Crossflow between interconnected subchannels in a multiple channel 3.Effect of pressure differential between subchannels on flow redistribution process

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Crossflow of a two-phase mixture between vertical subchannels is subdivided into three components in the literature; turbulent mixing, void drift and diversion crossflow. Of these, turbulent mixing alone occurs in an equiliblium flow, in which flow rates of both phases in each subchannel do not change in the axial direction. In a general non-equilibrium flow, however, all three components occur simultaneously. In this report, effect of pressure differential between subchannels on flow redistribution process along the channel axis has been studied experimentally. In the experiment, a multiple channel, consisting of two identical circular subchannels of 16 mm I.D., were used as a test channel. And, air and water were introduced unevenly into the two subchannels at the inlet to get several non-equilibrium flows with and without the pressure differential between subchannels. For each flow, we have obtained the axial distributions data of pressure differential between the subchannels, the air and water flow rates, the void fractions, and the tracer concentrations for both phases when gas and liquid tracers were injected into one of the two subchannels. From these experimental data, we have estimated lateral velocities of the air and water corresponding to each crossflow component, and analyzed the effect of the pressure differential on the lateral velocities.