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Optimum Design of Heat Exchanger for the Air Conditioning System with Surfactant Drag Reduction Technique

表面活性剂减阻技术空调系统换热器优化设计

基本信息

批准号：
12555216
负责人：
USUI Hiromoto
金额：
$ 8.38万
依托单位：
Kobe University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12555216/
关键词：
Energy Saving Drag Reduction Surfactant District Heating and Cooling Air Conditioning Turbulence Control 抵抗低減技術空調伝熱流体輸送

项目摘要

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.

本研究对表面活性剂分子结构与传热降低的关系进行了基础研究。这是从化学方面提出的避免换热器传热降低的适当技术。由于阳离子表面活性剂与反离子的组合使用可以有效地降低阻力，因此选择了四种阳离子表面活性剂来讨论分子结构的影响。这些是油基三甲基氯化铵、油基羟乙基二甲基氯化铵、油基双羟乙基甲基氯化铵、油基三羟乙基氯化铵。这些表面活性剂具有不同的亲水基团，这导致了不同的胶束结构形成和胶束结构破裂行为。本研究得出的结论意见概述如下。(1)减阻效果强烈地依赖于机械破坏胶束的重新形成速率。(2)当羟乙基基团的数目从0增加到2时，大的减阻效果的可用温度范围向低的方向移动。但具有三个羟乙基的表面活性剂即使在较低的温度范围内也几乎没有表现出减阻。这可能是由于羟乙基基团的大亲水头延迟胶束重组。(3)油基双羟乙基甲基氯化铵是一种性能优良的减阻表面活性剂，但从减热的角度来看，该表面活性剂韧性太强，胶束再形成速度太快。因此，我们提出，具有三个羟乙基的表面活性剂，油烯基三羟乙基氯化铵，作为表面活性剂减阻体系的实际应用的最佳候选人。目前，该表面活性剂已在实际空调系统中进行了减阻效果评价。