Study on thermal and fluid flow characteristics in turbulent channel flows with multiple twisted tape vortex generators
Study on thermal and fluid flow characteristics in turbulent channel flows with multiple twisted tape vortex generators
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DOI：
10.1016/j.icheatmasstransfer.2010.02.004
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发表时间：
2010-07-01
影响因子：
7
通讯作者：
Eiamsa-ard, S.
中科院分区：
文献类型：
--
作者：
Eiamsa-ard, S.
本文研究了多扭带涡流发生器对矩形通道内传热和流体摩擦特性的影响。采用三种不同扭比（y/w = 2.5，3.0和3.5）的扭带在通道中产生不同的旋流和湍流强度。将扭带组装成三种不同自由间距比的MT-VG，S/W = 1.66（5条带），S/W = 1.25（7条带）和S/W = 1.0（9条带）。结果的雷诺数范围从2700到9000在恒定的普朗特数，Pr = 0.7，使用空气作为测试流体，进行检查。在研究范围内，与使用光滑通道相比，MT-VG通道的存在导致传热率增加约10.3%至169.5%。在相同的工况下，具有较小扭曲比（y/w）和自由间距比（s/w）的通道比具有较大扭曲比和自由间距比的通道具有更高的换热速率和压力损失。此外，还建立了努塞尔数（Nu）和摩擦因数（f）的关联式，并确定了在恒定泵浦功率下的热增强指数。(C)2010爱思唯尔有限公司版权所有。
This research has been performed to study the influences of multiple twisted tape vortex generators (MT-VG) on the heat transfer and fluid friction characteristics in a rectangular channel. The experiments conducted using the twisted tapes with three different twist ratios (y/w = 2.5, 3.0 and 3.5) for generating different swirl and turbulent intensities in the channel. The twisted tapes are assembled to obtained the MT-VG with three different free-spacing ratios, s/w = 1.66 (5 tapes), s/w = 1.25 (7 tapes) and s/w = 1.0 (9 tapes). The results for the Reynolds number ranged from 2700 to 9000 at constant Prandtl number, Pr = 0.7, using air as the test fluid, are examined. In the studied range, the presence of channel with MT-VG leads to increase in heat transfer rate over the use of smooth channel around 10.3 to 169.5%. The channel with the smaller twist ratio (y/w) and free-spacing ratio (s/w) provides higher heat transfer rate and pressure loss than those with the larger of twist ratio and free-spacing ratio under similar operation conditions. In addition, correlations of Nusselt number (Nu) and friction factor (f) have been developed and the thermal enhancement index at constant pumping power is also determined. (C) 2010 Elsevier Ltd. All rights reserved.