Mathematical Modelling of Software Failures

The problematic issues of modeling evaporation-condensation in the numerical study of non-stationary heat and mass transfer in cryogenic processes are considered. The statement of the problem of calculating the parameters of a multi-phase turbulent flow in a closed region is given when approximating the free surface by the liquid volume method, the use of which makes it possible to track the vertical displacement of the phase boundary in the process of changing the cryoproduct parameters over time. A description of evaporation-condensation models suitable for use in non-stationary calculations of flows in a closed region together with the liquid volume method is given. The possibility of using the Lee evaporation-condensation model and the model based on the law of particle diffusion is demonstrated as applied to calculations on simple computational grids. The results of calculations of the change in the pressure of a cryogenic product during non-drainage storage using various models of boiling-condensation are presented. The obtained simulation results were used in the accumulation of a database of storage parameters in the system for remote monitoring of the state of cryogenic equipment. The data are estimated storage times for various reference pressures and liquid levels in the vessel, with each external heat flux value having a specific estimated no-drain storage time.