The Feasibility of Multidimensional CFD Applied to Calandria System in the Moderator of CANDU-6 PHWR Using Commercial and Open-Source Codes

Abstract

The moderator system of CANDU, a prototype of PHWR (pressurized heavy-water reactor), has been modeled in multidimension for the computation based on CFD (computational fluid dynamics) technique. Three CFD codes are tested in modeled hydrothermal systems of heavy-water reactors. Commercial codes, COMSOL Multiphysics and ANSYS-CFX with OpenFOAM, an open-source code, are introduced for the various simplified and practical problems. All the implemented computational codes are tested for a benchmark problem of STERN laboratory experiment with a precise modeling of tubes, compared with each other as well as the measured data and a porous model based on the experimental correlation of pressure drop. Also the effect of turbulence model is discussed for these low Reynolds number flows. As a result, they are shown to be successful for the analysis of three-dimensional numerical models related to the calandria system of CANDU reactors.

Unsteady Simulation of a Full-Scale CANDU-6 Moderator with OpenFOAM

“…The numerical method is verified and validated in the previous research by the authors [14,16]. The pressure drop with comparison of STERN laboratory experiment shows an error within 16.3% from the experimental data [16] (see Figure 4). The pressure drop is measured for isolated four-row bank of aligned cylinders of 33.02 mm diameter and 71.4 mm spacing.…”

“…In this study, Open Field Operation and Manipulation (OpenFOAM) [15], an open-source CFD solver, is used to simulate the three-dimensional flows improving the computational efficiency by parallel computing which does need no proprietary license. The feasibility on the computation of 3-D flow has been tested and validated by the comparison with other codes by the authors [16], but the models are just focused on the pressure drop in a straight channel. In this paper, the full capacity of OpenFOAM CFD is tested for a turbulent unsteady flow as observed in the 1/4 scale of test [8] to resolve the 3-D structure of circulation flow in the moderator system of a real-scale CANDU-6 reactor.…”

“…We have studied the suitable grid levels and the validation of pressure drops with the comparison with various commercial codes such as ANSYS-CFX and COMSOL (COMputer SOLution) Multiphysics as well as experimental data using OpenFOAM [16]. However, the full simulation of CANDU- 6 is not yet attempted because of its high complexity in three dimensions.…”

Low Reynolds Number Flow around Transversely Arranged Elliptic Cylinders in a Channel of Slit Nozzle

“…Flow properties are weight-averaged for the mixture ratio of raw materials: density and viscosity are easily calculated just from the linear combinations [8]. The "Laminar Fluid Flow" module in COMSOL Multiphysics 5.2 is used for the numerical computation where FGMRES linearization and Petrov-Galerkin artificial viscosity are applied, based on finite element method (FEM) [9]. Fig.…”

“…The simple Blasius profile is used in order to calculate their boundary-layer thickness [7]. By just cutting them, the RMS (root mean square) errors flow distributions from the mean values are computed as a lumped parameter for indicating flow uniformity [9]. The RMS error is plotted and compare with each other in Fig.…”