Thrust and Flow Prediction in Gas Turbine Engine Indoor Sea-Level Test Cell Facilities

摘要

The principal aim of this research was to provide a detailed understanding of theperformance of gas turbine engines inside indoor sea-level test beds. In particular theevaluation of both thrust correction factors and the estimation of the mass flowentering the test cell were at the core of the research.The project has been fully sponsored by Rolls-Royce pIc. Initially, their principalobjective was to assess the relevance and accuracy of CFD when applied to thrustmeasurement inside indoor test beds with an intended outcome of minimising the useof expensive experimental measurements.The different system interfaces and accounting systems for in-flight conditions,available in the open literature have been developed and adapted for indoorenvironments. This has led to the definition of three different thrust correctionequations using alternative definitions of thrust correction factor. Aero-dynamicprinciples have been applied for the derivation of one-dimensional relationships forthe calculation of each thrust correction factor using generic engine-cell performanceand dimensions.A one-dimensional analytical model has been developed to represent the enginedetunerejector pump. This is able to characterise the engine-cell system performanceand is used as the main tool for providing a matching procedure capable of predictingthe cell entrainment ratio.By processing experimental data relevant to different engine-cell configurationsthrough the ejector pump analytical model, a method for achieving the entrainmentratio control inside the cell has been identified.The CFD work has been concentrated into three main activities:• A quantitative extrapolation of the thrust correction factors including, thepre-entry force, the external and the total bellmouth force, the throat streamforce, the intake momentum drag and the base drag.• The representation of the engine-detuner ejector performance for avariety of engine-cell configurations.• The modelling of the generic test cell components including the inletstack, the cascade elbow, the exhaust stack & the blast basket.The outcomes of this research have been very successful in enhancing the validity ofthe thrust correction equations developed .. In particular, the use of a one-dimensionalapproach in their estimation has been shown to be fully justified. The work has alsoemphasised the value of CFD in supporting the derivation of the matching procedurefor predicting and controlling cell entrainment ratio. Indeed, one of the strongestoutcomes of this work has been the conclusion that both the engine-cell characteristiclines computed with the one-dimensional model and those computed with CFD fordifferent cell configurations are almost identical.In addition, the use of CFD as a tool for the quantitative evaluation of the thrustcorrection factors has been established. Finally, the CFD results have facilitated anenhanced understanding of the complex flow structure inside indoor test cells