Numerical and analytical modelling of concurrent physico-chemical processes passing at the boundary of steel in a liquid-metal coolant leading to film formation

Abstract

We analyse an engineering model for a self-consistent calculation of the growth of an oxide film in circulation circuits with a heavy liquid metal coolant and concentrations of impurities (oxygen, iron, magnetite) from the point of view of possible uncertainty in determining the activity of oxygen. The modelling of thermohydraulic and physicochemical processes is based on solving the associated three-dimensional equations of hydrodynamics, convective-diffusive transport, and the formation of chemically interacting impurity components in the coolant volume and on the surface of steels. Model calculations of the influence of the uncertainty of oxygen activity on the rate and integral yield of iron, which under the given conditions of the oxygen regime after interaction with oxygen determines the appearance of magnetite. It is numerically demonstrated that in the saturation mode there is a model-independent characteristic, which is determined by the parabolic constant and thickness of the oxide film characteristic of steel. Understanding these processes is highly important for justification of loops with HLMC and steadiness of structural materials that are in contacts with HLMC.