Xu Liang, Xiong Yanh, Xi Lei, Gao Jianmin, Li Yunlong, Zhao Zhen
State key Laboratory of Mechanical Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
Guangdong Xi'an Jiaotong University Academy, Foshan 528000, China.
Entropy (Basel). 2019 Dec 22;22(1):15. doi: 10.3390/e22010015.
There are some inclined jet holes in the cooling structure of the leading edge region of gas turbine blades. In order to improve the cooling effect of traditional round holes, this paper proposes to replace the round holes with threaded holes, and studies the complex flow and heat transfer performance of the swirling impinging jet (SIJ) issuing from the 45° threaded holes in the inclined condition by numerical simulation. The influencing factors include jet inclination angle (45°-90°), jet-to-plate distance ( = 2, 4, 6), and Reynolds number (6000-24,000). The results show that the inclination angle and jet-to-plate distance have a great influence on the size, shape, and position of vortices in the jet space, while the Reynolds number has little effect on the vortices. In the inclined state, the impinging cooling effect of the swirling impinging jet is better than that of the circular impinging jet (CIJ), both heat transfer coefficients will degrade significantly when the inclination angle is 45°. When the inclination angle is greater than 45°, compared with the round hole, the enhanced heat transfer region for the swirling jet is in the region of r/d < 3, while both of the numbers in the wall jet region are weak, with a value of just 20. At the same time, with the increasing of the inclination angle (α > 45°), the average number on target surface holds a constant value. Under the inclined conditions, the heat transfer coefficient on the target surface for the swirling jet is increased totally with the increasing of the , but when the is larger than 18,000, the rate of enhanced heat transfer gradually weakens.
燃气轮机叶片前缘区域的冷却结构中有一些倾斜的喷射孔。为了提高传统圆孔的冷却效果，本文提出用螺纹孔取代圆孔，并通过数值模拟研究倾斜状态下从45°螺纹孔喷出的旋转冲击射流（SIJ）的复杂流动和传热性能。影响因素包括射流倾斜角（45° - 90°）、射流与平板距离（ = 2、4、6）和雷诺数（6000 - 24000）。结果表明，倾斜角和射流与平板距离对射流空间内涡旋的大小、形状和位置有很大影响，而雷诺数对涡旋影响较小。在倾斜状态下，旋转冲击射流的冲击冷却效果优于圆形冲击射流（CIJ），当倾斜角为45°时，两者的传热系数都会显著下降。当倾斜角大于45°时，与圆孔相比，旋转射流的强化传热区域在r/d < 3的区域，而壁面射流区域的两个 数都较弱，值仅为20。同时，随着倾斜角（α > 45°）的增加，目标表面的平均 数保持恒定值。在倾斜条件下，旋转射流在目标表面的传热系数总体上随着 的增加而增大，但当 大于18000时，强化传热速率逐渐减弱。
