Transient Expansion of the Components of an Air Seal on a Gas Turbine Disc

Using simple finite-difference models with appropriate boundary conditions, methods have been developed for predicting the movements of the critical components of an air seal on the face of the first High Pressure Turbine Disc of a typical two-spool Gas Turbine. The methods have been applied to two testing transients - the acceleration and the deceleration between the Ground Idling and Maximum Speeds. In the acceleration, seal openings of double the equilibrium value are predicted to persist for 30 s after completion of the speed transient.