بررسی عملکرد انتقال حرارت جریان دو فازی نانوسیال در یک کلکتور خورشیدی سهموی با جاذب خارج از مرکز و عایق جامد
محورهای موضوعی : یافته های نوین کاربردی و محاسباتی در سیستم های مکانیکی
مجتبی جمعیتی
1
(گروه فیزیک، واحد نراق، دانشگاه آزاد اسلامی، نراق، ایران،)
حسین پورمحمدیان
2
(گروه مکانیک ، واحد نراق، دانشگاه آزاد اسلامی، نراق، ایران،)
کلید واژه: تشعشع, کلکتور خورشیدی سهموی خطی, بهینه‌سازی انرژی, نانوسیال, عایق جامد,
چکیده مقاله :
در این مطالعه تحلیل میدان جریان و انتقال حرارت جریان دو فازی نانوسیال در یک کلکتور خورشیدی سهموی با جاذب خارج از مرکز و عایق جامد مورد بررسی قرار گرفته است. سیال مورد استفاده در این کلکتور نانوسیال آب- آلومینیم است. هدف اصلی پژوهش پیش رو، بررسی تأثیر استفاده از سیستم جاذب خارج از مرکز و عایق جامد بر بازده انرژی کلکتورهای سهموی خطی است. بدین منظور بازده انرژی برای حالت‌های مختلف (شامل دمای محیط، دمای ورودی سیال، کسر حجمی نانوسیال، قطر نانوذرات و مشخصات هندسی) اندازه‌گیری و ارائه شده‌اند. مطالعه در رژیم جریان آشفته بوده و به منظور مدل سازی آن از مدل توربولانسی k−ε استفاده شده است. به منظور حل معادلات بقا از روش حجم محدود و الگوریتم SIMPLE C استفاده شده است. مدل‌های بهینه مختلف از نظر دارا بودن بیشترین بازده انرژی، معرفی شده و در نهایت براساس نتایج به دست آمده برترین مدل مشخص می‌شود. بر اساس نتایج بدست آمده بیشترین مقدار بازده انرژی در رینولدزهای مختلف، مربوط به کلکتور نوین و مدل دوفازی می‌شود. در جایگاه‌های بعدی به‌ترتیب، کلکتور نوین و مدل تک‌فازی، کلکتور پایه و مدل دوفازی و در انتها کلکتور پایه و مدل تک‌فازی قرار دارند. همچنین مشخص شد که با افزایش مقدار عدد رینولدز، تمامی حالات روند صعودی دارند. بیشینه مقدار بازده انرژی برای کلکتور نوین و مدل دوفازی در رینولدز 15000 بوده که مقدار آن برابر برابر 68٪ است. همچنین بیشینه مقدار بازده انرژی برای خروج از مرکز mm 20 در رینولدز 15000 بوده که مقدار آن برابر 9/74٪ است.
In this study, the flow field analysis and heat transfer of two-phase nanofluid flow in a parabolic solar collector with eccentric absorber and solid insulation have been investigated. The fluid used in this collector is nanofluid of water - Aluminium. The main aim of current study is to investigate the effect of using eccentric absorber system and solid insulation on the energy efficiency of linear parabolic collectors. For this purpose, energy efficiency has been measured and presented for different states (including ambient temperature, fluid inlet temperature, nanofluid volume fraction, nanoparticle diameter and geometric characteristics). The study is in turbulent flow regime and in order to model it, the k epsilon turbulence model has been used. In order to solve the survival equations, the finite volume method and the SIMPLE C algorithm have been used. Different optimal models are introduced in terms of having the highest energy efficiency, and the best model is determined. Based on obtained results, the highest energy efficiency in different Reynolds is related to the novel collector and two-phase model(TPM). In the next positions, respectively, are the novel collector and single-phase model(SPM), the basic collector and two-phase model, and at the end, the basic collector and single-phase model. It was also found that as the Reynolds number increases, all modes have an uptrend. The maximum amount of energy efficiency was for the novel collector and the two-phase model at Reynolds 15000, Which is equal to 68%. Also, the maximum energy efficiency for eccentricity 20 mm at Reynolds 15000, which is equal to 74.9%.
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