مطالعه عدد‌ی انتقال حرارت مخلوط آب/ مواد تغییرفاز دهنده احاطه شده با نانوذرات داخل حفره حاوی استوانه چرخان

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده مهندسی مکانیک، دانشگاه صنعتی

چکیده

در مقاله‌ی حاضر انتقال حرارت داخل حفره‌ای حاوی مخلوط آب/ مواد تغییرفاز دهنده احاطه شده با نانوذرات مورد بررسی قرار گرفته است. دیواره‌های سمت چپ و راست به ترتیب گرم و سرد بوده و دیواره‌های افقی آدیاباتیک فرض شده است. یک استوانه‌ی چرخان دایروی در مرکز حفره قرار دارد که به صورت ساعتگرد و یا پادساعتگرد می‌تواند چرخش نماید. معادلات اساسی حاکم به فرم بی‌بعد از قبیل: پیوستگی، بقاء مومنتوم و بقاء انرژی با استفاده از روش المان محدود و به صورت کوپل با یکدیگر حل شده‌اند. جهت بررسی صحت نتایج عددی، مقایسه‌ای با خروجی‌های دیگران ارائه شده است که نشانگر تطابق بسیار خوب نتایج می‌باشد. پارامترهای مورد بررسی در این مطالعه عبارتند از: شعاع بی‌بعد استوانه(R)، عدد رایلی(Ra)، دمای ذوب بی‌بعد ماده تغییر فاز دهنده(θfu)، عدد استفان(St) و سرعت زاویه‌ای بی‌بعد استوانه چرخان(Ω). طبق نتایج بدست آمده با افزایش شعاع بی‌بعد استوانه از0/1=R تا 0/4= Rو با 300-= Ω نرخ انتقال حرارت 23/37 درصد افزایش می‌یابد. از طرف دیگر، در صورت عدم چرخش استوانه و با 4/0R=، نرخ انتقال حرارت نسبت به حفره‌ی فاقد استوانه، حدود 59/7 درصد کاهش می‌یابد. که نشان دهنده‌ی اهمیت چرخش استوانه داخل حفره در افزایش نرخ انتقال حرارت می‌باشد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Numerical Investigation of Heat Transfer of Water/Nano-Encapsulated Phase Change Materials in a Cavity Including a Rotating Cylinder

نویسندگان [English]

  • Farrokh Mobadersani
  • Negin Rashidi
صنعتی ارومیه-مهندسی مکانیک
چکیده [English]

In the present paper, heat transfer in a cavity containing a mixture of water + phase change materials surrounded by nanoparticles is investigated. The left and right walls are fixed at hot and cold temperatures, respectively, and horizontal walls are assumed to be adiabatic. There is a circular rotating cylinder in the center of the hole that can rotate clockwise or counterclockwise. The problem is considered two dimensional and fundamental governing equations such as continuity, momentum, and energy are solved in a coupled manner utilizing the finite element method (FEM). To check the accuracy of the numerical results, a comparison with the outputs of others is provided, which indicates a very good agreement of the results. The parameters studied in this study are: dimensionless radius of the cylinder (R), Rayleigh number (Ra), dimensionless melting temperature of the phase change material (θfu), Stephan number (St) and dimensionless angular velocity of the rotating cylinder (Ω). By increasing the dimensionless radius of the cylinder from R = 0.1 to R = 0.4 Ω = -300, the heat transfer rate enhances by 23.37%. On the other hand, with R = 0.4 and considering no-rotation case, the heat transfer rate will decrease by about 59.7% compared to the cavity without the cylinder. Which indicates the importance of rotation of the cylinder inside the cavity in the heat transfer rate enhancement.

کلیدواژه‌ها [English]

  • Nano-encapsulated phase change materials
  • Rotating cylinder
  • Natural convection
  • Finite element method

مراجع

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نشریه مهندسی مکانیک امیرکبیر
دوره 54، شماره 9
آذر 1401
صفحه 2175-2194

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