Mathematical modeling of the phenomenon of repeat filling in a system of parallel heat channels

A comprehensive model is proposed to describe the main flow regimes (flow of a subcooled liquid, bubbly flow, annular flow, mist flow, and the flow of superheated vapor) and the main regimes of heat transfer (convective heat transfer, heat transfer in the region of developed nucleate boiling, and supercritical heat transfer). In the description of the annular regime, the velocity of the film was calculated from a momentum equation which includes the friction between the film and the flow core. Allowance was also made for the evaporation of vapor from the film, the evaporation of drops, the separation of drops from the film, and the deposition of drops on the film. A two-temperature model which considers heat exchange between the vapor and the drops and the removal of heat by drops in collisions with the heated surface is proposed to describe the mist flow regime. The model is used to analyze the phenomenon of repeat filling in single heated channels and in a system of parallel channels. A model is also proposed to describe the motion of the repeat-filling front. A study is made of the change in the rate of flow of the heat carrier in channels over time, the change in the temperature of the heated surface over time, and the change in the temperature of the heated surface over the space coordinate during repeat filling.