Validation of thermodynamic gas turbine models using frequency-domain techniques

Frequency-domain identification techniques are applied to directly estimate linear s-domain models of an aircraft gas turbine, at a range of operating points. These models are used to validate the linearised thermodynamic models derived from the engine physics. The possible sources of error are discussed in turn, these being noise, nonlinearities, the combustion delay and thermal effects. The results indicate that the linearised thermodynamic models do not adequately represent the engine dynamics.