Effects of continuous wavy ribs on heat transfer and cooling air flow in a square single-pass channel of turbine blade
Effects of continuous wavy ribs on heat transfer and cooling air flow in a square single-pass channel of turbine blade
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DOI：
10.1016/j.ijheatmasstransfer.2018.01.004
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发表时间：
2018-06
影响因子：
5.2
通讯作者：
Longfei Wang;S. Wang;Fengbo Wen;Xun Zhou;Zhongqi Wang
中科院分区：
文献类型：
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作者：
Longfei Wang;S. Wang;Fengbo Wen;Xun Zhou;Zhongqi Wang
提出了一种结构简单的波纹肋用于涡轮机叶片内冷通道，以强化换热，降低压力损失。采用数值模拟方法研究了单通道、静止通道内波纹肋片的换热性能和流动特性。通道宽度为12.7 mm，纵横比为1。在优化设计中，对波纹肋的4个主要几何参数：肋高（he= e− 3e）、肋圆角半径（r= 0-5 mm）、肋角（α= 20-55°）和肋厚（th= 0.5e− 2 e）进行了研究。此外，还探讨了潜在的高性能波形肋。研究的雷诺数为10，000 - 40，000。同时，选取了典型的45° V形肋作为波纹肋的参考方案，该方案具有较高的传热改善效果。肋高度（e）和肋宽度均为1.58mm，肋间距P/e为10。在此基础上，分析了通道壁面（包括肋壁面和侧壁面）的传热性能和热工性能。结果表明，肋高、肋圆角半径和肋角对通道的传热和流动有较大影响，而肋厚的影响相对较小。换热性能和压力损失与肋高和肋角正相关，与肋圆角半径负相关。结果表明，高肋高和大肋圆半径的波纹肋具有更好的强化传热和降低压降的效果。波纹肋对冷却空气的导流作用是减少摩擦损失的主要原因。小的肋角既可以节省空间，又可以减小压力损失，有利于提高波纹肋的性能。与45° V形肋相比，高性能波形肋使肋壁Nu/Nu 0和肋壁面积分别提高了7-37%和28- 52%，而摩擦损失没有增加。结果表明，波形肋是改善内冷通道换热的有效方法。
A wavy rib with the simple structure is proposed for the internal cooling channel in turbine blade, in order to enhance heat transfer and reduce pressure loss. The heat transfer performance and flow characteristics of a single-pass, stationary channel with wavy ribs are studied by numerical method. The channel width is 12.7 mm, with an aspect ratio of 1. Four major geometric parameters of wavy rib, including rib height (he= e− 3e), rib round radius (r= 0–5 mm), rib angle (α= 20–55°) and rib thickness (th= 0.5e− 2e) are investigated in optimal design. Furthermore, the potential high-performance wavy ribs are explored as well. The investigated Reynolds number is 10,000–40,000. Meanwhile, the typical 45° V-shaped ribs which have high heat transfer improvement are selected as the reference scheme of wavy rib. Both the rib height (e) and rib width are 1.58 mm, and the rib pitch P/e is 10. From the results, flow behavior of cooling air is presented, then heat transfer performance and thermal performance of channel walls, including ribbed walls and side walls, are analyzed. The results show that the rib height, rib round radius and rib angle have great impact on heat transfer and flow of channel, while the influence of rib thickness is relatively small. Heat transfer performance and pressure penalty are positively correlated with rib height and rib angle, while negatively correlated with rib round radius. As a result, wavy ribs with high rib height and large rib round radius perform better in increasing heat transfer and decreasing pressure drop. The diversion effect of wavy ribs on cooling air is responsible for friction penalty reduction. Due to the advantages of saving space and reducing pressure loss, small rib angle is beneficial to improve the performance of wavy ribs as well. In comparison with 45° V-shaped ribs, high-performance wavy ribs induce that ribbed wall Nu/Nu 0 and ribbed wall area improve by 7–37% and 28–52%, respectively, without friction loss increasing. It is indicated that the wavy rib appears to be an effective method of heat transfer improvement in internal cooling channels.