Development of an unsteady parallel approach for three-dimensional stator-rotor interaction

Abstract

An unstructured time-accurate simulation is proposed and discussed for the inviscid stator-rotor interaction of a three-dimensional turbine stage. The solver, based on an upwind total variation diminishing finite volume scheme, is briefly described. To allow a time-accurate simulation for the unsteady flow behaviour, two possible approaches are considered. The first proposal consists of a classical explicit multistep Runge-Kutta scheme. The second approach is based on a dual time-stepping strategy, which exploits the implicit time-marching Newton-Krylov method for the inner iteration. In this case the linear solver of the implicit method is the generalized minimal residual method with right preconditioning obtained by an ILU(0) incomplete factorization. The multiblock parallel version of the solver developed for stage investigations is applied to the turbine annular stage of the VKI Institute, developed and tested under the framework of the BRITE EURAM III Project TATEF. Particular concern is devoted to the development of the numerical strategy and validation of the new approach. Memory and central processing unit time costs are both addressed to verify the performances of the numerical schemes proposed.