Pressure Drop Experiments using Tight-Lattice 37-Rod Bundles

Abstract

In order to design a Reduced-Moderation Water Reactor (RMWR) core from a thermal-hydraulic point of view, an evaluation method on the pressure drop in a tight-lattice rod bundle is required. In this study, axial pressure drops in tight-lattice 37-rod bundles were measured under conditions of 2-9 MPa in exit pressure and 200-1,000 kg/(m 2 Ás) in mass velocity. The measured pressure drops were compared with calculated ones by the evaluation method with the Martinelli-Nelson's correlation. The comparison shows that a single-phase friction factor can be applied not only to a circular tube but also to a tight-lattice bundle except for an extremely small gap width. Then two-phase friction loss is a dominant component and accounts for about 60% of the pressure drop under an RMWR nominal operating condition. The evaluation method can evaluate effects of the flow area configuration (rod number, rod diameter, gap width) and axial power distribution under a wide range of flow conditions, and it can yield a good prediction of the pressure drop in a tight-lattice bundle.

Thermal Feasibility Analyses for the 1356MWe High Conversion-Type Innovative Water Reactor for Flexible Fuel Cycle

“…Confirmation to the prediction method for the pressure drop in the tight lattice rod bundles under steady state. For the pressure drop in the tight lattice rod bundles under steady state, JAEA seven-rod [12], 37-rod bundle [13] data and Toshiba seven-rod [14] and 14-rod [15] data were derived. The research showed the Martinelli-Nelson two-phase flow multiplifier [16] being applicable to the tight lattice rod bundles within an accuracy of ±10%.…”

Icone19-43913 Visualization of Two-Phase Interfacial Structures in Narrow Channel

“…Therefore, two-phase flow analysis for the dense-lattice bundle or narrow channel is needed, and the acquisition of experimental data and the modeling of the flow have been done in the past several years. Tamai et al (2006) evaluated the effect of the gap width and the power profile from the pressure drop measured in dense-lattice 37 rod bundles. Sadatomi et al (2007) studied the void fraction in a double subchannel with dense-lattice array and the data was compared with some correlations and subchannel codes.…”

Experimental Study of Three-Dimensional Void Fraction Distribution in Heated Tight-Lattice Rod Bundles Using Three-Dimensional Neutron Tomography

“…The void fraction distribution affects not only the BT but pressure drop and reactor characteristics. Therefore, JAEA carried out BT experiments with 37-rod bundles along with high pressure (2)(3)(4)(5) and void fraction experiments (6) . The purposes of the void fraction experiments were to elucidate liquid/vapor distribution and flow behavior in a tight-lattice rod bundle and to obtain a 3D void fraction database for the verification of a correlation and/or an advanced simulation code (7,8) .…”