Calculation On Mechanical Model Of Symmetric Airfoil Blade And Its Force Analysis

Symmetrical airfoil is a widely type of airfoil in fluid machinery applications.The blade aerodynamic characteristics and hydrodynamic characteristics is closely related to the efficiency and the cavitation performance and life with the working machine.So researching the blade airfoil of force analysis is of great importance.This paper based on the symmetrical airfoil as the research object,and established mechanical model,and calculated the mechanical model for the stress,and analyzed two typical airfoils combine with CFD numerical simulation.The main research contents and conclusions are as follows:(1)Symmetrical airfoil mechanics model is established in the first place,the force is divided into non-circulation and circulation part,then the two parts are calculated respectively,get the normal force mathematical expressions,decomposition method to force to the vertical and horizontal direction,the direction of lift and drag.the lift force and drag force of non-circulation and circulation part is superimposed respectively,and combining the blade suction force,get the expression of blade lift and drag.The expression of the total force shows that the stress of the airfoil relate to angle of attack,wind speed and size.(2)In the process of the calculation,the displacement,velocity,etc.of the symmetrical airfoils can be transformed into the form of polar coordinates by Joukowski conformal transformation method,and can calculate the guide vane stress by the polar representation,this can reduce the calculation difficulty and simplify the calculation analysis process.Based on the lift and drag expression,we can get the lift coefficient and drag coefficient curve of airfoil by writing program.(3)Choose NACA0012,NACA0015 two kinds of typical symmetric airfoils.Using numerical simulation by CFD software,Through CFD numerical simulation analysis,got life and drag coefficient variation curve of two airfoil.(4)The calculated results compared with the results of numerical simulation and experimental test data,and analysis its the hydrodynamic characteristics and aerodynamic characteristics,it is verified is accurate of the established Mechanical model and stress the accuracy of airfoil.The results can be used as a symmetrical airfoil research reference,and lay the foundations for the study airfoils.