Name: measurements of local instantaneous convective heat transfer in a pipe - single and two-phase flow
Uploaded: 2018-04-30T14:30:00
Description: Watch this Scientific Journal Video about Measurements of Local Instantaneous Convective Heat Transfer in a Pipe - Single and Two-phase Flow at JoVE.com

这项工作得到了以色列科学基金会281/14 号赠款的支持。

1. 瞬时温度测量试验段
<ol><li>测试部分的制造过程 (图 2)
	<ol>
<li>切一根管子的一段至少70厘米长。 注意:试验段的直径和壁厚应与实验装置中所用的管材相同。</li>
		<li>使用铣削机在测试部分沿管道切割4相邻的窄窗, 每个窗口的宽度为6毫米, 长80毫米, 连续窗口之间有25毫米的间隙。</li>
		<li>从12µm 薄不锈钢箔, 削减 40-60 cmlong 和12毫米...

<ol>
	<li>Hetsroni, G., Rozenblit, R., Yarin, L. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+hot-foil+infrared+technique+for+studying+the+temperature+field+of+a+wall.">A hot-foil infrared technique for studying the temperature field of a wall.</a> Meas. Sci. Tech. 7, 1418 (1996).</li><li>Babin, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Experimental investigation of the local heat transfer in gas-liquid slug flow. , (2015).</li><li>Babin, V., Shemer, L., Barnea, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Local+instantaneous+heat+transfer+around+a+raising+single+Taylor+bubble.">Local instantaneous heat transfer around a raising single Taylor bubble.</a> Int. J. Heat Mass Transfer. 89 (9), 884-893 (2015).</li><li>Fershtman, A., Shemer, L., Barnea, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Instantaneous+heat+transfer+rate+around+consecutive+Taylor+bubbles.">Instantaneous heat transfer rate around consecutive Taylor bubbles.</a> Int. J. Heat Mass Transfer. 95, 865-873 (2016).</li><li>Fershtman, A., Shemer, L., Barnea, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transient+convective+heat+transfer+in+a+pipe+due+to+impulsively+initiated+downward+flow+and/or+heat+flux.">Transient convective heat transfer in a pipe due to impulsively initiated downward flow and/or heat flux.</a> Int. J. Heat Mass Transf. 111, 1181-1191 (2017).</li><li>Hetsroni, G., Hu, B. G., Yi, B. G., Mosyak, A., Yarin, L. P., Ziskind, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heat+Transfer+in+Intermittent+Air-Water+Flow-Part+I:+Horizontal+Tube.">Heat Transfer in Intermittent Air-Water Flow-Part I: Horizontal Tube.</a> Int. J. Multiphase Flow. 24, 165 (1998).</li><li>Hetsroni, G., Hu, B. G., Yi, B. G., Mosyak, A., Yarin, L. P., Ziskind, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heat+Transfer+in+Intermittent+Air-Water+Flow-Part+II:+Upward+Inclined+Tube.">Heat Transfer in Intermittent Air-Water Flow-Part II: Upward Inclined Tube.</a> Int. J. Multiphase Flow. 24, 188 (1998).</li><li>Hetsroni, G., Mewes, D., Enke, C., Gurevich, M., Mosyak, A., Rozenblit, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heat+transfer+to+two-phase+flow+in+inclined+tubes.">Heat transfer to two-phase flow in inclined tubes.</a> Int. J. Multiphase Flow. 29, 173-194 (2003).</li><li>Ghajar, A. J., Tang, C. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heat+Transfer+Measurements,+Flow+pattern+maps+and+flow+visualization+for+non-boiling+two-phase+flow+in+horizontal+and+slightly+inclined+pipe.">Heat Transfer Measurements, Flow pattern maps and flow visualization for non-boiling two-phase flow in horizontal and slightly inclined pipe.</a> Heat Transfer Eng. 28, 525 (2007).</li><li>Franca, F. A., Banneart, A. C., Camargo, R. M. T., Goncalves, M. A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanistic+modelling+of+the+convective+heat+transfer+coefficient+in+gas-liquid+intermittent+flows.">Mechanistic modelling of the convective heat transfer coefficient in gas-liquid intermittent flows.</a> Heat Transfer Eng. 29, 984-998 (2008).</li><li>Kim, D., Ghajar, A. J., Dougherty, R. L., Ryali, V. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+20+two+phase+heat+transfer+correlations+with+seven+Sets+of+experimental+data,+including+flow+pattern+and+tube+inclination+effects.">Comparison of 20 two phase heat transfer correlations with seven Sets of experimental data, including flow pattern and tube inclination effects.</a> Heat Transfer Eng. 20, 15 (1999).</li><li>Nicklin, D. J., Wilkes, J. O., Davidson, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two-phase+flow+in+vertical+tubes.">Two-phase flow in vertical tubes.</a> Trans. Inst. Chem. Eng. 40, 61 (1962).</li><li>Donnelly, B., O'Reilly Meehan, R., Nolan, K., Murray, D. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+dynamics+of+sliding+air+bubbles+and+the+effects+on+surface+heat+transfer.">The dynamics of sliding air bubbles and the effects on surface heat transfer.</a> Int. J. Heat Mass Transfer. 91, 532-542 (2015).</li><li>Liu, T., Pan, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Infrared+thermography+measurement+of+two-phase+boiling+flow+heat+transfer+in+a+microchannel.">Infrared thermography measurement of two-phase boiling flow heat transfer in a microchannel.</a> Applied thermal engineering. 94, 568-578 (2016).</li><li>Dumitrescu, D. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stromung+an+einer+Luftblase+im+senkrechten+Rohr.">Stromung an einer Luftblase im senkrechten Rohr.</a> Z. Ang. Math. Mech. 23, 139 (1943).</li><li>Davies, R. M., Taylor, G. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+mechanics+of+large+bubbles+rising+through+extended+liquids+and+trough+liquid+in+tubes.">The mechanics of large bubbles rising through extended liquids and trough liquid in tubes.</a> Proc. R. Soc. London, Ser. A. 200, 375 (1949).</li></ol>

瞬态管流局部传热的实验研究是一项复杂的任务, 需要高端测量仪器和方法, 以及一个定制的实验设备, 特别是一个专门设计的测试部分。本协议显示了一种热成像技术, 它能够忠实地测量由于流动流体力学的变化而在壁温和传热速率上的快速时间变化。
详细介绍了测试部分的制造过程。该设施的关键步骤是用薄薄的不锈钢箔代替管道壁的一部分。箔由电流加热;它的内部边是?...

在过去的几十年中, 大量的对流换热实验研究, 使用不同的技术来测量墙体和/或流体温度的各种流动结构。影响非恒定过程温度测量精度的因素之一是传感器的响应速度慢。为了记录局部瞬时壁温, 测量设备的响应速度足够快, 而记录温度的表面必须与随时间变化的流量处于热平衡状态。因此, 表面的热惯性必须足够小。相关的时间尺度是由引起对流换热变化的水动力现象决定的。因此, 快速响应对于记录瞬态流中的时间依赖性温度至关重要。
为了满足这些要求, 红外摄像机用于记录一个特殊的自制造测试部分, 它允许对流程中的任何变化进行快速的温度响应。管子壁的一部分被切断, 用薄的不锈钢箔代替。Hetsroni et使用了类似的方法。1但是, 它们使用的箔太厚, 无法精确测量瞬时温度的变化, 只显示了时间平均温度。降低箔厚度大大提高了时间响应。2在实验室中应用此方法测量两相流3、4和单相管道流5中的瞬态现象的对流换热系数。
在图 1中给出了两相流设备的示意图布局, 在 Babin et . 中可以找到关于独特进气装置的附加信息。3
由于瞬态流动行为和孔隙率对管内截面的影响, 两相流中对流换热的研究非常复杂。因此, 许多研究只提出了一个给定流的平均对流换热系数作为特定流条件的函数6,7,8,9,10,11. 然而, 文件由唐纳利et 。12和刘et 。13表示两阶段局部对流换热研究的实例。
本研究讨论了在管道中注入停滞或流动液体的单个拉长 (泰勒) 气泡的传热测量。泰勒气泡以恒定的平移速度传播14,15,16。气泡传播速度的确定使用光学探针方法, 由激光光源和光电二极管3,4。
红外摄像机和光学探头的结合允许测量局部瞬时对流换热, 作为从泰勒气泡顶部或底部的距离的函数。
瞬时壁温可用于计算对流换热系数、 h和努塞尔数:
<img alt="Equation 1" src="/files/ftp_upload/57437/57437eq1.jpg">, (1)
其中q为箔的热流, tw 和T∞分别为壁温和入口水温, k为液体电导率, D为管径。通常用于确定传热系数的体积温度没有测量, 以避免对流量产生任何干扰。

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measurements of local instantaneous convective heat transfer in a pipe - single and two-phase flow

本手稿提供一步一步的描述的制造过程的测试部分设计, 以测量局部瞬时传热系数作为一个函数的液体流速在透明管道。通过某些修正, 该方法扩展到气液流动, 特别强调单拉长 (泰勒) 气泡对传热增强的影响。采用无创热成像技术测量了电加热金属箔的瞬时温度。箔被胶合在管子的一个狭窄的槽切开的盖子。箔的热惯量小到足以检测瞬时箔温度的变化。测试部分可以沿着管道移动, 足够长的时间覆盖不断增长的热边界层的相当一部分。
在每一个实验运行的开始, 得到一个恒定的水流速率和热通量到箔的稳定状态, 并作为参考。然后将泰勒气泡注入管道中。泰勒气泡通过垂直管内传播时的传热系数变化是测量点距离从运动泰勒气泡底部的函数。因此, 结果代表了局部传热系数。在相同条件下预制的多个独立运行允许积累足够的数据, 以计算在瞬态对流换热过程中可靠的集合平均结果。为了在与气泡一起移动的参考框架中执行此操作, 必须在任何时候都知道气泡沿管道的位置。本文详细描述了用光学探针测量泰勒气泡的长度和平移速度的方法。

在图 4中显示了一个光学传感器输出记录的示例, 其中一个泰勒气泡在充满积水的垂直管道中上升。最初的大下落代表电路的开头由于泰勒气泡尖, 而以后更短的下落跟随上升到最初的价值由于延长的气泡尾巴的通过, 代表在液体苏醒的分散的气泡在泰勒的泡沫后面。两个光学探针的输出之间的时间漂移是明显的, 这是由于两个探头沿管道之间的距离。...

Watch this Scientific Journal Video about Measurements of Local Instantaneous Convective Heat Transfer in a Pipe - Single and Two-phase Flow at JoVE.com

Measurements of Local Instantaneous Convective Heat Transfer in a Pipe - Single and Two-phase Flow

本文介绍了在单或两相管流中测量局部瞬时对流换热系数的方法。本文还提出了一种简单的光学方法来确定长 (泰勒) 气泡在恒定速度下运动的长度和传播速度。

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