A two-dimensional finite element method large eddy simulation for application to turbulent steam generator flow

A major concern in the nuclear power industry is failure of the steam generator tubes. Failure of the tubes necessitates the plugging of the failed tubes with the result that nuclear plants are forced to operate at lower, or derated, power levels after expensive repairs. Turbulence-induced vibration is a primary cause of premature and accelerated fretting and wear of the steam generator tubes. An alternative unsteady analysis method for incompressible fluid flow problems is demonstrated. The approach employs large eddy simulation (LES) in conjunction with the finite element method (FEM). A segregated solution technique, solving for each field variable at all nodes, diminishes storage requirements by eliminating the need to solve the globally assembled finite element matrix. A direct benefit is that finer nodalizations can be employed. Equal-order quadrilateral elements are used to facilitate the segregated solution algorithm. The solution scheme is accurate to higher order to mitigate the effects of numerical diffusion in the advection terms. The Smagorinsky-type closure model for the sub-grid scale turbulence is used. The model is easily implemented into this algorithm. This combination of FEM and LES is unique. The time-dependent terms are explicitly treated. The time history of a steam generator tube bundle experiment is studied. The results show the applicability of FEM/LES and determine the prospects for further development of this methodology