Robust optimization of the NASA C3X gas turbine vane under uncertain operational conditions

Abstract

The aim of the current paper is the robust optimization of an internally cooled gas turbine vane by increasing the cooling performance and decreasing the sensitivity of the performance against operational uncertainties. The basic geometry of the C3X vane cooling system consists of ten circular channels for reducing the heat load. The numerical analysis is performed using the conjugate heat transfer methodology and the v2−f turbulence model to minimize the simulation error. The operational conditions are considered to be uncertain with Beta probability distribution functions. For quantification of the uncertainties, the polynomial chaos method is used. The main objective of the present study is to increase the blade life span through the minimization of the vane maximum temperature and maximum temperature gradient. To this end, both deterministic and robust optimizations are carried out via a hybrid evolutionary algorithm. The deterministic optimum blade yields lower maximum temperature and temperature gradients. The optimization results clearly show that the robust optimum design is less sensitive to the operational uncertainties, and the maximum blade temperature and temperature gradient are still remarkably lower than the corresponding values of the baseline C3X vane configuration.