Heat transfer enhancement in cooling channels

What is it about?

This article investigates turbulent flow and heat transfer in a fast spinning two-pass channel. The channel represents the small cooling channels drilled inside gas turbine blades to assist with the heat removal from the hot surfaces of the blade. The channel under study has a square cross section with the size of 50.8 mm, and the first and second leg lengths of 514 mm and 460 mm, respectively. The air flow rate and the rotation speed of the shaft are such that the Reynolds number of up to 34,000 and Rotation numbers of up to 0.75 are analyzed. Several computational fluid dynamics (CFD) simulations are conducted for this study, although an experimental test setup is designed and fabricated for future investigations. In the experimental setup, the bottom surface of the channel is provided with adjustable electrical heaters, while the other sides of the channel are well insulated. A total of 12 wireless thermocouples is deployed to measure the temperature of air along the channel. The computational results indicate that higher rotation numbers can result in better mixing of the air in the channel, which yields more uniform temperature distribution and higher heat transfer rates.

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