Ensemble Learning Based Surrogate Modeling for Gas Turbine Blisk Temperature Predictions

Abstract

Temperature prediction in complex systems like gas turbines provides insights to temperature dependent damage accumulation but usually involves a huge computational cost. For simulation-based prognostics, the computational cost is a major hindrance to a real time implementation. In this work an ensemble learning based multistage surrogate modeling approach is investigated as a possible solution for reducing the computational cost. First the nodal temperature of a turbine blisk is predicted using computational fluid dynamic (CFD) simulations for a limited number of engine operating points. Next the proposed ensemble learning based surrogate modeling approach is implemented to train surrogate models for every node defining the blisk. To achieve computational efficiency, the proposed surrogate modeling framework implements in sequence, clustering techniques for data analysis, multistage polynomial regression modeling, and ensemble learning based model combination. Finally the prediction errors are quantified using the leave-one-out cross-validation method. The result suggests that the computational time could be significantly reduced using the proposed ensemble learning based multistage surrogate modeling technique. The threshold value used to tune the polynomial regression model complexity is also shown to influence the time for surrogate model training.