Natural Convection in an Enclosure Containing Air and Hydrogen

ABSTRACT

Hydrogen may be released into a compartment of nuclear reactor containment during a core degradation accident. Hydrogen, being a light gas, will initially be stratified at the top of the compartment. After some time, this stratified layer may diffuse and form a homogenous mixture with air in the compartment. Classical heat transfer correlation may be used to obtain heat transfer coefficient for heat transfer from a homogenous mixture of air and hydrogen to the compartment boundaries. However, physical properties of the mixture need to be evaluated to obtain the heat transfer coefficient using the conventional correlation. In this paper a correlation is proposed in terms of the conventional correlation based on Rayleigh number and Nusselt number of air and a modification factor based on the mole fraction of hydrogen in the mixture. This correlation is easier to use when physical properties of the mixture like density, viscosity, specific heat capacity and thermal conductivity are not available. An inhouse code HDS, which has well validated subroutines to calculate mixture properties, has been used to carry out numerical simulations and establish this heat transfer correlation.

---

Full Text (PDF)

© 2010 Research Publishing Services