科研之友
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摘要
In this paper the most important literature data on polymer and surface-active additives effect on flow drag reduction and heat transfer effect in pipeline systems, as well as on liquid film flow characteristics, are presented. Previous published reviews by Gyr and Bewersdorff [1995], Choi [2000] and Graham [2004] were concerned with drag reduction effects in polymer solutions, and drag reduction effects in surfactant solutions were reviewed by Zakin et al. [1998]. The authors of the present review paper limited themselves to review important issues related to drag reduction effect and heat transfer in turbulent flows without phase change. Special attention was directed to elaborate the similarities and differences of drag reduction in high-molecular polymers and surfactants solutions, which relate to the flow phenomena and the associated heat transfer in straight tubes, coils and in failing films. It has been underlined that despite the large amount of research, which includes applications of modern measurement techniques to study turbulence phenomena and the rheological characteristics, the details of the drag reduction and heat transfer mechanisms are still not well understood. In the experimental studies performed in the last years with mixed drag reducers systems (polymer/surfactant, surfactant/surfactant), it has been shown that the presence of other surfactants or polymer in drag reducing surfactant systems causes an increase of the system stability and of the temperature range in which the additives are most effective. Perhaps the zwitterionic surfactants with special additives have the potential to become very useful in the future. It has been shown that another important issue for future research is finding drag reducing systems for long-distance transport of non-polar fluids, taking into account changeable environment temperature conditions.
- 出版日期2007
