade thickness due to the increase of the channel height, the spiral structure is flatted in the height direction. After the same calculation method, it is found that the flatted channel enhances the regional heat transfer by 21%, and the local comprehensive thermal performance of the channel is improved by 9.72% on average.