摘要：Two‐phase flow in parallel minichannels finds a number of applications. Maldistribution between parallel channels reduces both the thermal and fluid‐dynamic performances. To reduce the maldistribution effect, it is important to have information about the phase split in individual channels. The present study brings out the effects of various parameters like the channel diameter, number of channels, two‐phase flow regimes, and void fraction on the flow split in two‐phase flow inside a system of parallel channels for a U‐type configuration. Experiments are carried out with the plug and slug regimes typical to minichannel flows. High speed photography is used for flow visualization and the pressure drop values in individual channels are measured with a differential pressure transmitter to quantify maldistribution. The time averaged void fraction is found using an image processing technique. A counterintuitive non‐monotonous distribution of the void fraction in the channels brings out the fact that in two‐phase flow splitting, the relative distribution of the two phases does not depend on pressure drop alone. Flow configuration and the two‐phase flow regime in the header play a key role. An analysis with the existing separated flow model modified for minichannels reveals that although it is possible to estimate the orders of magnitude with respect to splitting, better splitting models still need to be developed. An empirical correlation for variation of the normalized pressure drop in the parallel minichannels, as a function of dimensionless distance along the header, is developed for each of the investigated flow regimes.Void fraction trends for adiabatic two‐phase flow in parallel minichannels with a U‐type configuration.
