Gas Turbine Rotor Bow – Experimental Surface Measurement

Tyler Mulholland

Abstract


This report discusses the study undertaken to provide improvements to an experimental apparatus and procedure under continued development to accurately validate numerical studies regarding the thermal bow of a gas turbine compressor shaft. Validation through experimentation will support current research that attempts to understand the influence and significance thermal bow can have on the tendency of an engine to experience the Newkirk Effect. To obtain experimental rotor bow data the procedure and apparatus have undergone an iterative process towards that which allows for the accuracy of the data to be initially quantified. A clear understanding of the areas of uncertainty present in the data allowed for direct methods of improvement to be trialed and implemented. The experimental results of the current iteration have shown positive progress towards repeatability; however, continued improvement is required in the areas identified to validate the numerical predictions. The integrated flexibility introduced as a result of the developed experimental apparatus, procedure and postprocessing techniques have led to a significant increase in the available scope regarding the testing that can now be performed experimentally. The procedural mitigation mechanism of dry cranking is one such avenue of testing that has revealed validity in the experimental approach given the likely trends seen in the relatively small data pool that has been developed so far.

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