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化工学报  2015 

热线外低Rayleigh数自然对流换热的机理

DOI: 10.11949/j.issn.0438-1157.20150010, PP. 2420-2425

Keywords: 自然对流,尺度效应,低Rayleigh数,微尺度,振动热线

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Abstract:

采用铂丝自测流体温度的实验方法,利用50×10-6m2·s-1硅油对低Rayleigh数下水平与竖直热线外自然对流传热的机理进行了研究,对比实验测得的实验数据和Tsubouchi、Fand的实验数据发现,实验结果与Tsubouchi的拟合曲线吻合度较高,低Ra下水平热线外的Nu高于竖直热线,但均远高于数值模拟的预测值。为了解释该现象,进行了低振动Re下的自然对流数值模拟,发现在低于某一振动Re下,Nu将与Re无关,但此时Nu与实验测的Nu基本一致,与Tsubouchi的数据偏差也在5%以内,说明微尺度铂丝外自然对流可能存在振动的作用机理。

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