Wake effects on heat transfer from a turbine blade tip with different configurations and its corresponding shroud

摘要

The wakes that occur periodically owing to blade rotation, affect the HTCDs (heat transfer coefficient distributions) on the turbine blade tip and shroud. We investigated the wake effects on the HTCDs from the turbine blade tip with different configurations and the corresponding shroud. The NSM (naphthalene sublimation method) was used for measuring the local heat/mass transfer distributions (LHMTDs). Five different tip shapes were compared. The flow characteristics near turbine blade tip and shroud varied with respect to different tip shape. Especially, swirling flow and tip leakage flow patterns varied, which affected the HTD on the tip & shroud. In addition, the local heat transfer distributions (HTCDs) on the tip and the shroud varied with different tip configurations. However, when the wake effects were induced, the HTCDs on the tip & shroud became relatively uniform. Furthermore, the magnitudes of HTCDs on the tip & shroud were relatively similar in region of 0.3 < x/ C_x < 0.8. owing to the wake effect. Therefore, the vertical rib case can be the best-adopted for the turbine blade tip by considering the reduced total PLC (pressure loss coefficients) and HTCDs.