A temperature dependent multi-ion model for time accurate numerical simulation of the electrochemical machining process. Part III: Experimental validation

摘要

The temperature distribution and shape evolution during electrochemical machining (ECM) are the result of a large number of interacting physical processes. Electrolyte flow, electrical conduction, ion transport, electrochemical reactions, heat generation and heat transfer strongly influence one another, making modeling and numerical simulation of ECM a very challenging procedure. In part I [1], a temperature dependent multi-ion transport and reaction model (MITReM) is put forward which considers mass transfer as a consequence of diffusion, convection and migration, combined with the electroneutrality condition and linearized temperature dependent polarization relations at the electrode-electrolyte interface. The flow field is calculated using the incompressible laminar Navier-Stokes equations for viscous flow. The local temperature is obtained by solving internal energy balance, enabling the use of temperature dependent expressions for several physical properties such as the ion diffusion coefficients and electrolyte viscosity. In part II [2], the temperature dependent MITReM is used to simulate ECM of stainless steel in aqueous NaNO_3 electrolyte solution. The effects of temperature, electrode thermal conduction, reaction heat generation, electrolyte flow and water depletion are investigated and a comparison is made between the temperature dependent potential model and MITReM. In this third part, the theoretical model is validated against ECM experiments in a flow-channel cell. The model is further optimized by including the effect of metal hydration and non-linear polarization relations. A close match is obtained between experiment and simulation.