New Interfacial Drag Force Model Including Effect of Bubble Wake, (II)

Abstract

In the previous study, we proposed a new interfacial drag force model based on experimental data of steam-water bubbly flow in a large-diameter pipe. This is because our experimental results had suggested that effect of bubble wake should be included in the interfacial drag force model, although it had not been taken into account in the existing models. A preliminary method for including the effect of bubble wake was hence developed and used in the new model. A new bubble size prediction method was also adopted in the model. In the present study, after improving the measuring equipment and signal processing procedure, another series of experiments was carried out. Using the new experimental data, the methods of predicting bubble size and effect of bubble wake were slightly modified. To test the validity of the new model, predicted results were compared with available experimental data sets of steam-water bubbly two-phase flow in large-diameter pipes. One-dimensional and two-dimensional two-fluid models were used for the calculation. Comparisons showed that the new model is in good agreement with the experimental data, whereas the model which does not take into account the effect of bubble wake overestimated the void fractions.