Host: The Japan Society of Mechanical Engineers
Name : The 30th International Conference on Nuclear Engineering (ICONE30)
Date : May 21, 2023 - May 26, 2023
The characteristics of the axial evolution of interfacial structure in a narrow rectangular channel are expected to differ from that in other channel geometries because of the significant restriction from the wall. Moreover, the interfacial area concentration (IAC) is one of the essential structure parameters indispensable for predicting the two-phase flow. From this point, a visualization investigation was carried out to study the IAC of flow boiling in a narrow channel. The experiments were conducted in a narrow rectangular channel of 2 mm × 65mm × 700mm, heated by one broad side of the stainless steel for a better visualization from the other side. IAC along the flow direction was abstracted by the image processing method at three different flow rates: 0.08 m3/h, 0.12 m3/h, and 0.2 m3/h. Bubbly flow, churn flow, and annular flow were observed as the void fraction increased during the flow boiling in the narrow rectangular channel. The IAC lines along the flow direction showed an “N” shape during the development. At first, the IAC increased with the increase of void fraction. However, the IAC had a sharp decrease; the drop in the IAC was nearly 50%. And then it increased again until at the outlet. The drop interval was the transition from dense bubbly flow to churn flow from the visualization images. Combined with the void fraction and the bubble number density, IAC was analyzed by the bubble behaviors. The data in this study will be helpful for the development of the two-fluid model in narrow rectangular channels.
