| Abstract [eng] |
Containment of nuclear power plants is the last safety barrier, limiting the outflow of radioactive substances into the environment in case of potential accident. During the Loss of coolant accident (LOCA) pressure and temperature of the containment atmosphere rapidly rise due to a large quantity of water vapor being dumped. If the parameters exceed design basis, the integrity of containment can be lost. The usage of the water sprays to monitor and control containment atmosphere parameters is a common strategy of the nuclear power stations. A water atomization in the containment causes multiple, closely-related thermal and hydrodynamic processes. A detailed analysis of these complex processes is very complex and requires a lot of time, because of the ongoing transitional phase transitions between a water droplet and a containment gas mixture. It is necessary and convenient to examine these complex processes individually. After getting a clear understanding of their patterns, it is possible to take into account the complexity of their interactions in a consistent sense of expanding the boundary conditions. This work is aimed at understanding the underlying processes of heat and mass transfer between a liquid droplet and a humid gas mixture of containment atmosphere. It is assumed that the injected water flow in the containment gas mixture is relatively small. Therefore, the influence of the droplet to the parameters of a humid gas mixture is neglected and assumed that they are constant. This allows to bring to the light the key factors which define the influence of humid gas mixture parameters to a droplet heat and mass transfer processes. The results of the study highlight the importance of the gas temperature, humidity and heating manner to the transitional phase transition on the droplet surface. |
