Design optimization of axial flow compressor blades with three-dimensional Navier-Stokes solver

초록

Numerical optimization techniques combined with a three-dimensional thin-layer Navier-Stokes solver are presented to find an optimum shape of a stator blade in an axial compressor through calculations of single stage rotor-stator flow. Governing differential equations are discretized using an explicit finite difference method and solved by a multi-stage Runge-Kutta scheme. Baldwin-Lomax model is chosen to describe turbulence. A spatially-varying time-step and an implicit residual smoothing are used to accelerate convergence. A steady mixing approach is used to pass information between stator and rotor blades. For the numerical optimization, searching direction is found by the steepest decent method and the conjugate direction method, and golden section method is used to determine optimum moving distance along the searching direction. The object of present optimization is to maximize the efficiency. Optimum stacking line is found to design a custom-tailored 3-dimensional blade for maximum efficiency with other parameters fixed.