Study On Fluid-solid Coupling For Vibration Characteristics Of Axial-flow Pump Blades

Axial flow pump impeller is the core component of energy conversion for axial flow pump, and its safety and reliability directly relate to the safe operation of pumping stations. So study on fluid-solid coupling for vibration characteristics of axial flow pump blades has important influence on optimum design, stable operation and damage preventing of axial flow pump both in theory and actual fields. This dissertation mainly studied the rigidity and vibration characteristics of axial flow pump blade and the effect of deformed impeller to the lift, axial power and efficiency.The research object for this paper is the axial flow pump impeller which is to study the mechanical and mathematical models, stress analysis, boundary conditions and simplified load calculation and the imposed method according to the axial flow pump operating conditions. By using the ANSYS software for the structural analysis and calculation of the blade of axial flow pump. Take the structural characteristics of axial flow pump blades and the nature of the work into account and use 10 nodes SOLID92 unit to establish the finite element model for the blade in the course of structural analysis. Exert pressure on the load by considering the centrifugal force, gravity and the flow field generated on the blade. Put the blade into the simulation of the flow field of CFX software, and then calculate the water pressure on the blade, use the Parametric Design Language APDL to load it automatically by consider the distribution of water pressure related to fluid-solid coupling problem. After the completion of the load imposed on the blade ,obtain the stiffness and strength of the blade and modal and other mechanical properties of other important parameters, based on the vibration characteristics of intensity analysis of ANSYS software to the water pressure of the blade which under different conditions.The results show that the largest equivalent stress on the blade appears in the inlet side of the blade which has a larger change in gradient of stress and which is prone to fatigue failure; There is a certain degree of stress on the outer edge of the blade which makes the largest leaf deformation appears at the outer parts of the leaf and that is the sensitive areas of the blade vibration. There is little change that the impeller in the air mode or under water pressure and centrifugal force which means the water pressure and the centrifugal force have little effect on the impeller mode.