Fast Reactors and Accelerator Driven Systems Knowledge Base

Conference Article: Calculation of fluid flow and heat transfer in a rod bundle with geometrical disturbance based on the 'locally exact' finite-difference scheme

Abstract

The results of numerical simulation of fluid flow and heat transfer in the rod bundle with geometrical disturbance are presented. The geometry of the rod bundle was chosen according to the benchmark problem for 9th IAHR Working Group Meeting (April 7-9, 1998, Grenoble, France). For such a case, experimental data for local velocity and wall shear stress distributions were obtained by group of F. Mantlic at NRI (Czech Republic). Another series of the experiments, which provide a data on the wall temperature profiles had been done at the IPPE (Russia). Both experiments provide complete set of data for comparison with the results of numerical simulation. Reynolds equation for axial velocity component has been simulated in two dimensions. Turbulent shear stresses have been simulated by turbulent eddy viscosity with anisotropy defined for radial and azimuth components. Secondary flows have not been taken into consideration. The averaged energy conservation equation closed with anisotropic turbulent conductivity coefficients was simulated. Reynolds and energy conservation equations have been discretizated by the Efficient Finite-Difference (EFD) scheme based on the “locally exact” analytical solution. The comparison of the accuracy of the EFD method and traditional central-difference scheme has been performed. The benchmark problem has been simulated using components of the Computational Object-Oriented Library for Fluid Dynamics (COOLFD) which is a new-generation programming tool aimed to improve the development of the CFD application for complex calculation areas such as rod bundle of nuclear reactor. Comparison of calculated results and experimental data is presented for the local shear stress, axial velocity and the wall temperature distributions in the “geometrically disturbed” region around dislocated rod

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Reference:

Technical committee meeting on methods and codes for calculations of thermohydraulic parameters for fuel, absorber pins and assemblies of LMFR's with traditional and burner cores. Obninsk (Russian Federation) 27-31 Jul 1998

International Atomic Energy Agency, Vienna (Austria)

IAEA-TECDOC--1157, pp:175-183