Flow Split Relationships in Two-Phase Parallel Channel Flows

The observed flow combinations through the channels were: cocurrent upflow in both channels, cocurrent upflow in one and countercurrent flow in the other channel, and cocurrent upflow in one and single phase liquid downflow in the other channel. The flow regimes in each channel varied from churn-turbulent, through anular flow, to chugging counter-current flow, as the flow conditions were varied. It was observed that the flow combination obtained was history dependent. However, for given flow combinations, certain flow split relationships were established. With both channels in cocurrent upflow, the flow quality into each channel was approximately the same as the flow quality in the lower plenum at the flow split elevation. For the other flow combinations, a simple relationship between the void fractions at the bottom of the channels which had two phase fluid, and the average void fraction and vapour flux in the lower plenum at the flow split elevation, was established.