本文以實驗及模擬方式在同心雙圓管下進行，探討流體在等熱通量中同心雙圓管內層流之強制對流中的熱傳遞特性與效益。先調製以超純水為基底與純20烷製成奈米乳液在不同濃度下並測量其熱性質，再調製以超純水為基底與氧化鋁奈米顆粒製成奈米流體並測量其熱性質，將外環流體以奈米乳液流動而內環流體以奈米流體流動，探討奈米乳液、奈米流體取代純水之效益。
實驗外管使用無氧紅銅管，內管使用不銹鋼管，外管外徑為6mm，外管內徑為5.4mm，長度為1250mm，而內管外經為4.6mm，內管內徑為4.2mm，加熱段長度為700mm。使用鎳鉻電阻線緊密纏繞加熱段外管壁，利用電源供應器使加熱段達等熱通量條件。
實驗中所設定的條件:加熱功率=70w、110w、150w與流量比 =0.17、0.30、0.45、0.70、1.0、1.6、2.38、4.00，和雷諾數Re,ST=500、1000、1500下之固定總流量，奈米乳液重量濃度4.88%、9.38%，奈米流體體積濃度0.5%。
實驗結果表明:平均熱傳增益在總流量277.49(cm3/min)流量比為0.45熱功率為110W時，內管純水而外環奈米乳液4.88%有22%增益、9.38%有29%增益，而外環奈米乳液4.88%內管奈米流體0.5%有24.4%增益。
數值模擬結果:純水在總流量181.84(cm3/min)流量比0.17、0.45、1.00、2.38下呈現熱阻關係，隨流量比越大同心雙圓管總熱阻越小，反之，流量比越小熱阻越大。

In this paper, experiments and simulations are carried out under concentric double circular tubes to explore the heat transfer characteristics and benefits of fluid in forced convection of laminar flow in concentric double circular tubes with equal heat flux. First, prepare a nanoemulsion with ultra-pure water as the base with pure n-eicosane at different concentrations and measure its thermal properties. Then, prepare a nanofluid with ultra-pure water as the base with alumina nanoparticles and measure its thermal properties. The outer ring fluid is flowed by nanoemulsion and the inner ring fluid is flowed by the nanofluid, to discuss the benefits of nanoemulsion and nanofluid instead of pure water.

The outer tube of the experiment is an oxygen-free copper tube, and the inner tube is a stainless steel tube. The outer diameter of the outer tube is 6mm, the inner diameter of the tube is 5.4mm, and the length is 1250mm. The outer tube of the inner wall is 4.6mm and the inner tube of the inner wall is 4.2mm. The length of the heating section is 700mm. Use nickel-chromium resistance wire to tightly wrap the outer tube wall of the heating section, and use the power supply to make the heating section reach equal heat flux conditions.

The conditions set in the experiment: heating power = 70w, 110w, 150w and flow rate ratio = 0.17, 0.30, 0.45, 0.70, 1.0, 1.6, 2.38, 4.00, and total flow under Reynolds number =500、1000、1500, Nano emulsion weight concentration 4.88%、9.38% and alumina nanofluid volume concentration 0.5%.

The experimental results show that the average heat transfer efficacy compared with pure water when the total flow rate is 277.49(cm3/min), the flow ratio is 0.45 and the heat power is 110W, the inner tube of pure water and the outer ring of nanoemulsion weight concentration 4.88% have 22% efficacy and weight concentration 9.38% have 29%. The outer ring nanoemulsion 4.88% inner tube nano fluid volume concentration 0.5% has a 24.4% efficacy.

Numerical simulation results: pure water shows a thermal resistance relationship at flow ratios of 0.17, 0.45, 1.00, and 2.38. When the larger the flow ratio, the smaller the total thermal resistance of the concentric double circular tube. On the contrary, the smaller the flow ratio, the greater the thermal resistance.

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