| Currently, the low specific speed centrifugal pump were widely used in kerosene, petroleum, chemicals, etc., but efficiency is not high.Now, due to the increasing global energy shortage, thereby increasing the centrifugal pump efficiency and reduce research costs become urgent. In recent years, with the development of CFD technology,the numerical calculation of the three-dimensional viscous flow field inside the impeller machinery has been relatively mature and achieved great achievements. In order to expand the application of CFD technology, it is no longer confined to the research and analysis of internal flow field of centrifugal pump, no longer confined to a centrifugal pump flow field research and analysis, and to the combination of optimization algorithm to improve the centrifugal pump efficiency, reduce flow loss.In this paper, combined with CFD technology has been optimized the centrifugal pumps for improving efficiency of centrifugal pumps, centrifugal pumps to improve efficiency to achieve the goal. As the key part of energy conversion centrifugal pump impeller flow components, carries on the optimization design has important significance of saving energy and reducing consumption. In this paper, based on the structural feature of low specific speed centrifugal pump, increasing efficiency as the goal, combined with genetic algorithm to find the best combination of outlet parameters of specific speed centrifugal KQNW200 / 400-75 impeller to obtain the optimal model of the impeller.Main research contents and results are as follows:1. Based on the performance and characteristics of low specific speed centrifugal pump impeller, establishing a optimization model with a loss Extreme as the target, setting constraints by mutual restraint between performance parameters of each pump impeller and hydraulic parameters. Using MATLAB genetic algorithm optimize the exporting geometry, get the best combination of parameters. And then re-hydraulic design the combination of parameters to obtain a new model, finally carry on the machine simulation of impeller, The results show analog value of centrifugal pump improves 3.85 m, the efficiency is improved by 2.83%. By comparing the pressure and speed chart on the mid-section of impeller, it can be seen the flow smoothly transited,whirlpool improved significantly.2. To study theinfluences of exit width on centrifugal pump performance, outlet width b2 value to b2 ± 1mm, b2 + 3mm, respectively. Then re-modeling and re-meshing the impeller, machine simulate multiple operating point performance curve. Bying comparing 0.8Q, 1.0Q, 1.2Q three operating points, analyzeimpeller and volute flow field to find exit width in a range of little change has inconspicuous on centrifugal pump performance. Using the same numerical model predict the changes in the number of leaves effect on the performance of centrifugal pumps.The same numerical model number changes affect the performance of centrifugal pumps of the blades to predict fluid from inside centrifugal impeller blade increases by the greater number of its forces and constraints, which led to its increased lift. Leaf number is too small, there will be centrifugal impeller inlet swirl, and the corresponding lower static pressure, prone to cause cavitation. Fluid from inside the centrifugal pump impeller blade increases by the greater number of its forces and constraints, which led to its increased lift. If leaf number too small, there will exsist swirl in the inlet of centrifugal impeller, and the corresponding static pressure is lower, prone to cause cavitation. |
