Investigation on multi-physical field simulations of blade ECM using vertical flow

Abstract

Electrochemical machining (ECM), an advanced manufacturing technology, is widely used in aero-engine blades machining. In traditional ECM, the electrolyte flows through the inter-electrode gap (IEG), generating hydrogen bubbles and heat, which affect the conductance and thus influence the machining quality. This paper focuses on the effect of bubble movement on the flow field and the machining quality of ECM. A novel vertical flow mode of electrolyte is proposed according to the bubbles dynamics analysis. Multi-physical fields simulations of blade ECM using vertical and horizontal flows were carried out. With an initial gas void fraction, flow rate, and temperature at the inlet of 0, 19.7 m/s, and 302.65 K, respectively, in both flow modes, the vertical flow reduces the gas void fraction, flow rate, and temperature at the outlet by 2.4%, 0.4 m/s, and 0.6 K, and increases the conductance by 0.47 S/m. Thus, the vertical flow of the electrolyte is beneficial in reducing the gas void fraction and controlling the temperature rise, while enhancing the conductance. Then, the corresponding experiments using a vertical flow were carried out. The maximum machining deviation ranges from 3.4 to 75.6 μm and surface roughness Ra < 0.35 μm. The machining quality is high and the variation observed in the experiments is consistent with the simulation results, the validity and correctness of the simulations are verified. Thus, the vertical flow mode proposed in this paper is appropriate, can be used for other complex structures in ECM.