Study on fluid mixing phenomena for evaluation of thermal stripping in a mixing tee

In order to investigate the thermal hydraulic behavior in a mixing tee, fluid temperature and flow velocity distributions were measured by a movable thermocouple tree and Particle Image Velocimetory (PIV). An in-house Direct Numerical Simulation (DNS) code, DINUS-3 was applied to understand mixing phenomena and also to confirm applicability in a mixing tee. The temperature and velocity fields obtained from the DNS were in good agreement with the experimental results. A prominent frequency of temperature fluctuation was calculated in the downstream region in the tee. It was also in good agreement with the experimental data. Measured velocity field showed vortex structure in the wake region behind the jet exiting from the branch pipe. The results of analysis showed that Karman vortex was generated in this wake region and it influenced the major temperature fluctuation in a mixing tee and also the prominent frequency. And the analytical results revealed that the vortices generated in the downstream region had axes in three directions and interacted with each other