In this study, an aerostruetural analysis using a proper orthogonal decomposition vrith a neural network is proposed for accurate and efficient aerostructural wing design optimization using tbe reduced-order model. Because reducedorder-model basis weighting estimation bas a limitation in that its robustness cannot be guaranteed by various design variables and wing deformation due to fluid structure interaction, this study employs tbe neural network, which is capable of perceiving tbe relationship between tbe input variables and reduced variables for the proper orthogonal decomposition to complement tbe defects. To construct tbe proper orthogonal decomposition with a neural network, tbe neural network is learned using pairs of design variables and reduced variables from snapsbot data obtained from tbe aerostructural analysis. Because the proposed aerostructural analysis using a proper orthogonal decomposition with a neural network is applied to validation cases and its results are compared to those of the full-order analysis, it is investigated that tbe proposed analysis algorithm has tbe capability to accurately and efficiently predict tbe aerodynamic and structural performances of wings that are considered about wing deformation. Furthermore, because tbe design optimization problem minimizing tiie weigbt of a wing design is performed with tbe analysis algorithm, it is confirmed that it can be a more efficient design than a conventional design method using a second-order polynomial model, wbicb consists of a greater number of experiment designs than the number of snapshots.'^spnng L/D Nomenclature = weights in a neural network model = spatial correlation matrix = force generated to springs = vector of the hidden nodes = actual snapshot = spring stiffness coefficient = lift-to-drag ratio

This paper presents the application of airfoil impeller for enhancement of aerodynamic performance of a high speed centrifugal fan. Three airfoil impellers are proposed, considering the maximum thickness and the location of maximum thickness of the airfoil. C4 airfoil thickness distribution is applied to the three airfoil impellers. The impellers are evaluated using CFD (computational fluid dynamics) and suction power test. From the results, it is confirmed that flow separations on the pressure side of the impeller blades and the pressure side of diffuser blades are reduced when airfoil blade is applied to the impellers. It is also confirmed that with the centrifugal fan having airfoil impellers, there is an increase in fan efficiency by approximately 3% and reduction in specific sound level by approximately 1.3 dB(A).