Numerical investigations of fluid-structure thermal interaction phenomena at a T-junction of liquid metal fast reactor piping systems

Fluid-structure thermal interaction phenomena characterized by stationary random temperature fluctuations, namely thermal striping, are observed in the downstream region of a T-junction piping system in a liquid metal fast reactor. Therefore the piping walls located in the downstream region must be protected against the stationary random thermal process which might induce high-cycle fatigue. This paper describes the evaluation system based on numerical simulation methods for the thermal striping, and numerical results of the thermal striping in a T-junction piping system under the various parameters: velocity ratio and diameter ratio between both the pipes and Reynolds number. Then detailed turbulence mixing process at the T-junction piping region due to arched vortexes generating lower frequency fluctuations are evaluated through a separate numerical analysis of a fundamental water experiment. (author)