The corrosion rate of the inner surface of iron tubes was measured under turbulent flow conditions of air-saturated solution. The corrosion process was assumed to be controlled by mass transfer of oxygen dissolved, and the diffusion rate of oxygen was evaluated by the non-dimensional groups: Sh, Re, and Sc. The experimental results agreed well with the theory of mass transfer at the smooth surface when corrosion was relatively mild. On the other hand, the diffusion rate of oxygen was affected by the roughness of tube wall if corrosion was severe.
