Flow redistribution due to void drift in two-phase flow in a multiple channel consisting of two subchannels

Single- and two-phase turbulent mixing rate between adjacent subchannels in a vertical 2×3 rod array channel

“…Concerning experiments on the fluid transfer between subchannels, two-phase turbulent mixing (Petrunik and St. Pierre, 1970;Rudzinski et al, 1972;Singh and St. Pierre, 1973) and diversion cross-flow (Tapucu, 1977;Tapucu and Merilo, 1977;Tapucu et al, 1982) have been measured using a simpler channel made up of two-subchannels (i.e., two-subchannel system). Recently, Sadatomi et al (1994Sadatomi et al ( , 1995Sadatomi et al ( , 1996aSadatomi et al ( ,b, 1997, Sato et al (1996) and Kawahara et al (1997aKawahara et al ( ,b, 1998Kawahara et al ( , 2000a have studied two-phase fluid transfers for hydrodynamic equilibrium and non-equilibrium flows in geometrically simple two-subchannel systems, and measured the axial distributions of both gas and liquid flow rates and void fraction in each subchannel in order to extract each component from the total fluid transfer. So far, the data on the fluid transfer have been obtained only from two-subchannel systems.…”

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

“…However, there are few experimental data for the triangle tight lattice bundle to validate the code, especially for an inter-subchannel fluid transfer, which is one of key parameters in the subchannel analysis. The fluid transfer in a gas-liquid two-phase flow system has been modeled as three independent components; turbulent mixing, void drift and diversion cross-flow (9)(10)(11)(12) . Therefore, we have started an experimental program for studying each fluid transfer component.…”

Prediction of the Equilibrium Two-Phase Flow Distributions in Inter-Connected Subchannel Systems.

“…This hypothetical force, in the absence of a pressure difference between two adjacent subchannels, is assumed to work in a way that the two-phase flows in a rod bundle tend to redistribute and attain the hydrodynamic equilibrium flow conditions in the downstream region. Magnitudes of the force were estimated by Ninokata et al 4) in relation to an extent of the deviation from the equilibrium flow conditions which were provided experimentally by Sadatomi et al 5) in the interconnected two circular subchannel test sections.…”

“…In this section, we evaluate these models based on the Kumamoto University data. 5,6) A representative of these models is due to Lahey and described in the textbook by Lahey and Moody. 1) The model is used in many subchannel analysis codes to include the void drift effects and is given by;…”

“…In evaluating the pressure gradient, we make use of the hydrodynamic equilibrium flow distribution data obtained at Kumamoto University in the slug to churn-turbulent flow regime where the void drift phenomena are more conspicuous than the other flow regime. 5,6) It is one approach to treat the pressure gradient dp/dz as a parameter and to solve a set of Eqs. (5)- (10).…”