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Pin Fin Array Cooling |
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Project Funded by: Pratt & Whitney |
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Researcher: Alan Thrift |
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The desire to achieve higher heat transfer augmentation for turbine blades is fueled by the increased power output and efficiency that is achievable with high turbine inlet temperatures. The use of internal cooling channels fitted with pin fin arrays serves as one method of accomplishing this goal. Consequently, the addition of pin fin arrays comes at the expense of increased pressure drop. Therefore the pin fin geometry must be judiciously chosen to achieve the required heat transfer rate while minimizing the associated pressure drop. |
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This project culminates in the measurement of both pin fin force and array pressure drop as they relate to changes in the array geometry. Specifically, the effects of Reynold’s number, spanwise pin spacing, streamwise pin spacing, pin aspect ratio, and flow incidence angle. Direct two-component force measurement is achieved with a cantilever beam force sensor that uses highly sensitive piezoresistive strain gauges, relating the strain at the base of the beam to the applied force. With proper characterization, forces as small as one-tenth the weight of a paper clip are successfully measured. Additionally, array pressure drop measurements are achieved using static pressure taps. |
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Figure 1. A closed loop test rig was constructed to complete project objectives. |
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Figure 2. Schematic of test rig. |
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Figure 3. Drag measurements are made using an elastic beam sensor while pressure drop measurements are made using static pressure taps. |