Numerical prediction of two-phase-flow pump performance by a bubbly flow model with fixed cavity

Effects of outlet blade angle and rotational speed on the two-phase-flow pump performance are discussed based on the results calculated by a three-dimensional bubbly flow model with fixed cavity. Critical volumetric flow ratio of air to whole fluid, at which the fixed cavity on the shroud near the impeller inlet section expands rapidly to fill the section, decreases with an increases in the outlet blade angle and increases with an increase in the rotational speed. To predict the theoretical head for the higher volumetric flow ratio, the one-dimensional two-fluid model by Furuya is also applied and modified for low-specific-speed pumps. (author)