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Experimental Heat Transfer of Rib Roughened Square, Rectangular and Trapezoidal Cooling Channels.

机译：肋粗糙的方形，矩形和梯形冷却通道的实验传热。

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摘要

This paper explores the heat transfer benefit of using turbulators within turbine airfoil cooling passages. The local and average heat transfer coefficients were measured in scaled models with trapezoidal, square and rectangular cross-section channels with aspect ratios of 0.15, 1, and 3 respectively. The friction factors through the square and rectangular channels were also calculated. To simulate a heated wall boundary condition, heaters were placed along the test section. Liquid crystals were mounted over the heaters to measure the temperature. For the square and rectangular test sections, the walls are rib-roughened on two opposite sides with and without wrap-arounds extending on the adjacent walls. For the trapezoidal test section, the walls have staggered turbulators mounted on two opposite sides with film bleed holes on one side. Comparisons are made for turbulator configurations where the height-to-hydraulic-diameter ratio (e/Dh) is 0.09 and 0.14; the turbulator height-to-width ratios (e/w) are 0.45, 0.63, and 0.73. Upon conclusion of this study, it was found that: (a) Based on the results from the square and rectangular channel studies: (1) Having wrap-arounds result in a heat transfer benefit to all of the channel walls and increases the friction factor. (2) The Nusselt Number increases as the flow travels from area one downstream towards area five. (b) Based on the results from the trapezoidal channel studies: (1) Nusselt Numbers are larger for test configurations with higher rib height to hydraulic diameter (e/Dh) ratios. (2) Nusselt Numbers are lower for test configurations with smaller rib height to width (e/w) ratios. (3) At the range of local Reynolds Numbers from 20,000 to 30,000, the Nusselt Numbers for the orientation where the free end of turbulators are pointed towards the airfoil root are higher than the Nusselt Numbers of the orientation where the free end of turbulators pointed towards the airfoil tip. (c) To support the experimental results and trends, a CFD analysis modelling the test geometry can be completed.
机译：本文探讨了在涡轮机翼型冷却通道内使用湍流器的传热优势。在具有梯形，正方形和矩形横截面的纵横比分别为0.15、1、3的比例模型中测量局部和平均传热系数。还计算了通过方形和矩形通道的摩擦系数。为了模拟加热的壁边界条件，沿着测试部分放置了加热器。将液晶安装在加热器上方以测量温度。对于正方形和矩形的测试部分，壁在两个相对的侧面都进行了肋粗化处理，相邻壁上没有缠绕，也没有缠绕。对于梯形测试部分，墙壁的交错湍流器安装在两个相对的侧面上，并且在一侧带有薄膜排放孔。比较了高度与液压直径比（e / Dh）为0.09和0.14的湍流器配置；湍流器的高宽比（e / w）为0.45、0.63和0.73。这项研究得出结论后，发现：（a）基于方形和矩形通道研究的结果：（1）具有环绕结构会导致对所有通道壁的传热，并增加摩擦系数。 （2）随着流量从下游一区流向第五区，努塞尔特数增加。 （b）基于梯形通道研究的结果：（1）对于肋高与水力直径（e / Dh）之比较高的测试配置，努塞尔数更大。 （2）对于肋高与宽度（e / w）之比较小的测试配置，Nusselt数较低。 （3）在局部雷诺数从20,000到30,000的范围内，湍流器自由端指向翼型根的方向的努塞尔特数高于湍流器自由端指向的方向的努塞尔特数翼型尖端。 （c）为支持实验结果和趋势，可以完成对测试几何图形建模的CFD分析。

著录项

  • 作者

    Luo, Jackson.;

  • 作者单位

    Northeastern University.;

  • 授予单位 Northeastern University.;
  • 学科 Mechanical engineering.
  • 学位 M.S.
  • 年度 2016
  • 页码 271 p.
  • 总页数 271
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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