بررسی انتقال حرارت و جریان آرام نانوسیال از دیدگاه قانون دوم ترمودینامیک در یک مبدل حرارتی جریان مخالف

نویسندگان

دانشگاه سمنان

چکیده

در این مقاله با استفاده از حل عددی معادلات حاکم بر جریان سیال و انتقال حرارت آن، تأثیر افزودن کسر حجمی نانوذرات بر عملکرد یک مبدل حرارتی جریان مخالف از دیدگاه قانون دوم ترمودینامیک بررسی شده است. از مدل تکفاز برای مخلوط سیال پایه و نانوذرات استفاده شده است. برای محاسبه چگالی، ظرفیت گرمایی ویژهی نانوسیال، لزجت و ضریب رسانش از فرمول‌های تحلیلی و تجربی موجود استفاده شده است. برای حل عددی معادلات حاکم از روش حجم محدود (FVM) استفاده شده است. برای ارتباط بین میدان سرعت وفشار از الگوریتم سیمپل (SIMPLE) استفاده شده است. نتایج نشان می‌دهد که با اضافه کردن نانوذرات در قسمت حلقوی مبدل، آنتروپی تولید شدهی کل به میزان بسیار اندکی افزایش مییابد که قابل چشم پوشی است. با افزایش کسر حجمی نانوذرات ضریب انتقال حرارت (U ) و انتقال حرارت کل(Q) میزان قابل توجهی افزایش می‌یابد و همچنین نسبت بازگشت‌ناپذیری به گرمای مبادله شده (عدد آنتروپی (Ns)) کاهش خواهد یافت.

کلیدواژه‌ها


عنوان مقاله [English]

Second law analysis of nanofuid laminar flow in a counter-flow heat exchanger

نویسندگان [English]

  • Kamyar Kamani
  • Roohollah Rafee
چکیده [English]

In this paper the results of numerical simulations for heat transfer of a nanofluid flow inside a counter flow heat exchanger is presented. Effects of addition oftheAl2O3 nanoparticles on the entropy generation ofthesystem are investigated. Single fluid model is used for simulation of the nanofluid flow. Analytical and experimental formulations are used for density, specific heat, viscosity and conductivity of nanofluid. Finite volume method (FVM) has been used for numrerical simulation and SIMPLE algorithm is applied for pressure velocity coupling. It is found that adding nano particles in annulus, causes a little incerement in entropy generation which can be overlooked. On the other hand, the increasing of volume fraction of nanoparticles leads to ascend heat transfer coefficient (U ) and total heat transfer (Q) significantly, and it results in decreased entropy number (Ns).

کلیدواژه‌ها [English]

  • Heat Exchangers
  • Nanofluid
  • Entropy Generation Number
  • Laminar flow
 

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