نویسندگان

1 دانشکده مهندسی مکانیک، واحد شاهرود، دانشگاه آزاد اسلامی، شاهرود

2 باشگاه پژوهشگران جوان و نخبگان، واحد شاهرود، دانشگاه آزاد اسلامی، شاهرود

3 دانشکده ریاضی، دانشگاه صنعتی شاهرود، شاهرود

4 دانشکده ریاضی، واحد یاسوج، دانشگاه آزاد اسلامی، یاسوج

چکیده

در این تحقیق، دمای بی‌بعد و تولید آنتروپی در جریان سکون شعاعی نانوسیال تراکم‌ناپذیر روی استوانه نامحدود درحالت پایا بررسی شده است. جریان آزاد نیز پایا بوده و قدرت اولیه جریان K    است. حل تشابهی معادلات ناویر استوکس و معادله انرژی دراین مساله ارائه شده است. این معادلات، با استفاده از تبدیلات مناسبی که در این تحقیق معرفی شده است ساده‌سازی شده‌اند. معادلات کاملا تشابهی در شرایطی حل شده‌اند که دیواره استوانه تحت تاثیر شار حرارتی ثابتی قرار دارد. کلیه حل‌های فوق برای محدوده اعداد رینولدز  Re=ka^2/2vf بین 0/1تا 1000 و مقادیرمعینی ازکسر حجمی نانوذرات ارائه شده است که در آن    a شعاع استوانه است و  vf   لزجت سینماتیکی سیال پایه است. نتایج نشان می­دهند برای اعداد رینولدز بررسی شده، با افزایش کسر حجمی نانوذرات، عمق نفوذ مؤلفه محوری میدان سرعت کاهش می‌یابد درحالی که عدد ناسلت افزایش می­یابد همچنین بیشترین مقدار آنتروپی تولیدی محاسبه شده است.
 

کلیدواژه‌ها

عنوان مقاله [English]

Investigation of Entropy Generation in Stagnation Point Flow of Nano Fluid Impinging on the Cylinder with Constant Wall Heat Flux

نویسندگان [English]

  • H. Mohammadiun 1
  • M. Mohammadiun 1
  • M. H. Dibaee Bonab 1
  • M. Darabi 2
  • S. R. Hejazi 3
  • V. Janipour Bidsardareh 4

چکیده [English]

: In this research, dimensionless temperature and entropy generation for the steady state flow in the stagnation point of incompressible nanofluid impinging on an infinite cylinder have been investigated. The impinging free stream is steady with a constant strain rate  k. Similarity solution of the Navier-Stokes equations and energy equation is derived in this problem. A reduction of these equations is obtained using appropriate transformations introduced in this research. The general self similar solution is obtained when the heat flux on the cylinder wall is constant. All solutions brought above are presented for Reynolds numbers  Re=ka^2/2vf that range from 0.1 to 1000 and the selected values of particle fractions, where a is the radius of the cylinder and υf  is the kinematic viscosity of the base fluid. Results show that for Reynolds numbers examined, as the particle fraction increases, the depth of diffusion of the fluid velocity field in axial direction decreases, whereas Nusselt number is raised. Also, the maximum value of entropy generation has been calculated.

کلیدواژه‌ها [English]

  • Nanofluid
  • Stagnation point flow
  • Similarity solution
  • Volume fraction
  • Entropy generation
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