Hydrodynamic study of a liquid jet group in appliances with cylindrical distribution devices

Abstract

The analysis of existing studies regarding the process of steam condensation from a vapor-gas mixture on liquid jets allows us to conclude that the vast majority of them are experimental in nature, so the results of these studies can be correctly used only for the appropriate range of parameter changes of the liquid and gaseous phases. Also, the subject of research in them is mainly the hydrodynamic mode of a continuous liquid jet along its entire length. During theoretical and experimental studies, it was established that the shape of the jets flowing out of the cylindrical holes counter to the oncoming steam current differs from cylindrical shape, depends on the flow parameters, and is characterized by their rotation with intense wave formation on the jet surfaces. The jets are combined with each other with their subsequent disintegration along the current, dispersed and carried away with the steam current. Accordingly, it is incorrect to apply existing methods of heat transfer calculation to the analysis of heat transfer in this type of jets, only on solid jets of liquid, outside the investigated range of parameters. That is, using classical equations is impossible due to the complexity of calculating the cross-sectional area of jet groups flowing through cylindrical holes, and accordingly, the area of the heat exchange surface. Namely, it is impossible to use the traditional concept of the heat transfer coefficient as a parameter. Therefore, most of the existing calculation methods are based on using dimensionless complexes that describe the degree of change in the temperature of the liquid along the length of the jets under the appropriate geometric conditions. That is, without finding the limits of changes in the continuity of liquid jets, determining the limiting hydrodynamic modes using the existing methods of heat exchange calculation is incorrect.