On the Flow Structures and Adiabatic Film Effectiveness for Simple and Compound Angle Hole With Varied Length-to-Diameter Ratio by Large Eddy Simulation and Pressure-Sensitive Paint Techniques
On the Flow Structures and Adiabatic Film Effectiveness for Simple and Compound Angle Hole With Varied Length-to-Diameter Ratio by Large Eddy Simulation and Pressure-Sensitive Paint Techniques
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大涡模拟和压敏涂料技术研究变长径比简单复合角孔的流动结构和绝热膜效应
DOI：
10.1115/1.4037085
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发表时间：
2017
影响因子：
--
通讯作者：
Hongde Jiang
中科院分区：
文献类型：
--
作者：
Weihong Li;Wei Shi;Xueying Li;Jing Ren;Hongde Jiang
从实验和数值角度研究了孔长径比和复合角对平板气膜冷却效果的影响。使用压敏涂料 (PSP) 技术，对 0.3 至 2 的七种吹气比 (M)、0.5 至 5 的五孔长径比 (L/D) 和两种复合角（β：0° 和 45°） 进行气膜冷却效率测量。结果表明，无论复合角度如何，L = 0.5 和 1 的离散孔都显示出最高的气膜冷却效率。圆孔通常随着L从2增加到5而呈现增加趋势，而复合角孔则呈现与吹气比（BR）和长径比相关的复杂趋势。复合角度通过高吹气比和长径比提高了气膜冷却效率。在并行工作中，采用大涡模拟（LES）方法来求解流场并可视化管内和主流区域的涡结构。结果表明，在时间平均流场中观察到的反向旋转涡对（CRVP）起源于具有不同吹风比和长径比的不同涡结构。还研究了标量场传输特征，以阐明不同的涡流结构如何影响温度分布和薄膜冷却效率。
The effects of hole length-to-diameter ratio and compound angle on flat plate film cooling effectiveness are investigated from an experimental and numerical view. Film cooling effectiveness measurements are performed for seven blowing ratios (M) ranging from 0.3 to 2, five-hole length-to-diameter ratios (L/D) from 0.5 to 5, and two compound angles (β: 0 deg and 45 deg) using pressure-sensitive paint (PSP) technique. Results indicate that discrete holes with L = 0.5 and 1 show highest film cooling effectiveness regardless of compound angle. Round hole generally shows an increasing trend as L increases from 2 to 5, while compound angle hole shows a complex trend concerning with blowing ratios (BRs) and length-to-diameter ratios. Compound angle enhances film cooling effectiveness with high blowing ratios and length-to-diameter ratios. In a parallel effort, large eddy simulation (LES) approach is employed to solve the flow field and visualize vortex structures of intube and mainstream regions. It is demonstrated that the counter-rotating vortex pair (CRVP) which is observed in the time-averaged flow field is originated in different vortex structures with varying blowing ratios and length-to-diameter ratios. Scalar field transportation features are also investigated to clarify how different vortex structures affect the temperature distribution and the film cooling effectiveness.