Investigation On Trajectory Optimization And Dissolution Characteristic In Electrochemical Machining Of The Complex Diffuser Channel

Integral vane components which are represented by complex diffuser are the core components of aero-engine with high aerodynamic efficiency and good reliability,and become widely applied.However,it is very difficult to manufacture them on account of their narrow channels,twist shaps,complex directions and thin blades,which makes it a challenge to fabrication.Electrochemical machining(ECM)has become one of the major processing methods for the manufacturing of integral vane components in aero-engine.Spiral feeding ECM is an althernative methode for the manufacturing of complex diffuser because of its twist channels.Nevertheless,towards the top of the list is the issue of how to search the tool direction and rotation angle for its complex blade direction,when researchers optimize its tool trajectory.In addition to this,the influence of electrolyte on the electrochemical dissolution characteristic of material is also a problem that must be studied in the process of ECM.In this paper,lots of researches are carried out regarding tool trajectory optimization of complex diffuser channel with spiral feeding ECM and the electrochemical dissolution charaterise of its material.The major contents of this dissertation contain the following items:(1)The spiral feeding ECM method is applied according to the analysis of the features of twist blades and narrow channels.A particle swarm optimization(PSO)algorithm is degined for the problem of seachin suitable tool trajectory,including tool direction,feeding depth and rotaion angle,and an optimized-result is obtained by the use of this PSO.The borderline curves of tool cathode’s head face are extracted according to the feeding direction.After these,the details of rotation angle in each sections are studied on the purpose of minimize allowance difference.(2)The polarization characteristic and electrochemical impedance spectroscopy(EIS)of 1Cr11Ni2W2 MoV are studied in two typical electrolytes,including sodium chloride and sodium nitrate in aqueous solution by the application of electrochemical workstation.The passivation of 1Cr11Ni2W2 MoV in and sodium nitrate solution is analyzed.Finally,nitrate solution is selected as electrolyte.The polarization characteristic and EIS of 1Cr11Ni2W2 MoV in electrolytes of different concentrations are also studied,where the influence of high concentration sodium nitrate solution on compactness of passive film and rate of polarization current rise in sodium nitrate solution are discussed,which are the fundamentals of high concentration electrolyte.Besides,the polarization characteristics of 1Cr11Ni2W2 MoV in different temperature are also studied,which provide the reference of selecting temperature.(3)The fixture of SFECM is degined and applied for the manufacturing of complex diffuser,and experiments are carried out.The results indicate that the feeding position,directon and rotation angle obtained from the path optimization can be applied to manufacture channels with sufficiently uniform allowance.The 0.8 mm/min and 1 mm/min feeding rates are applied by the use of the tool cathode whose side faces are fully insulated,and the results indicate that the tool cathode with 0.8 mm/min feeding rates can manufacture qualified channels and the other where tool cathode is destroied and the hub has nodules cannot.After that,a tool cathode with incomplete insulation are designed and applied,which has 1 mm width,and and the results indicate that it supports 1 mm/min feeding rates.Finally,this tool cathode is used to manufacture all the channels of diffuser,and the results are conducive to the subsequent finish machining.