(1. Department of Mechanical and Transportation Engineering, China University of PetroleumBeijing, Beijing 102249, China; 2. CNPC Drilling Research Institute, Beijing 100195, China)
Abstract：To solve the problems, such as gasliquid separation in the impeller of a rotodynamic multiphase pump under high gas void fractions (GVF) and subsequent reduction in the pump performance, several methods for breaking gas packets to inhibit gasliquid separation and enhance the mixing between two phases were presented, including implanting short blades, using Tshaped blades, and opening holes on the blades where gas packets appear. Then, under the rated condition, the flow fields in three amended impellers were simulated under the GVFs of 60％ and 80％, respectively, by means of CFD codeFluent. The results show that the streamlines are more evenly distributed in all the amended impellers than those in the original one, the degree of mixing of two phases is improved greatly. Additionally, the local highest GVF in all the amended impellers is not only lower than that in the original impeller, but the GVF distribution in them is more uniform. Besides, a comparison of total pressure head rise across the original impeller and the amended ones was made. It was showed that the total pressure rise of the amended impellers is similar to the original one under low GVFs, but it is larger in high GVFs. The amended impeller with opening holes exhibits the highest head rise, which is even better than that of the original impeller, suggesting the means of opening holes not only enhances the ability of mixing of twophase but also prevent extra hydraulic losses furthest.
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