The effect of inert region on mass transfer has been studied numerically for the cathode package that is used to measure the local mass transfer rate to a solid surface in a flow system. The inert region introduces a considerable error in the limiting current method as the region increased.
The overall mean Sherwood number on the cathodic electrodes with the inert region was correlated as follows.
Sh_m = 13.96Re^0.339 (1+RT)^0.444
when RT is the ratio of the inert region to the active region. If RT is less than 0.25, the error of theoretical value to Leveque solution is less than 12%.