Temperature characteristics of penetration flow into a branch pipe causing thermal fatigue at a T-junction

Abstract

The distribution of fluid temperature near a branch pipe wall of a T-junction was investigated for the flow pattern of impinged penetration where the hot main flow impinged on the branch pipe wall and penetrated into the branch pipe. The velocity in the inlet of the main pipe was fixed at about 10 m/s and the inlet velocity of the branch pipe was changed in order to simulate the flow pattern. The fluid temperature near the pipe inner surface fluctuated due to the penetration of the hot main flow. The fluctuations, with a frequency range of 0.2 Hz to 2 Hz, caused relatively large temperature fluctuations. The time averaged temperature decreased monotonically in the upward direction of the branch pipe axis. In contrast, the temperature fluctuation range had a peak at a distance from the nozzle corner when the flow velocity in the inlet of the branch pipe was relatively low. It is important to consider the peak position of the temperature fluctuation range when designing the length of the thermal sleeve.