Variable-Fidelity Optimization of Film-Cooling Hole Arrangements Considering Conjugate Heat Transfer

摘要

In spite of its crucial importance,conjugate heat transfer has been ignored in most film-hole-array optimizationstudies due to the burdensome associated with added complexity and computational requirements. To cope with thisissue and to consider the conduction cooling effects,the hierarchical kriging model was applied to optimize the filmcooling hole array on a high-pressure turbine nozzle. The hierarchical kriging model used in this study consists ofthree levels and was constructed effectively using both adiabatic-condition-based analyses and conjugate-heattransfer analyses. The expected-improvement-based efficient global optimization algorithm was coupled with thehierarchical kriging model to improve the efficiency of the whole optimization process. As a result,the requiredcomputation time to obtain the optimum solution was markedly reduced to a quarter compared to the time without thehierarchical kriging model,and the viability of the method for nighly nonlinear and time-consuming problems wasproved. Additionally,the conjugate-heat-transfer-based optimum film-hole array showed that it has improved theoverall cooling effectiveness and could have a different shape compared to the array obtained under the adiabatic wallcondition. The detailed causes of the resultant hole arrangement were thoroughly examined with respect to both theexternal and internal cooling aspects.