2002 Fiscal Year Final Research Report Summary
Optimum Design of Heat Exchanger for the Air Conditioning System with Surfactant Drag Reduction Technique
| Project/Area Number |
12555216
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
化学工学一般
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| Research Institution | Kobe University |
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Principal Investigator |
USUI Hiromoto Kobe University, Faculty of Engineering, Professor, 工学部, 教授 (20107725)
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| Co-Investigator(Kenkyū-buntansha) |
SUGAWARA Hitoshi Lion Co., Central Research Center, Chief Researcher, 研究開発本部, 主任研究員
SUZUKI Hiroshi Kobe University, Graduate School of Science and Technology, Associate Professor, 自然科学研究科, 助教授 (90206524)
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| Project Period (FY) |
2000 – 2002
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| Keywords | Energy Saving / Drag Reduction / Surfactant / District Heating and Cooling / Air Conditioning / Turbulence Control |
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| Research Abstract |
Basic research on the relationship between heat transfer reduction and surfactant molecular structure has been conducted in this study. This is the approach from chemical aspect to give an appropriate technique to avoid the hear transfer reduction at heat exchanger. Since the combined use of cationic surfactants with counter ion gives effective drag reduction, four cationic surfactants were selected to discuss the effect of molecular structure. These are oleyl tri-methyl ammonium chloride, oleyl hydroxyethyl di-methyl ammonium chloride, oleyl bis-hydroxyethyl methyl ammonium chloride, oleyl tri-hydroxyethyl ammonium chloride. These surfactants have different hydrophilic group, and this causes different behavior of micelle structure formation and micelle structure breakup. The concluding remarks obtained in this study are summarized as follows.
(1) The drag-reducing effect depends strongly on the re-formation rate of micelles disrupted mechanically.
(2) When increasing the number of hydroxyethyl groups from 0 to 2, the available temperature range of large drag reduction effect is shifted lower. But the surfactant having three hydroxyethyl groups barely exhibits the drag reduction even at the lower temperature range. This may be caused by the delayed micelle reformation by the large hydrophilic head of hydroxyethyl groups.
(3) The well-known drag-reducing surfactant, oleyl bis-hydroxyethyl methyl ammonium chloride, is confirmed to be exactly excellent one, but from the view point of heat transfer reduction, this surfactant is too tough and the micelle re-formation is too rapid. Thus, we propose that the surfactant having three hydroxyethyl groups, oleyl tri-hydroxyethyl ammonium chloride, as an optimum candidate for the practical application of surfactant drag reduction system. This surfactant is now under the evaluation in practical air-conditioning system with surfactant drag reduction.
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