Developing Adiabatic Two Phase Flow in Headers

Heat exchangers with microchannels (hydraulic diameter less than 1mm) are attracting significant attention lately. Performance of these heat exchangers, evaporators mostly, are greatly affected by imperfect distribution of a two-phase fluid to each channel. This paper presents overview of the issue, shows basic option to evenly distribute single and two-phase fluid, and methods to determine maldistribution. Special attention is given to describing two-phase regimes in an adiabatic horizontal header with R134a as a fluid, describing a two-phase map with area of good distribution.Copyright © 2003 by ASME