تحلیل جریان سیال غیر نیوتنی در مبدلهای قاب و صفحه‌ای به کمک دینامیک سیالات محاسباتی

نوع مقاله: مقاله پژوهشی

چکیده

امروزه مبدلهای صفحه‌ای برای گرم و سرد کردن جریان‌های مختلف کاربرد زیادی در صنایع شیمیایی، غذایی و دارویی دارند. چون بسیاری از سیالات استفاده شده در این صنایع خواص رئولوژیکی غیر نیوتنی دارند، در این تحقیق به کمک دینامیک سیالات محاسباتی یا CFD دو بعدی، رفتار جریان محلول کربوکسی متیل سلولز (CMC) در غلظت‌های وزنی 5/0 تا 2 درصد، به عنوان سیال غیر نیوتنی پاورلا در محدوده رینولدز 10 تا 300 و دمای ثابت (20 درجه سانتیگراد)، در زوایای مختلف شورون مبدلهای صفحه‌ای تحلیل شده است. برای ایجاد هندسه و شبکه‌بندی، حل معادلات حاکم با روش حجم محدود و تحلیل دینامیکی نتایج به‌ترتیب از نرم‌افزارهای Gambit ،FLUENT و Techplot استفاده شده است. در نهایت روابط عدد رینولدز و ضریب اصطکاک تعیین و تأثیر زاویه شورون و پارامترهای رئولوژیکی بر ضریب اصطکاک و رژیم جریان بررسی شده است. نتایج حاصل از محاسبات CFD با اطلاعات تجربی مقایسه و همخوانی خوبی بین آنها دیده شد.
 

کلیدواژه‌ها


عنوان مقاله [English]

Non_Newtonian Fluid Flow Analysis Using CFD in Plate and Frame Heat Exchangers

چکیده [English]

Due to their high thermal effectiveness, good flow distribution and ease of sanitation, plate heat exchangers (PHEs) are widely used for continuous pasteurization of liquid food products. Since most food products in this research are non-Newtonian fluids, flow behavior in various chevron angles of non–Newtonian power law  fluids is studied by means of 2D Computational Fluid Dynamics (CFD). For this purpose, aqueous solutions of carboxy-methyl-cellulose (CMC) at different weight concentrations, ranging from 0.5 % to 2% and 10≤Reg≤300 held at a constant temperature of 20oC were considered as operating conditions. To generate geometry and mesh, solve governing equations by finite volume method and analyze CFD results, software applications Gambit 2.0 and FLUENT 6.0.12 were used respectively. Analyses over the relationship between Reynolds number, fanning friction factor and rheological parameters of the fluid and chevron angles of the plates for different      concentrations of CMC have been performed. Predictions of CFD calculations were compared to the experimental data, and these results showed a very good agreement.
 

کلیدواژه‌ها [English]

  • Plate Heat Exchangers
  • CFD
  • Power-Law Fluid
  • Friction factor

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