Design And Research Of Adjustable Guide Vane Mechanism Of Variable Geometry Turbine Guide Vane

Variable geometry turbine is one of the core components of the new aeroengine.When the fixed geometry turbine of traditional aeroengine encounters the change of working condition,it will lead to the change of high temperature and high pressure hot gas flow field inside the turbine,and the change of blade end clearance affected by temperature will increase the turbine power loss.The variable geometry turbine can change the area of the guide vane throat by changing the adjustment angle of the guide vane.The change of the area of the guide vane throat directly leads to the change of the flow capacity of the turbine,so that the variable geometry aeroengine with better performance can be obtained In view of this,a variable geometry turbine guide vane adjusting mechanism is designed in this paper.The kinematic and dynamic analysis of the mechanism was carried out.The main contents of this paper are as follows:(1)According to the task background and function requirements,the design requirements of the guide vane regulating mechanism are clearly defined,and the working environment,installation environment,loading condition and accuracy of the adjusting mechanism are determined.According to the parameters of the guide vane adjusting mechanism,the mechanical structure of the guide vane adjusting mechanism is designed.Use SolidWorks to build the three-dimensional model of the regulating mechanism,and draw the working drawings of each part of the regulating mechanism.(2)This paper analyzes the kinematic performance of the designed guide vane adjusting mechanism,establishes a virtual prototype in ADAMS,imports the SolidWorks model,sets the basic parameters in ADAMS,and carries out the kinematic simulation of the adjusting mechanism.Considering the actual working situation,the virtual prototype model established in ADAMS is simulated and analyzed,and the angle,angular velocity,angular acceleration and other characteristic curves of the variable geometry turbine guide vane regulating mechanism are obtained.The parametric modeling of the mechanism is carried out to analyze the influence of the size error of the parts on the accuracy of the mechanism,as well as the influence of the existence of the clearance between the moving pairs on the accuracy of the guide vane adjustment mechanism.F inally,the position reliability of the guide vane adjustment mechanism is analyzed and calculated.(3)The dynamic simulation of the variable geometry turbine guide vane regulating mechanism is carried out.First of all,the guide vane adjusting mechanism in variable geometry turbine is the mechanical structure of the whole rigid body,that is to say,simulation analysis is carried out without introducing the flexible body.When simulating in ADAMS,the aerodynamic load on the guide vane,the friction between the shaft holes and the joint bearings are added in advance to analyze their impact on the mechanical system.Using ABAQUS finite element software to create the MNF model of the key components,and then import it into Adams to simulate the rigid flexible coupling of the mechanism,and analyze the different dynamic characteristics of the two mechanisms in ADAMS.(4)By using ABAQUS,the thermal mechanical coupling analysis is carried out for the matching of guide vane shaft end.The dynamic simulation of the thermo mechanical coupling regulating mechanism in the real environment is carried out,and the influence of the thermal deformation of the bar on the motion characteristics of the guide vane regulating mechanism is analyzed under the typical working condition.The thermal mechanical coupling analysis of the steady-state temperature field of the mechanism is carried out by using ANSYS FLUENT software,and the sealing form and reserved clearance at the guide vane shaft under high temperature are determined through analysis and calculation.