Multiobjective Optimization for Duct and Strut Design of an Annular Exhaust Diffuser

Abstract

This paper describes the aerodynamic optimization of a typical exhaust diffuser for a heavy duty gas turbine. The objective is to maximize diffuser performance and, in this way, pressure recovery by optimizing the geometry for two given inlet conditions. To validate and adjust the numerical set-up, experimental data from measurements on the test model is used. The numerical results obtained by using TRACE compares with the experimental results. An optimization process is applied using the framework AutoOpti developed by DLR, which combines evolutionary strategies with surrogate models in order to select optimal geometric parameters. Finally, the differences between the baseline and several optimized designs are discussed and the impact of different parameters on diffuser performance is demonstrated.