A stepwise development and validation of a RANS based CFD modelling approach for the hydraulic and thermal-hydraulic analyses of liquid metal flow in a fuel assembly

A quantification method for numerical dissipation in quasi-DNS and under-resolved DNS, and effects of numerical dissipation in quasi-DNS and under-resolved DNS of turbulent channel flows

“…Since quite a number of nuclear applications include wall-bounded turbulent flows, for example, the flow of primary coolant in nuclear fuel rod-bundles (see e.g. [4,5,10,9,11,22,37,39,32]), the fully-developed turbulent channel flow case forms a relevant basic case for the analysis of LES. The authors realise that trends in industrial LES of turbulent channel flows may be obtained from the existing literature.…”

Thermal hydraulic considerations of nuclear reactor systems: Past, present and future challenges

“…On the use of CFD codes for sub-channel analysis, CFD simulations have been performed for PWR fuel assemblies to estimate the single-phase velocity and temperature fields (Ninokata and Merzari, 2007), secondary flow in rod bundles (Baglietto and Ninokata, 2004), turbulent flow structures and mixing across the narrow gap between rod bundle sub-channels (Chang and Tavoularis, 2008). Various CFD models have been adopted including RANS (Chandra et al, 2009) or URANS (Merzari et al, 2007(Merzari et al, , 2008 with different turbulent models k-ε (Baglietto and Ninokata, 2005), LES (Biemüller et al, 1996) and DNS (Ninokata et al, Thermal hydraulic considerations of nuclear reactor systems: Past, present and future challenges 13 2004; Baglietto et al, 2006). Applications of CFD for the prediction of two-phase flow velocity, sub-cooled boiling for void distribution in Krepper et al (2007b).…”

“…In these system analysis codes, the heat transport within the core can be accounted by means of correlations. However, the heat transfer correlations for liquid metals show a large spread as clearly demonstrated by Chandra et al (2009). CFD codes can be used to evaluate possible local effects which cannot be derived from system analysis codes.…”

Convection heat transfer of NaK-78 liquid metal in a circular tube and a tri-lobe channel

“…A challenge in performing CFD analyses of convection heat transfer for alkali liquid metals is their very low Prandtl numbers, which vary from $0.003 to 0.008, depending on temperature [17][18][19][20][21]. The analyses of liquid NaK-78 flow in the uniformly heated circular tube and the tri-lobe channel in Fig.…”