A new method of predicting gas turbine off-design performance is presented. This method, referred to as the core control method, is based on the idea that performance across a gas turbine depends on a single parameter that controls the energy input to the said gas turbine. It is shown that only the design-point performance of a gas turbine is needed to predict its off-design performance, and that neither compressor nor turbine characteristics are required.;The core control method is then used to predict the off-design performance of a Rolls-Royce Viper Mark 521 as a proof-of-concept, after which, the new and deteriorated off-design performance of three Rolls-Royce RB211-24GT gas turbines is predicted.;In addition to the discussions on the involved theories and the performance predictions, the process by which the deteriorated RB211-24GT performance data was analyzed, and the sources and propagation of measurement uncertainties are also discussed.;A thermodynamic model is developed for predicting the off-design performance of a single-spool turbojet and a two-spool gas generator with a free power turbine. This model is further developed to simulate the effects of handling bleed schedules, performance limiters and performance deterioration. |