Study on thermal striping phenomena in triple-parallel jet; Investigation on non-stationary heat transfer characteristics based on numerical simulation

Kimura, Nobuyuki; Kamide, Hideki ; Emonot, P.*; Nagasawa, Kazuyoshi*

A quantitative evaluation on thermal striping, in which temperature fluctuation due to convective mixing between hot and cold fluids causes thermal fatigue in structural components, is of importance for reactor safety. In this study, a water experiment of parallel triple jets configuration was performed in order to evaluate temperature fluctuation characteristics in fluid, transfer characteristics of temperature fluctuation from fluid to structure. The power spectrum densities of temperature fluctuation, furthermore, were in good agreements between the experiment and calculation. The calculated results showed that the heat transfer coefficient obtained from the experiment was appropriate and proper. The decay due to the heat transfer at the wall surface was dominant for the decay of temperature fluctuation at the neighborhood of the wall.