Two- and three-dimensional CFD-simulation of flow-induced vibration excitation in tube bundles

Two- and three-dimensional simulation models for the computation of flow-in duced vibration of tube bundles subjected to single-phase cross-flow are ap plied for a full flexible tube row and a tube bundle. The flow-induced vibr ation is simulated with the CFD (Computational Fluid Dynamics) program STAR -CD in combination with a coupled solver for the differential equations of parallel vibrating tubes for two- and three-dimensional calculations. Addit ionally a coupled FEM (Finite Element Method) program is used for the three -dimensional simulation of different tube support conditions. The CFD progr am solves the Navier-Stokes equations with different k epsilon-models or an implemented kw-model for the unsteady turbulent viscous and incompressible flow field. The object of this project is to find a model, which describes the fluidelastic vibration excitation and enables an accurate computation of critical velocities in tube bundles comparable to those determined with the new design recommendation by K. Schroder and H. Gelbe, New design recom mendations for fluidelastic instability in heat exchanger tube bundles, ASM E AD-Vol. 53-2, Fluid-Structure Interaction, Aeroelasticity, Flow-Induced V ibration and Noise, 1997, Volume II, pp. 211-219 (s. a. Journal of Fluids a nd Structures, 13 (1999), to be published). Then it will be possible to inv estigate independently the influence of the structure data and the fluid pr operties on the onset of instability. The presented model is validated with experimental data and compared with existing models in the literature. Dif ferent grid discretizations of the flow field and turbulence models were te sted for rigid and flexible tubes and the simulation results for the fluid forces, the pressure distributions and the onset of instability are compare d with experimental data for a tube, a tube row and a tube bundle subjected to cross flow. (C) 1999 Elsevier Science S.A. All rights reserved.