INFLUENCE OF THE PRANDTL NUMBER ON HEAT TRANSFER AT LIQUID FILM FLOWS DOWN SMOOTH AND ROUGH SURFACES

被引:0
作者
Magrakvelidze, T. [1 ]
Gigineishvili, G. [1 ]
Mikashavidze, A. [1 ]
Koberidze, T. [1 ]
Lomidze, Kh. [1 ]
机构
[1] Georgian Tech Univ, 77 M Kostava St, Tbilisi 0160, Georgia
来源
8TH THERMAL AND FLUIDS ENGINEERING CONFERENCE | 2023年
基金
美国国家科学基金会;
关键词
Heat transfer enhancement; Two-dimensional roughness; Vertical tube; Liquid film; Prandtl number; Critical Reynolds number; Laminar flow; Turbulent flow;
D O I
10.1615/TFEC2023.eap.045749
中图分类号
O414.1 [热力学];
学科分类号
摘要
The article presents the results of an experimental study on the effect of two-dimensional roughness and Influence of the Prandtl number (Pr) on heat transfer when a liquid film flows down a vertical surface. The following coolants were used in the experiments: network water, distilled water and ethyl alcohol. The experiments were carried out in the range of the Prandtl number (Pr) from 3 to 19, the Reynolds number (Re) varied from 100 to 45000. The experimental results obtained for a smooth surface are in good agreement with the existing literature data. As a result of the study, it was found that the creation of a two-dimensional roughness on the heat-transfer surface causes a significant increase in the intensity of heat transfer. At the same time, the degree of intensity of heat transfer increases noticeably with an increase in the Prandtl number. It has also been established that the two-dimensional roughness has a great influence on the critical value of the Reynolds number - Re-cr. In this case, the value of Recr for rough surfaces depends to a large extent on the Prandtl number. The obtained results indicate that the use of the method of artificial roughness to heat transfer enhancement in the corresponding heat transfer installations will lead to a significant increase in the efficiency of such installations.
引用
收藏
页码:657 / 663
页数:7
相关论文
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