高サイクル熱疲労に関するT字合流管内温度変動特性の研究

抄録

A water experiment for thermal hydraulics in a mixing tee was performed to investigate thermal striping phenomena. Flow visualization, detailed temperature measurement using a movable thermocouple tree, and measurement of flow velocity using particle image velocimetry were carried out. The flow patterns of jet exiting from the branch pipe could be classified into (1) wall jet (2) deflecting jet and (3) impinging jet according to the inflow condition. The parameter experiments showed that the flow patterns could be predicted by a momentum ratio between the two pipes. Temperature fluctation intensity was high along the edge of the jet exiting from the branch pipe. Near the pipe wall, the intensity was high in the wall jet and the impinging jet cases. The velocity measurement showed that, in the wall jet case, the vortices were generated in the wake region behind the branch pipe jet like Karman vortex. This vortex was correlated with prominent frequency of the temperature fluctuation.