Natural Convection's Transient Behavior

Transient response of a natural convection system is investigated by numerical simulation using FLUENT code. An integrator circuit analogy was recently proposed for natural convection systems. The proposed analogy was further confirmed by these recent simulations. New simulation results also suggest that a natural convection system acts as a "low-pass" filter for transients. Transmission characteristics of a natural convection system were investigated using sinusoidal temperature at the source-side boundary. Transient transmission factor was found to be a function of both fluid properties and the flow characteristics. Transmission factor was also found to be a strong function of fluctuation frequency. These results may prove a significant design tool for Generation IV natural convection systems, particularly for lead-cooled fast reactors or molten salt reactors.