Session: 15-05: Double-Wall Internal Cooling

Submission Number: 177593

Flow and Heat Transfer Characteristics in a Double-Wall Cooling Blade Structure With Diamond-Shaped Pin Fins 

Double-wall cooling is considered to be the most promising cooling technology for the thermal protection of next-generation turbine blades, which integrates impingement, pin fins and film cooling, and circular pin fins are often considered. In comparison with circular pin fins, diamond-shaped pin fins can greatly reduce the stagnation effect when the lateral airflow hits the sharp leading edge. Thus, the diamond-shaped pin fins are tried to implant in the double-wall cooling structure so as to decrease the flow resistance and improve the flow velocity near the target surface of the impingement cavity. This study numerically investigates the cooling performance of a double-wall blade structure with impingement, diamond pin fins and film cooling under real engine conditions. Numerical results indicate that: (1) Diamond-shaped pin fins significantly reduce the pressure loss in the impingement cavity, the friction factor of the diamond pin fins configuration is 8.49% lower than the circular one’s under real operating conditions, with Re = 1.3×10⁵, mass flow ratio (MFR) = 10%, and mainstream temperature of 1588 K, coolant temperature of 344 K. As the MFR increases, the difference in friction factor between the diamond and circular pin fin configurations becomes progressively larger. (2) The external film cooling flow fields of the two configurations with diamond-shaped or circular pin fins show no significant difference. But at low MFR conditions, pronounced film ingestion and large recirculation zones are resulted in because the coolant jet lacks sufficient momentum to overcome the adverse pressure gradient near the suction surface. (3) Under the aforementioned real conditions, the average external surface temperature of the metal blade increases gradually along the spanwise direction, with a maximum temperature difference of 35.5 K between the hub and tip. The highest temperature was located at the leading edge of the tip. Due to its more uniform internal heat transfer, the double-wall configuration with diamond pin fins exhibits a peak blade temperature that is 5.1 K lower than that with circular pin fins.

Presenting Author: Haoran浩然 Shen 沈 Xi'an Jiaotong University 习安交通大学

Presenting Author Biography: Haoran Shen is a Master's candidate in the School of Aerospace Engineering at Xi'an Jiaotong University, affiliated with the State Key Laboratory for Strength and Vibration of Mechanical Structures. His research focuses on internal cooling heat transfer, specifically employing numerical methods to analyze the flow and heat transfer characteristics within double-wall cooling structures featuring diamond-shaped pin fins.

Authors:

Haoran Shen Xi'an Jiaotong University
Yixuan Jia Xi'an Jiaotong University
Tianli Dong Xi'an Jiaotong University
Rongxia Feng Xi'an Jiaotong University
Wei Li Xi'an Jiaotong University
Junmei Wu Xi'an Jiaotong University