Simulation Of Gap Flow Field Between Bamboo-Shaped Work Teeth Of Separate Cathode

It is necessary to alter the rotating speed of cathode according to the requirements of the angle change as the cathode is feeding along axial in the processing of mixed helix. The working-teeth and body being an integral whole in the traditional cathode, the angle of the rigid working-teeth can not be changed in the process of feeding, and can not be maintained consistent with the angle of the helix in processing, so the working-teeth will interfere with the side wall of the helix, resulting in the helix processed was broaden and inclined.To avoid the deficiency of the traditional cathode with fixed teeth in processing mixed helix, the design of the separate type cathode put forward, in which work part of the cathode was divided into 10 wheel plates. Micro-motor and reducer are placed inside the cathode body. The rotation of micro-motor is controlled by program which is compiled based on the bullet navigation equation. The wheel plates mesh with gears of different modulus and teeth, they are driven by the micro-motor through reducer,transmission shaft and gears, so the work tooth will always maintain consistent with the direction of the processing helix's spiral angle, However, The ladder shape surface of separate type cathode bamboo-shaped work teeth will influence gap flow field, and eddy current, separation, and cavitations will be formed, this will affect the final machining precision molding. Considering single-phase fluid flow around a cylinder vortex loss characteristics, with researching the influence of different shapes and sizes of hydrodynamic form on Strouhal Number St and Time-mean Resistance Coefficient CD, we determined the ratio range of downstream section and meet flow surface:0.6<a/b<2.8. On that basis, we proposed 6 different shape amendatory schemes to the cathode, established geometric models for each scheme in 3D, simulate gap flow fields for each scheme in 3D by COMSOL. The flow field pressure distribution and velocity distribution of each scheme were compared by simulation. According to the CD numerical value with calculation for each scheme, the best scheme is determined. There is not single-phase flow but gas-liquid two-phase flow in electrochemical machining gap. In order to prevent the occurrence of blockages in processing exit when pressure changed, the convergence diversion segment,length as 2mm, is added at the end of the cathode tooth. Software simulation results show that the pressure at the exit of machining clearance obviously increases after convergence diversion part added. It is proved that, the convergence diversion segment can play a role in preventing the occurrence of blockages.