Variation of Forced Convective Heat Transfer in Rectangular Duct Flow of a Magnetic Fluid under Magnetic Field
Variation of Forced Convective Heat Transfer in Rectangular Duct Flow of a Magnetic Fluid under Magnetic Field
复制标题
磁场作用下磁流体矩形管流强制对流传热的变化
DOI：
10.1088/1742-6596/412/1/012025
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
T. Sawada and Y. Kawaguchi
中科院分区：
文献类型：
--
作者：
M. Motozawa;T. Sekine;T. Sawada and Y. Kawaguchi
实验研究了磁场作用下磁流体矩形管内流动的强制对流换热特性。进行了改变磁场强度的实验，并且该磁场可以从0 mT变化到600 mT。基于水力直径的雷诺数被设定为960、1900（层流）和2830（湍流）。实验结果表明，在磁性流体层流的情况下，当磁场施加到磁性流体流时，在磁场存在的区域中，热传递局部增加。相反，在磁性流体的湍流中，热传递不是增强而是减少。为了更好地理解这种传热现象，我们用超声速度剖面法（UVP）测量了磁流体流动的速度分布。结果表明，在层流情况下，矩形通道中心流速减小，近壁区流速梯度增大。通过测量压力梯度，计算了磁场作用下的流动阻力，并讨论了流动阻力与传热的关系。
Variation of forced convective heat transfer in a rectangular duct flow of a magnetic fluid under a magnetic field was investigated experimentally. Experiments were performed changing the magnetic field intensity, and this magnetic field could be varied from 0 mT to 600 mT. The Reynolds number based on the hydraulic diameter was set to 960, 1900 (laminar flow), and 2830 (turbulent flow). The results of the experiments show that in the case of laminar flow of the magnetic fluid, when a magnetic field is applied to a magnetic fluid flow, heat transfer locally increases in the region where the magnetic field exists. In contrast, in the turbulent flow of the magnetic fluid, heat transfer is not enhanced but reduced. In order to better understand this heat transfer phenomenon, we measured the velocity distribution of magnetic fluid flow by the Ultrasonic Velocity Profile (UVP) method. In the case of laminar flow, the result shows that the flow velocity at the center of the rectangular duct decreases and the velocity gradient in the near-wall region increases. Moreover, we calculated the flow resistance under a magnetic field by measurement of the pressure gradient, and the relationship between heat transfer and flow resistance was discussed.