Study on high cycle thermal fatigue in mixing tee; Evaluation of transfer characteristics of temperature fluctuation from fluid to structure

Kimura, Nobuyuki; Kobayashi, Jun ; Kameyama, Yuri*; Nagasawa, Kazuyoshi*; Ezure, Toshiki ; Ono, Ayako ; Kamide, Hideki 

In this study, water experiments (WATLON) were carried out to clarify the unsteady behavior of heat transfer under wall jet condition in the mixing tee. In experiments, heat transfer coefficients between fluid and wall in the mixing region were obtained from temperature measurements using thermocouples (movable tree type in fluid and embedded type in wall). To clarify the relation between the local velocity and the wall temperature, those were measured simultaneously by the Particle Image Velocimetry (PIV) and the thermocouple measurement, respectively. Sampling time of the velocity by the PIV and the temperature by the thermocouple were synchronized in the measurement. The experimental results showed that the heat transfer coefficient was from 2 - 6 time larger than the reference value predicted by the Dittus-Boelter correlation in straight pipes and was increased as the local velocity near the wall.