An airborne gas turbine engine with its accessories and installation frame constitutes the propulsion system of an airplane. In industrial practice, control system development for airborne gas turbine engines is part of an iterative converging process which involves control design and propulsion system dynamic testing. Competitive pressure to reduce development time and airframer demands for continuous improvements in propulsion performance have created the necessity to develop predictive reliable dynamic models which can simulate complex physical phenomena taking place inside a gas turbine engine. An example of such a dynamic model restricted to the core of an airborne gas turbine engine (gas generator) is presented in this paper. The physics based one-dimensional generic model can be used for propulsion system dynamic analysis tasks such as variable geometry optimization, air bleed extraction optimization, evaluation of component scaling effects, surge and rotating stall frequencies, determination of surge and rotating stall stability boundaries and for model based control design. The notion of surge domain is introduced and model predictions are given. The model can be partitioned to obtain an one-dimensional compressor dynamic model which can simulate onset and development of surge and demonstrate rotating stall boundaries. Simulation results which demonstrate the usefulness of the model are included.

Full Authority Digital Electronic Control of Pratt and Whitney 305 Turbofan Engine

Dynamic Modeling of Airborne Gas Turbine Engines

A f u l l authority d i g i t a l e l ec t ron ic control was selected f o r the Pra t t & Whitney Aircraft PW2037 turbofan transport engine. This control system wi l l provide optimum engine performance and fuel economy, high operational r e l i a b i l i t y , minimum p i l o t workload, simplified control maintenance procedures, and maximum engine protection. A genera l description of the system i s presented and benefits a r e discussed.

Transport engine control design

This paper considers an extension of the tuning regulator design method of [1]-[3] to include a large class of nonlinear multivariable systems. In particular, it is desired to solve the servomechanism problem for an unknown nonlinear plant, which is assumed to be open loop asymptotically stable, for the class of constant set-points and disturbances. In this case, three classes of nonlinear controllers, which are gain-scheduling controllers, are described: (i) error attenuation, (ii) feedforward and (iii) robust controllers, and sufficient conditions by which the resultant closed loop system gives global asymptotic stability and regulation are obtained. The sufficient conditions obtained simplify to the necessary and sufficient conditions [1] associated with the case when the plant is assumed to be described by a linear time-invariant model.

Full Authority Digital Electronic Control of Pratt and Whitney 305 Turbofan Engine

Citations

Dynamic Modeling of Airborne Gas Turbine Engines

References

Transport engine control design

Control of Unknown Nonlinear System using Gain-Scheduling Tuning Regulators

Ensuring surge-free engine operation on today's turbofan powered business jets

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Full Authority Digital Electronic Control Turbofan Engine Demonstration