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Film-Cooling of Chamber Walls |
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The current demands for high performance gas turbine engines can be reached by raising combustion temperatures to increase power output. Predicting the performance of a combustor is quite challenging, particularly with respect to the complex flow and thermal fields produced by the introduction of high momentum dilution jets into the chamber. To better understand the complex physics in a combustor, it important to measure the flow and thermal fields resulting as the jets are injected into the chamber and interact with the mainstream crossflow. |
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Cooling along the chamber walls of a combustor is needed to protect the surfaces from the high gas temperatures. Typically film-cooling is used whereby coolant is injected through the combustor walls. Predicting the performance of this coolant injection when interacting with the higher momentum, larger dilution jets is difficult. Several different experimental techniques are being used to understand the film-cooling / dilution jet interactions that include infrared thermography, thermocouple probes, and laser Doppler velocimetry. Cooling effectiveness contours, shown in Figure 2, allow us to analyze the surface temperatures to identify hot regions with no cooling that will be problematic in the engine. Figure 3 shows the flow field of a dilution jet interacting with the crossflow as measured using a laser Doppler. velocimeter. |
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Figure 1. Typical aero-engine combustor. |
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Figure 2. Cooling effectiveness on a combustor liner. |
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Figure 3. Measured dilution jets interacting with a cross-flow. |
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Project Funded by: Pratt & Whitney |
