Abstract Detached eddy simulation (DES) has been carried out to study a three-dimensional trailing-edge (TE) cutback turbine blade model with five rows of staggered circular pin-fin arrays inside the cooling passage, in order to evaluate the cooling performance in relation to coolant ejection slot angle. Simulations were performed by adopting a shear-stress transport k-ω turbulence model, and the effects of three different ejection slot angles 5°, 10° and 15° were investigated in terms of the characteristics of adiabatic film-cooling effectiveness, coefficient of discharge, and vortex shedding frequencies, respectively. The results obtained have shown that the TE cutback blade cooling with a 5° coolant ejection slot angle produced a better heat transfer coefficient than the other two ejection slot angles tested. The distributions of adiabatic film-cooling effectiveness along the cutback walls were found to be sensitive to the coolant ejection slot angle, e.g. the increase of ejection slot angle to 15° yielded near unity of cooling effectiveness along the entire breakout walls, whereas the decrease of ejection slot angle caused a drastic decay of cooling effectiveness after the maximum effectiveness has been reached. Of the three angles studied, a TE cutback blade model with a 15° ejection slot angle produced an optimum film-cooling effectiveness. In the breakout region, vortex shedding was observed along the shear layer between the hot gas and the coolant airflow. The shedding frequencies were evaluated to be 2.93, 2.21, and 2.18 kHz for the ejection slot angles of 5°, 10° and 15°, respectively. The findings from this study could be useful to improve existing TE cutback turbine blade design to achieve optimum film-cooling performance.

中文翻译：

---

不同喷射槽角度下叶片后缘冷却性能的分离涡模拟

摘要 采用分离涡模拟（DES）研究冷却通道内具有五排交错圆形针翅阵列的三维后缘（TE）后切涡轮叶片模型，以评估其冷却性能。冷却液喷射槽角度的关系。采用剪应力输运k-ω湍流模型进行模拟，研究了5°、10°和15°三种不同喷射槽角对绝热膜冷却效率、排放​​系数等特性的影响和涡旋脱落频率。获得的结果表明，具有 5° 冷却剂喷射槽角的 TE 缩减叶片冷却产生比其他两个测试喷射槽角更好的传热系数。发现沿后切壁的绝热膜冷却效率的分布对冷却剂喷射槽角敏感，例如喷射槽角增加到 15° 沿整个突破壁产生接近统一的冷却效率，而减少在达到最大效率后，喷射槽角度导致冷却效率急剧下降。在研究的三个角度中，具有 15° 喷射槽角的 TE 缩减叶片模型产生了最佳的薄膜冷却效果。在爆发区，沿着热气和冷却剂气流之间的剪切层观察到涡流脱落。对于 5°、10° 和 15° 的喷射槽角，脱落频率分别评估为 2.93、2.21 和 2.18 kHz。