Surfactants and fluid properties

被引:30
作者
Beutler, A
Greiter, I
Wagner, A
Hoffmann, L
Schreier, S
Alefeld, G
机构
[1] Physik-Department, Institut E 19, TU München
来源
INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID | 1996年 / 19卷 / 05期
关键词
refrigerating system; absorption; water/lithium bromide; surface tension; performance;
D O I
10.1016/S0140-7007(96)00034-5
中图分类号
O414.1 [热力学];
学科分类号
摘要
Investigations were made to clarify if the change in the surface tension and the viscosity of aqueous solution of LiBr due to small amounts of surfactants can explain the observed enhancement of the heat-transfer coefficient in a falling film absorber with horizontal tubes. It is expected that, especially for this type of absorber, the surface tension has an impact on the absorber performance. Yet it will be shown in this study that the effect of the reduced surface tension alone cannot explain the changed heat-transfer behavior for all investigated surfactants. This also applies to the viscosity. Measurements of this quantity which will be presented show that the decrease of the viscosity is too small to be responsible for the enhancement. Effects creating turbulence, such as Marangoni convection, or the drop characteristics have to be taken into account. Further investigations, particularly of the surface tension, are necessary to understand the mechanism of enhancement due to surfactants. Copyright (C) 1996 Elsevier Science Ltd and IIR
引用
收藏
页码:342 / 346
页数:5
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