Single- and Two-Phase Diversion Cross-Flows Between Triangle Tight Lattice Rod Bundle Subchannels -Data on Flow Resistance and Interfacial Friction Coefficients for the Cross-Flow

Abstract

Single-and two-phase diversion cross-flows arising from the pressure difference between tight lattice subchannels are our concern in this study. In order to obtain a correlation of the diversion cross-flow, we conducted adiabatic experiments using a vertical multiple-channel with two subchannels simplifying the triangle tight lattice rod bundle for air-water flows at room temperature and atmospheric pressure. In the experiments, data were obtained on the axial variations in the pressure difference between the subchannels, the ratio of flow rate in one subchannel to the whole channel, the void fraction in each subchannel for slug-churn and annular flows in two-phase flow case. These data were analyzed by use of a lateral momentum equation based on a two-fluid model to determine both the cross-flow resistance coefficient between liquid phase and channel wall and the gas-liquid interfacial friction coefficient. The resulting coefficients have been correlated in a way similar to that developed for square lattice subchannel case by Kano et al. (2002); the cross-flow resistance coefficient data can be well correlated with a ratio of the lateral velocity due to the cross-flow to the axial one irrespective of single-and two-phase flows; the interfacial friction coefficient data were well correlated with a reynolds number, which is based on the relative velocity between gas and liquid cross-flows as the characteristic velocity.

Correlation for cross-flow resistance coefficient using STAR-CCM+ simulation data for flow of water through rod bundle supported by spacer grid with split-type mixing vane

“…The curve of Eqs. (42) and (43) which are the new models developed in the present work agree reasonably well in trend with the models proposed by Kawahara et al (2007). Appreciable differences in magnitude are however noticed in the predictions.…”

“…The cross-flow resistant coefficient obtained for pure cross-flow across rod bundle, given by Eq. (4) served as the maximum boundary for the present model and that of Kawahara et al (2007). …”

“…In their investigation, Kawahara et al (2007) correlated the cross-flow resistance coefficient for different ranges of axial velocity (u s ) For smaller axial velocity case of 0.5 ≤ u z ≤ 1.0 m/s, K was expressed as, K = 7.0 × 10 −3 u u z −1.91…”

Two-Phase Wall and Interfacial Friction Forces in Triangle Tight Lattice Rod Bundle Subchannel

“…Figure 7 shows prediction results by L-M method with Eqs. (6) and (10). The mean and r.m.s errors in the prediction are 4.90% and 14.7% for air-water system, while -0.08% and 14.4% for air-PLE one, respectively.…”

“…Results of such experiments and analyses are described in this paper. Figure 1 shows the cross-section of the present test channel, being the same as our previous studies (3)(4)(5)(6)(7) . The channel consisted of two identical subchannels, each surrounded by three partial rods in a triangular array.…”