Non-Deterministic Thermo-Fluid Analysis of a Compressor Rotor-Stator Cavity

Aero engines are subjected to a number of competing requirements. Small variations in geometry or operating conditions can deteriorate blade tip clearance which directly influence engine performance, efficiency and life. Significant effort has been invested in modelling the propagation of input uncertainties in CFD simulations using stochastic meth-ods. In this paper we focus on uncertainty propagation in gas turbine cavity using a Non-Intrusive Polynomial Chaos method. This is an inexpensive method based on the spectral representation of the uncertainty parameters. The polynomial coefficients are evaluated using Probabilistic Collocation method providing an exponential convergence for arbitrary probability distributions. This method has been applied to a rotor-stator cavity at the front of an IP compressor for a large bypass turbofan aero engine. The application is presented for a number of operating parameters as the uncertainty sources and tested for two different input probability distributions. The calculations are carried through from the CFD to the thermo-mechanical modelling to obtain non-deterministic component temperatures and blade tip clearances. I