Numerical Simulation Of Fluid-Structure Interaction In Axial Flow Pump

The axial flow pump has been widely used in farmland irrigation and water supply andsewerage works etc. It has the feature of large flow and low water head. With thedevelopment of the national economy, according to the characteristics of axial flow pump, alarge number of axial flow pumps will be used in some large national projects such as thesouth-to-north water transfer project. So it is important theoretical significance to research thestructural characteristics in an axial flow pump. In this paper, a model axial flow pump as theresearch object, Based on the model of multiple coordinate reference system in FLUENT, theN-S control equations, the Simple algorithm as well as the standard kappa-epsilon turbulencemodel, we took FLUENT and ANSYS Workbench coordination simulation method tosimulate the flow of the axial pump full passage. The fluid-solid coupling finite elementequations have been established according to fluid dynamics and elasticity. With theWorkbench data transfer technology, fluid-solid coupling calculation for the axial flow pumpimpeller has been done.This paper used three-dimensional modeling software UG to set up the solid model andfluid model of axial flow pump, and then imported the fluid model to the FLUENTpreprocessing software Gambit to prepare for the pre-treatment. By the FLUENT module inthe ANSYS Workbench, flies after processing were simulated and got the pressuredistribution of the flow field. Through the Workbench coupling technology, transporting thepressure of the flow field to the static analysis module and modal analysis module, calculatingthe action of fluid-solid coupling in the solid model of the axial flow pump impeller, to getimpeller stress distribution and order frequency and mode shapes. Through solution resultsreceive the following conclusions:1. The flow field pressure of Axial flow pump full passage gradually increased from inlet tothe outlet, the pressure of impeller front face is higher than the back face, the back of impellerblade near the inlet side of blade appeared obvious area of low pressure, so in this areacavitations phenomenon is prone to appear due to the decrease of pressure. Compared theflow field pressure distribution of axial flow pump in different flow conditions, finding thatflow distribution position and size of the pressure have some impact but the impact is small.2. The structural analysis results show that stress concentration occurs in the blade and thehub junction, and the maximum equivalent stress appears in the same position, but themaximum deformation is to occur at the outer edge of the blade outlet.3. From the modal analysis results, we know that the centrifugal force produces the torsiondeformation, and have a significant effect on the frequency, while the flow field pressure isnot obvious impact on the frequency. Each vibration mode figure shows that impeller at different frequencies has appeared different vibration forms, and vibration become more andmore complex with increasing frequency. In order to avoid resonance which will lead tostructural damage, impeller should avoid working at the inherent frequency.Through the research which used fluid-structure interaction method to the structuralcharacteristics of axial flow pump, knows the flow field distribution in the axial flow pump,stress distribution of impeller and the natural frequency. It provides a theoretical basis for thedesign of axial flow pump.