A Parallel Algorithm for Simulation of Unsteady Flows in Multistage Turbomachinery

Abstract

The numerical simulation of unsteady flow in multi-stage turbomachinery is computationally expensive. A parallel code using message-passing interface libraries, which was developed to reduce the turnaround time and the cost of computation, is presented in this paper. The paper describes the details of the parallel algorithm, including the parallelization rationale, domain decomposition and processor allocation, and communication patterns. The numerical algorithm was used to simulate the unsteady flow in a six-row test turbine. The numerical results present the salient features of the turbine flow, such as the temporal and spatial vari1 2 ation of velocity, pressure, temperature and blade force. To illustrate the advantages of parallel processing, the turnaround time of the turbine flow simulation was compared on several computers where the code was run in parallel and sequential mode. Nomenclature Cp Pressure coefficient F Force f Frequency p Pressure r Radius T Temperature γ Ratio of specific heats of a gas μ Viscosity ρ Density τ Skin friction ω Angular velocity Subscripts F Half-amplitude Fourier transform hub Hub location n− d Non-dimensional tip Tip location −∞ Upstream infinity Superscripts ∗ Total (or stagnation)