| A mixed flow desulfurization slurry pump of600MW in some power plant was taken as the research object in this paper. Because its output and efficiency could not meet the requirements of desulfurization in power plants, uprating of this pump was implemented. As the design of slurry pump transformation is complex, various factors should be taken into consideration. On the basis of the study on the theoretical performance of pumps, we try to find out the optimal transformation scheme. By enlarging outlet diameter, outlet angel and corners of the impeller appropriately, the pump head and flow were increased. Therefore, the desulfurization efficiency of power plants was enhanced.Pro/E, the three-dimensional modeling software, is used to construct the three-dimensional modeling of the pump before and after its transformation. The software Gambit was applied to the grid division of flow field. Besides, the multiphase flow model Euler, the standard turbulence model k-ε and algorithm SIMPLEC were selected to go with the numerical simulation software FLUENT6.2to simulate solid-liquid two-phase flow field inside the pump before and after transformation. Then the performance changes of the pump before and after transformation was studied, according to the distributions of the velocity, pressure and solid particle concentration in solid-liquid two-phase flow field. Simulation results show that the head and flow of the desulfurization slurry pump as well as the desulfurization efficiency all increased after transformation. Although the wear degree of impeller and volute tongue of the desulfurization slurry pump increased after transformation, the distribution of internal flow field was reasonable and the overall operating stability was better. Meanwhile, pressure distribution on blades was more uniform and anti-cavitation of pump has been improved. As are shown in the results of field measurements that both the output and desulfurization efficiency of pump have been greatly improved after transformation. The numerical simulation results were consistent with that of field measurements, which shows that the numerical simulation could predict and guide the study of pump performance and the practical transformation of engineering to some extent with reasonable model selection. |
