Method and apparatus for measuring underdeposit localized corrosion rate or metal corrosion rate under tubercles in cooling water systems

摘要

A method and apparatus is provided for measuring underdeposit localized corrosion rate of a metal structure under differential flow conditions encountered in actual cooling water systems. A first electrode defining a slow flow electrode (SE) is immersed in an electrolytic liquid (14). A second electrode defining a fast flow electrode (FE) is also immersed in the electrolytic liquid. Different fluid dynamic conditions are created on the slow flow and fast flow electrodes. In one embodiment, different fluid dynamic conditions are created by rotating the slow flow electrode at a first speed and by rotating the fast flow electrode at a second speed which is higher than the first speed. Three techniques are disclosed for obtaining measurement from a differential flow cell so as to determine the underdeposit localized corrosion rate due to differential flow conditions.