Abstract

The subject of the study is to present the possibility of the use of visualization techniques in the researches on two-phase flows, carried out by the authors for many years. These works included as follows: heat transfer during the flow boiling, boiling crises and condensation in flow. The issue of the heat transfer intensification during the flow boiling through the channels of small diameters was analyzed. All this work focused on the minichannel geometry and, for the most part, on the cylindrical cross sections. Currently, it is planned to extend the research on the minigap geometry, including the possibility of intensification of heat exchange in this geometry. The intention of the project is to combine this work with a broad research on thermosyphon circulation (CLT), which is also a major concern for the industry. For this purpose, the use of a model minigap exchanger as an evaporator for thermosyphon circuit is planned. Visualization techniques, including thermal imaging, haven't been frequently used in studies on two-phase flows yet. Meanwhile, they have a number of advantages compared to traditional measurement methods and are worthy of attention, despite of the specific conditions that must be met for their effective use. The main advantages are: the possibility of registering the continuous process and its variability over the time, simplification of the issues of measurement errors (uniform measurement error at any point in the case of thermal imaging), and - in relation to contact methods - the elimination of thermal bridges (ribs). It is planned to extensive use of visualization techniques. These techniques seems to be particularly useful, because, in the natural way, allows to study the phenomenon in two-dimensional distribution, which is characteristic for minigaps.

Authors (2)