| Centrifugal pump has played an important role in the industrial and agriculturalproduction, especially in the water conservancy irrigation and drainage. As pump is morewidely used, the requirement on the hydraulic characteristics and running stability isbecoming higher and higher. The impeller is one of the important flow passage components incentrifugal pump, which affects the working performance of a pump directly. When workingin the flow media, the surfaces of the impeller blade are suffering not only the centrifugalforce produced by its rotation, but also impact from fluid under high speed condition. So itsstress distribution is complicated. Traditional design use statistical methods to get theimpeller’s empirical parameter, but don’t pay attention to the numerical simulation of the flowstate inside the impeller. Therefore, it is hard to find out a vivid and real stress distribution onthe blade surfaces, and then the design efficiency is low. Both computational fluid dynamics(CFD) and finite element analysis applied in the field of rotating machinery provide aneffective way for the analysis of internal flow field and structure design.In the paper,3d modeling of impeller, pump inner flow field simulation, static and modalanalysis and optimization on impeller geometric parameters are discussed.1stAccording tothe working condition, design and calculate the physical dimension of the main flowcomponents in pump, impeller and voluteincluded. By grid conformal transformation, draw2d block model of impeller in Auto CAD. Pick up the key points on the surface of the bladefrom2d block model drawing. Establish the three-dimensional solid-model of the impellerand volute in Pro/E; use the surface analysis tool to check the surface quality of twisted bladesand modify the place where did not meet the requirements of fairing. Thus, the model ofimpeller would be more reasonable and accurate. Build the pump’s flow model, which lay thefoundation for the analysis of the flow field.2ndIntroduce theories and methods about theinterior flow numerical simulation of the centrifugal pump; mesh the flow model and set theboundary conditions in ICEM CFD. Import the grid which is well-defined into FLUENT,solve internal flow field of centrifugal pump. Then centrifugal pump inner flow pressure andvelocity distribution can be acquired well and truly. Output the pressure distribution data onthe blade surfaces.3rdMade a fluid-structure interaction analysis on centrifugal pump afterbuilding structure of flow field analysis and mechanical analysis in the Project Schematic of Workbench.Load the data about pressure finished in the former flow field analysis on theblade surfaces, made a static analysis to view stress distribution on the impeller under thecondition of both centrifugal force and water pressure. Then made a model analysis to viewfrequency and vibration characteristics of the impeller at design condition andestimate if itproduces resonance with the surrounding environment. The calculation results show that theimpeller under the design condition is well-operated.4thTo minimize the energy loss (diskfriction loss, hydraulic loss and bulk loss) and shaft power, a multi-objective function wasestablished and compiled to M-file. Define the main physical dimensions which affecthydraulic performance (such as the impeller diameter, blade outlet width and angle) as designvariables, and then determine the value range of variables. By using MATLAB optimizationtoolbox, the optimal design parameter combination under the reasonable head and flow rateare got. According to the back calculation with the optimized parameters of the impeller, theefficiency of the centrifugal pump increased than before by3.2percent.In sum, numerical simulation and finite-element analysis were applied to physical designand analysis of the impeller. It is significant and constructive to improve the security andreliability of the impeller, shorten the design cycle and reduce the manufacturing cost. |
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