| Two phase flow, arises in two different ways, the boiling/condensing of fluid due to phase change within the tube or through the introduction of separated flows (i.e., air and water) which mix together. It is a predominant flow structure in chemical reactors and process industry heat exchange equipment. Prediction of two-phase pressure drop in evaporators, condensers, and two-phase refrigerant lines is important for accurate design and optimization of the systems. Most models are limited to a specific flow range and rely on other flow information (such as film thickness and void fraction), to be implemented.;In the present work, pressure gradient and film thickness will be measured in vertical and horizontal flow facilities. Work in the literature has shown that models that ignore flow regime effects on heat transfer and other flow mechanisms are limited in reliability. Flow regime maps will be obtained via high speed video analysis in both flow facilities.;The universal profile is assumed to be an accurate representation of the liquid film, however this has not been substantiated directly. Local mean velocity profiles will be obtained using particle image velocimetry techniques in both flow facilities. All of these data will be mechanistically analyzed in an effort to understand the fundamental behaviors in two-phase flow. |
