A comparative study of temporal evolution of air and steam bubbles emerging out from an orifice in a quiescent water media

TitleA comparative study of temporal evolution of air and steam bubbles emerging out from an orifice in a quiescent water media
Publication TypeConference Proceedings
Year of Conference2016
AuthorsAhmad.S T, Datta S, Singha SKumar, Datta SPrasad, Das PKumar
Conference Name9th International Conference on Multiphase Flow
Conference LocationFirenze, Italy
KeywordsDepartment of Mechanical Engineering
Abstract

Formation and evolution of a bubble or a train of bubbles from an orifice in a quiescent liquid media has a great importance in multi-phase flow and phase transformation. The bubble can be of either stable phase in case of gas bubble or metastable phase in case of vapor bubble. Using high-speed photography, a comparative analysis between the temporal variation of the evolution of air and steam bubbles emerging out from a small-diameter tube in a quiescent water media has been discussed in the present experimental study. Various intriguing patterns in the bubble shape, evolution, and merging are observed from the experiments. The evolution of steam bubbles are found to be more complicated than that of the air bubbles due to the occurrence of the vapor-liquid phase transition. Moreover, the final stable phase in the bubble evolution and the phase of the liquid as the media are the same, i.e. water, so, the steam bubble ultimately mixes in the water media and eventually disappears. However, this kind of transformation cannot be observed in case of air bubble due to the absence of phase transition throughout the process. The bubble evolution is also studied for different flow rates of air or steam.