High Fidelity Simulation of Fluid-Structure Interaction in a 1½ Stage Axial Turbine

Abstract

A high fidelity, fully coupled numerical technique for the simulation of airfoil and turbomachinery aeroelasticity configurations is presented. The unsteady structural and fluid dynamics equations are discretized by a control volume technique which is second order accurate in space along with a dual time-step scheme that is second order accurate in time. The momentum conservation equation for the solid is written in terms of the Piola-Kirchoff stresses and the displacement velocity components. The stress tensor is related to the Lagrangian strain and displacement tensors using the St. Venant-Kirchoff constitutive relationship. Source terms at the surface of the solid are included to account for surface pressure and body forces. Previous fluid-structure interaction studies of Turek’s cylinder flag and the AGARD 445.6 airfoil have provided confidence needed to accurately perform fluid structure interaction simulations in turbomachinery. In this study, a 1½ stage axial transonic turbine is simulated and results are validated with experimental data. Simulation results indicate that the inclusion of airfoil vibration leads to improved agreement with experimental unsteady surface pressures compared to simulations with fixed airfoils.