Thermal-hydraulic study of a wire spacer fuel assembly

Thermal–hydraulic numerical simulation of fuel sub-assembly using a dedicated meshing tool

“…Pointer et al (2009a) extended these studies to 217 fuel pin assemblies in support of initial efforts to benchmark heat transfer predictions using the RANS models against conventional sub-channel models. Rolfo et al (2012) examined the effect of the turbulent Prandtl number. Since the low value of the Peclet number, higher turbulent Prandtl number, as suggested in Cheng and Tak (2006), has also been tested in some configurations (7-pins and 19-pins geometries at Re = 25000), but without noticing a large variation of results (the percentage variation of the Nusselt number for the Dirichlet boundary condition is below 1% and below 3% in the case of a Neumann boundary condition).…”

“…Flow and heat transfer Péniguel et al (2010) 7-271 Flow and heat transfer Kim and Ahmad (2005) 217 Flow and heat transfer Ahmad and Kim (2006) 7-19 Flow and heat transfer Raza and Kim (2008) 7 Wire-spacer shape Chang and Tavoularis (2007) 37 P/Dp < 1.3 Baglietto (2007) 217 P/Dp < 1.3 Pointer et al (2008) 7 LES approach Pointer et al (2009a) 217 RANS approach Rolfo et al (2012) 19…”

Generating Hexahedral Mesh for Wire-wrapped Fuel Assembly With RBF Mesh Deformation Method

“…Due to the geometry complexity of the wire-wrapped fuel assembly, it is hard to mesh the wire-wrapped assembly with high mesh quality (Rolfo et al, 2012). Most of present simulations were performed with meshes consisting of tetrahedron or polyhedron cells.…”

“…The helical surface of the wire is approximated through fine hexahedral cells. Besides these traditional methods, Smith (Smith et al, 2008) and Rolfo (Rolfo et al, 2012) adopted a special technique called the nodematched body-fitted conformal mesh technique. The hexahedral mesh is first generated for the fuel assembly without the helical wire and then the mesh is deformed to account for the position of the wire wrap.…”

A DNS study on the effects of streamwise convex surface curvature on coherent structures in turbulent boundary layers

“…the presence o f the w ire-w rap spacer induces lateral com ponents o f velocity in the assembly thus inducing a net transport o f fluid carrying m om entum and energy from each sub-channel to adjacent sub-channels. (Bishop and Todreas, 1980;Gajapathy et al, 2007;Rolfo et al, 2011). In the central sub channels, while the w ire-w rap on one rod brings flow into a particular sub-channel, the wire-wrap on an adjacent rod convects fluid out o f that sub-channel (for exam ple, see Figure 2.4).…”