A note on adiabatic two-phase flow maldistribution in a set of horizontal parallel minichannels with I-type and Z-type configurations

Abstract Two-phase flow from a conventional size flow header that gets split into a set of parallel minichannels finds numerous practical applications in situations where a high heat dissipation rate per unit volume is demanded. Distribution of the two phases into parallel minichannels determines the thermo-hydraulic performance of the entire cooling system. In the present study, trends of time-averaged void fraction and pressure drop are analyzed for a horizontal set of parallel minichannels, with air-water adiabatic two-phase flow in the plug and slug regimes, in I-type and Z-type configurations, by changing significant parameters like header diameter, channel diameter, and number of channels. Results show that the trends of void fraction and pressure drop on either side of the inlet/outlet flow header for an I-type configuration resemble those for a U-type configuration. For both I-type and Z-type configurations, time-averaged void fraction and pressure drop show a more uniform trend when the two-phase flow is in the slug regime. Flow split is found to depend heavily on the geometry and the flow regimes rather than on the pressure drop.