Many cooling methods have been developed for gas turbine rotational components. Film cooling is one of the most commonly used technique, which introduces cold air through film cooling holes onto the outer surfaces of gas turbine components to protect them from hot mainstreams. Although film cooling is very effective, it is well known that film cooling could reduce the engine power rating and introduce losses, mainly due to the direct coolant/mainstream interactions. In this paper, a preliminary study of a new closed-loop rotor cooling technique is reported. Filled with suitable heat transfer fluid, this closed loop design is applicable to turbomachinery rotors. Due to the combined buoyancy-centrifugal forces under turbine working conditions, the heat transfer fluid could transport the heat effectively from the outer surface of the blade to the internal cooling air. Instead of relying on the temperature gradient inside the blade walls for heat absorption from the high temperature mainstream side to the low temperature cooling airside, these closed loops act as heat transport superhighways. With proper insulation, the center part of the blade walls could be kept at a lower temperature, comparing to the conventional cooling designs. This would potentially provide vital important extra mechanical strength to the highly loaded turbine blades. Preliminary experimental work and CFD predictions have been conducted to prove this novel design. The tests were conducted using a rotational disk at a speed up to 1500 rpm. A liquid crystal based imaging system was employed to measure the surface temperature under transient conditions. Steady/unsteady 2D/3D CFD predictions were carried out to provide detailed information about the flow and temperature fields inside the proposed cooling configuration. Both experimental and computational work proved that this new design would work, providing the mechanical and manufacturing requirements could be met.

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