ENGINE PERFORMANCE PREDICTION FOR VARIED LPT VANE GEOMETRY UTILIZING TEST RIG DATA AND COMBINED CFD AND CYCLE MODELS

摘要

Engine performance is a result of the interaction between individual components. Any deviation from the design geometry does not only affect the flow locally, but can also lead to significantly altered whole engine performance. Specifically for Low Pressure Turbine (LPT) vanes, erosion and subsequent refurbishment can lead to considerable changes in geometry. Following vane refurbishment, the part's effective flow area may be measured and adjusted to meet turbine nozzle matching requirements for the engine build. Other parameters such as pressure loss and outlet flow angle are not evaluated, but rather assumed equivalent to a new part. Consequently, a large portion of vanes is rejected only after engine test, making it an expensive process. A new methodology is presented here that promises to reduce the cost of acceptance tests by predicting the performance of an engine with a refurbished vane. It follows a multi-fidelity approach involving experimental testing, zero-dimensional cycle modeling and three-dimensional Computational Fluid Dynamics (CFD). Baseline performance maps of the LPT stage with varied vane geometries are generated using CFD. The obtained performance maps are incorporated into an engine cycle model. A multiple map feature for the cycle model was developed for this purpose. It enables accessing a plurality of stored maps representing a single LPT. Using performance parameters derived from test data of the isolated vane, a performance map is generated through interpolation of the baseline maps. The expected engine performance can now be readily predicted, and a well-founded decision on acceptance of the refurbished vane made.