| The overall casing of the aero-engine is made up of segmented casings.It’s working environment is harsh and the external load is complicated,which leads to the air leakage at the joint of the flange.Greatly affect the efficiency of the aero-engine.At present,the research on sealing of the casing flange of aero engine is still in its infancy,so it is of great significance to study the sealing problem of the casing flange.In this paper,the bolted flanged connection of thin-walled casing is taken as the study object,the influence of the casing flange structural parameters and external load on the sealing characteristics of the casing flange was studied.Based on the annular plate theory,the relationship between the deformation of the casing flange and load such as axial force and internal pressure was deduced and established.Using finite element software Ansys Workbench to establish the casing finite element model,the axial displacement of the flange root and the separation distance of the joint face were calculated under different casing flange structural parameters and external load conditions.Compared with the theoretical results,the influence law of the casing flange structural parameters and the external load on the sealing performance of the casing flange was obtained.The response surface method is used to fit the error generated by the model simplification,and the established theoretical model was verified at last.The research shows that the axial displacement of the flange root increases with increasing internal pressure,axial force,and the casing flange height.Increasing the casing flange thickness and the bolt preload can restrain the increase of the axial displacement of the flange root.With the increase of internal pressure and axial force,the separation distance of the joint face increases,and decreases with the increase of the bolt preload;increasing the casing flange thickness within a certain range can reduce the separation distance of the joint face and the increase of the casing flange height will not affect the sealing performance of the casing flange to some extent.It is concluded that the relative error of the axial displacement of the flange root between the theoretical solution and the finite element calculation is-2.71%,and the relative error of the separation distance between the theoretical solution and the finite element calculation is-1.21%,which has a good engineering accuracy and provides an effective method for the analysis of sealing characteristics and leakage evaluation of the casing flange of aero-engine. |
