شبیه‌سازی عددی اثر اندازه و شکل نانوذرات Al2O3 در یک مبدل حرارتی دولوله‌ای

نوع مقاله : علمی ترویجی

نویسندگان

1 دانشگاه محقق اردبیلی

2 دانشگاه اردبیل

چکیده

در این پژوهش اثرات اندازه و شکل نانو ذرات  Al2O3معلق در سیال پایه‌ آب با کسر‌حجمی 2 درصد در دمای 25 درجه سانتیگراد روی عملکرد مبدل حرارتی دولوله‌ای به ‌صورت عددی در دو رژیم جریان آرام و آشفته مورد ‌بررسی قرار می گیرد. قطر نانو ذرات بین10 تا 100 نانومتر می‌باشد. نانو ذرات با اشکال کروی، استوانه‌ای و ترکیبی از نانو ذرات کروی-استوانه‌ای با درصدهای30، 50، 60، 70، 80، 90 از نانو ذرات استوانه‌ای مورد ‌مطالعه قرار گرفتند. اثر شکل نانو ذرات نشان داد با افزایش درصد نانو ذرات استوانه‌ای، میزان انتقال حرارت در مبدل حرارتی افزایش می یابد و نانو ذرات استوانه‌ای در رژیم جریان آشفته عملکرد بهتری در داخل مبدل حرارتی دارند بطوریکه عدد ناسلت آن4/15 درصد بیش‌تر از نانو سیالات حاوی نانو ذرات کروی می‌باشد. هم‌چنین مشاهده شد این سوسپانسیون بیش‌ترین میزان افت فشار را در داخل مبدل حرارتی دارد. نتایج اندازه نانو ذرات آلومینا با قطرهای 10، 50 و 100 نانومتر نشان داد که نانو ذرات با قطر کوچک‌تر بیش‎ترین افزایش عدد ناسلت و افت فشار را دارند.

کلیدواژه‌ها


عنوان مقاله [English]

Numerical Simulation of Effect of Size and Shape of Al2O3 Nanoparticles in a Double Tube Heat Exchanger

نویسندگان [English]

  • Alireza Miroliaei 1
  • Kobra Sadegh 2
2 University of Mohaghegh Ardabili
چکیده [English]

In this study, the effects of shape and size of Al2O3suspended nanoparticles in water-based fluid with 2%volume fraction at 25 °C are numerically investigated on the performance of double tube heat exchanger in the laminar and turbulent flow regimes. The nanoparticle’s diameter was considered between 10 and 100 nm. The nanoparticles with shapes of spherical, cylindrical, and combination of spherical-cylindrical with percentages of 30, 50, 60, 70, 80, 90 of cylindrical nanoparticles were studied. The effect of shape of nanoparticles showed that heat transfer rate increases in the heat exchanger by increasing the percentage of cylindrical nanoparticles and cylindrical nanoparticles offer better heat transfer characteristics and heat transfer rate in the turbulent flow regime as its Nusselt number is15.4% more than the spherical nanoparticles. It was also seen that this suspension has the maximum pressure drop in the heat exchanger. The results of size of alumina nanoparticles with diameters of 10, 50 and 100 nm showed that the nanoparticles with smaller diameter have the largest increase in Nusselt number as well as pressure drop.

کلیدواژه‌ها [English]

  • Combination of nanoparticles
  • Nanoparticle’s shape
  • Nanoparticle’s diameter
  • Double tube heat exchanger
  • nanofluid
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