Local current densities in a two rotating disc electrode system with an axial electrolyte inlet measured by an autoradiographic method

The distribution of local current densities in a rotating electrolyser with axial electrolyte inlet in a laminar flow regime was studied by the autoradiographic method. With all systems studied, the local current density decreased monotonically from a maximum value at the inner to a minimum at the outer boundary of the electrode. Experimental results are compared with the numerical solution of the convective diffusion equation by the finite element method.Nomenclature a, b constants - c concentration - c₀ concentration in the bulk phase - d optical density - D diffusion coefficient - F Faraday constant, 96 487 C mol^–1 - h interelectrode distance - j local current density - J_{n, dif} density of diffusion flux in outer normal direction - n number of electrons transferred in the elementary step - diffusion flux - Q volume rate of flow - r radial coordinate - r₀ inner electrode radius - r₁ outer electrode radius - r_v radius of inlet orifice - r_d outer disc radius - t time - v_r radial velocity component of liquid - v_z normal velocity component of liquid - z normal coordinate - thickness of the layer in which the equation of convective diffusion is solved - v kinematic viscocity - angular velocity