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首页> 外文期刊>Journal of Heat Transfer >Enhancement of Heat Transfer Behind Sliding Bubbles
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Enhancement of Heat Transfer Behind Sliding Bubbles

机译：增强滑动气泡后的传热

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摘要

The time-dependent temperature distribution on an inclined, thin-foil uniform-heat-generation heater was used to infer the heat transfer enhancement caused by the passage of an FC-87 bubble sliding beneath the lower surface of the heater. A two-camera system was used: One camera recorded color images of a liquid crystal layer applied to the upper (dry) side of the heater while a second camera simultaneously recorded the position, size, and shape of the bubble from below. The temperature response of the heater could then be correlated directly to the bubble characteristics at any given time during its passage. The data along the line bisecting the bubble wake from the nine bubbles comprising 54 bubble images were analyzed. The heat transfer in the wake behind the sliding cap-shaped bubbles is very effective compared with the natural convection that occurs before the passage of the bubble. The maximum values of heat transfer coefficient in the range of 2500 W/m~2 K were produced in very sharply peaked curves. The point of maximum cooling measured as a fraction of the local driving temperature difference before the bubble passage was identified and correlated with some success to the stream-wise length of the bubble. The location of the maximum heat transfer coefficient was reasonably correlated with bubble width. The level of the maximum heat transfer coefficient when cast as a Nusselt number based on bubble width grew to a saturation value as the bubble moved across the plate. A constant value of Nusselt number requires that the heat transfer coefficient falls as the bubble grows past some critical bubble size. This behavior was observed for the larger cap-shaped bubbles.
机译：使用倾斜的，薄箔均匀发热的加热器上随时间变化的温度分布来推断由于在加热器下表面下方滑动的FC-87气泡通过而引起的传热增强。使用了两个摄像头系统：一个摄像头记录了施加在加热器上侧（干燥）侧的液晶层的彩色图像，而另一个摄像头则同时从下方记录了气泡的位置，大小和形状。加热器的温度响应然后可以在其通过期间的任何给定时间直接与气泡特性相关。分析了沿着将包括54个气泡图像的9个气泡对分的气泡唤醒线的数据。与在气泡通过之前发生的自然对流相比，滑动帽形气泡后面的尾流中的热传递非常有效。传热系数的最大值在2500 W / m〜2 K的范围内以非常尖锐的峰值曲线产生。在确定气泡通过之前，将最大冷却点测量为局部驱动温度差的一部分，并将其与气泡沿流的长度的成功程度相关联。最大传热系数的位置与气泡宽度合理相关。当气泡基于板块宽度移动为Nusselt值时，最大传热系数的水平随着气泡在板上的移动而增加到饱和值。恒定的努塞尔数值要求传热系数随着气泡的增长超过某个临界气泡大小而下降。对于较大的帽形气泡观察到了这种行为。

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  • 来源
    《Journal of Heat Transfer》 |2009年第12期|121005.1-121005.9|共9页
  • 作者

    D. Keith Hollingsworth; Larry C. Witte; Marcelino Figueroa;

  • 作者单位

    Department of Mechanical Engineering,University of Houston,Houston, TX 77204-4006;

    Department of Mechanical Engineering,University of Houston,Houston, TX 77204-4006;

    Department of Mechanical Engineering,University of Houston,Houston, TX 77204-4006;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    sliding bubbles; enhancement; wakes;

    机译：滑动气泡;增强唤醒;

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