The wall electrode sensors have been widely used in the measurement of transport process.However,the theoretical equations in prior work did not include the effect of mass transfer to the edge of wall probe.This effect will bring an important contribution to the electrode current if the probe is small enough,which a lager measuring error if the original equation is used.This paper gives some modified equations in which the effect of mass transfer to the probe edge is considered.The experiment results pressented have supported these equations.
Under the existence of ionic migration effect, the differential equation describing mass transfer to stagnant point and its solution are deduced. Then the mathematical relation between current of measuring probe and liquid velocity is obtained. All the results in this paper can be also applied to the case without ionic migration effect. The theoretical result is verified by the experiment in which the ionic migration effect is changed by different concentrations of supporting electrolyte.
