Numerical Study of the Steady-State Subchannel Test-Case with NEPTUNE_CFD for the OECD/NRC NUPEC PSBT Benchmark

Abstract

The multifield computational fluid dynamics (CFD) code NEPTUNE_CFD is applied to carry out a numerical study of the steady-state subchannel test-case of the OECD/NRC NUPEC PWR subchannel and bundle tests (PSBTs) international benchmark, focusing on the simulation of a subset of five selected experimental runs of the centered subchannel configuration. First, using a standard choice for the physical models and a constant, predetermined bubble diameter, the calculated void fraction is compared to experimental data. Besides, the mesh sensitivity of the calculated void fraction is investigated by performing simulations of three grid levels, and the propagation of the experimental uncertainties on the input parameters of the simulations is also studied. Last, calculation results with devoted models for the bubble-size distribution are analyzed. Their impact is visible on the subcooled run, giving void fraction closer to experiments than those obtained with a fixed bubble-size. Void-fraction distribution with bubble-size models is also shown to come closer to experiment for another run with a higher equilibrium quality.

Development and Implementation of CFD-Informed Models for the Advanced Subchannel Code CTF

“…Baudry et al [44] used the CFD code NEPTUNE_CFD to analyze the single-subchannel portion of the PSBT benchmark [49]. The predicted void fraction and bubble diameters were compared with available experimental data for a variety of CFD model variations, such as mesh size.…”

Vertical upward two-phase flow CFD using interfacial area transport equation

“…The interfacial area transport models have been benchmarked for boiling bubbly flows (Bae et al, 2008;Koncar et al, 2011;Baudry et al, 2012). The studies for benchmarking the interfacial area transport equation in the boiling bubbly flows are summarized in Table 8.…”

“…The combination of Ruyer's model and Reynolds stress transport model agreed with the experimental data better than other models. Baudry et al (2012) benchmarked the multi-field CFD code, NEPTUNE_CFD, using steady state sub-channel test data in the OECD/NRC NUPEC PWR sub-channel and bundle tests (PSBTs) international benchmark. They tested three bubble diameter models such as constant bubble diameter model, Yao and Morel's model (2004) and Ruyer-Seiler's model (Ruyer, 2008;Ruyer et al, 2007;Seiler and Ruyer, 2008) to compute the bubble diameter.…”