Application of a non-uniform bubble model in a multiphase rotodynamic pump

Thus far, the break-up and the coalescence of bubbles have never been considered in the simulations of the multiphase pumps, while the non-uniform bubble model (NUBM) considered in this study has been successfully applied to predict the external characteristics, phase interaction and internal flow characteristics of a multiphase rotodynamic pump. On the basis of the Euler two-fluid model, the drag model considered to be the most important phase interaction model was modified using the secondary development technology of ANSYS CFX 16.0. The correctness of the modified drag model and that of the applied NUBM were verified by comparing with the experimental data at different inlet gas void fractions (IGVFs). When the IGVF was 21%, the relative errors of the pump heads with C_{D_0.34}, C_{D_SN}, and C_{D_modified} were 10.30%, 8.19% and 1.43%, respectively. Meanwhile, the comparative results with and without NUBM showed a small difference in the corresponding interphase forces (drag, added mass force, and lift) under the relatively small IGVF condition (IGVF = 3%), while the difference became obvious under a large IGVF condition (IGVF = 15%).