Simulation of fluid -structure interaction in turbomachines

Flow induced vibration in turbomachine blade rows is a coupled fluid-structure problem. Thus, instead of utilizing separate fluid and structural models, a coupled interacting fluid-structures analysis is needed. This research addresses this need by application of the new finite element code TAM-ALE3D that solves the three-dimensional unsteady Euler equations in a multi-stage turbomachine environment. The TAM-ALE3D code is derived from the ALE3D code of Lawrence Livermore National Laboratories, and includes algorithms required to model turbomachine geometry. Added features include partially non-reflecting inflow/outflow boundary conditions, and parallel algorithms that allow multiple blade rows to be modeled simultaneously on parallel computer architectures. TAM-ALE3D predictions of the rotor-generated upstream-traveling potential field within the inlet guide vane (IGV) row of the Purdue Transonic Compressor Facility compare well to experimental data. Fluid-structure interaction is first demonstrated by modeling both the isolated rotor flow field and rotor blade, with the aerodynamic damping on the blades quantified through a simulated impact hammer test. Fluid-structure interaction is further demonstrated in a multi-stage environment by simultaneous modeling of the IGV material and flow field, yielding the stresses within the IGV due to excitation from the downstream rotor potential field. The results show the TAMALE3D model not only captures important aerodynamic phenomena within multi-stage turbomachines, but also captures full fluid-structure interaction effects and predicts internal blading stresses