IMPROVEMENT OF THE BASIC CORRELATING EQUATIONS AND TRANSITION CRITERIA OF NATURAL CONVECTION HEAT TRANSFER
IMPROVEMENT OF THE BASIC CORRELATING EQUATIONS AND TRANSITION CRITERIA OF NATURAL CONVECTION HEAT TRANSFER
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DOI：
10.1002/htj.1018
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发表时间：
2001-06
期刊：
影响因子：
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通讯作者：
Shi-ming Yang
中科院分区：
文献类型：
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作者：
Shi-ming Yang
本文结合该领域的最新研究成果，从两个主要方面对自然对流换热的基本物理规律进行了改进。本文采用了一种优选的转换准则来关联所有的实验数据。由于过渡关联式主要是流动稳定性问题，因此Grashof数而不是Rayleigh数被发现是首选准则。此外，在水平圆柱体自然对流换热的情况下，最近获得了高瑞利数区的一系列实验数据。这些数据使建立新的可靠的相关性成为可能，也使检验以前的相关性的有效性成为可能。得出结论：以往水平圆柱体在高瑞利数区域的关联式是基于不可靠的实验结果。水平圆柱体的过渡关联出现在比先前建议的瑞利数高得多的值上。在竖板自然对流换热的情况下，现在可以获得加压条件下空气的更准确的物性值。这使得重新绘制桑德斯的可靠数据成为可能。根据这一结果和Warner和Arpaci的实验结果，推荐了一套新的层流、过渡区和湍流区自然对流换热的基本关联式。这些建议反映了对热对流领域基本物理规律的更好理解。©2001 Scripta Technica，热传输亚洲资源，30(4)：293-300,2001
In this paper, improvements in the basic physical laws of natural convection heat transfer were implemented in two major respects by incorporating recent research findings in this field. A preferred transition criterion was adopted in this paper to correlate all of the experimental data. Since transition correlations are primarily flow stability problems, the Grashof number, instead of the Rayleigh number, was found to be the preferred criterion. Furthermore, in the case of natural convection heat transfer from a horizontal cylinder, a series of experimental data in the high-Rayleigh-number regions recently became available. These data made it possible to establish new reliable correlations and also to test the validity of previous correlations. It is concluded that the previous correlation for a horizontal cylinder in high-Rayleigh-number regions was based on unreliable experimental results. The transition correlation for a horizontal cylinder occurred at much higher values of Rayleigh number than the previous recommendation. In the case of natural convection heat transfer from a vertical plate, more accurate property values for air under pressurized conditions are now available. This made it possible to replot the reliable data of Saunders. From this result and the experimental result of Warner and Arpaci, a new set of basic correlations in natural convection heat transfer for laminar, transitional, and turbulent regimes are recommended. These recommendations reflect a better understanding of the basic physical laws in the field of heat convection. © 2001 Scripta Technica, Heat Trans Asian Res, 30(4): 293–300, 2001