Parametric modelling and multidisciplinary design optimization of 3-D internally cooled turbine blades

This paper presents the methodology of parametric modelling design and the fully automated integration strategy for the multidisciplinary design optimization of internal cooled turbine blades. Parametric geometric models of three-dimensional cooled turbine blades are developed, the suction surface and pressure surface are presented by a series of quintic splines, the leading edge geometry and the trailing edge geometry are represented by circular arc which helps to maintain a smooth geometrical connection at the end points of the pressure side and the suction side. Wall thickness functions are defined to get the coolant flow passage profile, and feature modelling methods are employed to create the platform and rabbet. The coupled aero-thermal-fluid analysis based on compressible Navier-Stokes equation with k-ε turbulence model is used to solve the flow-field and solid-field. K-S functions methods is used to solve the multi-objective optimization problem. The objective is to minimise the average temperature and the maximum blade temperature, and to minimise the total pressure loss, with the constraints on max stress and frequency. The internal cooling configuration and blade profiles are optimised for higher performance. The blade aerodynamic and cooling performance is improved significantly.