نوع مقاله: مقاله پژوهشی
نویسندگان
پژوهشکده‌ی کاربرد پرتوها، پژوهشگاه علوم و فنون هسته‌ای، سازمان انرژی اتمی
چکیده
استفاده از نانو سیال‌ها برای افزایش حاشیه‌ی ایمنی سیستم‌های حرارتی با شار حرارتی بالا مانند نیروگاه‌های هسته‌ای، از طریق بالا بردن شار حرارت بحرانی (CHF) اخیراً مورد توجه بسیاری از پژوهش‌گران قرار گرفته است. در این پژوهش، آزمایش جوشش استخری نانو سیال‌های 2SiO، 2TiO، 3O2Al در غلظت‌های مختلف با استفاده از سیم نیکل- کرم به قطر mm 0.2 در فشار اتمسفری انجام گرفت. مقایسه‌ی شار حرارت بحرانی نانو سیال‌ها نشان داد که در نانو سیال SiO2 با افزایش غلظت به میزان 0.05% وزنی، شار حرارت بحرانی نسبت به آب خالص به میزان قابل توجهی (56%) افزایش می‌یابد. تصاویر میکروسکوپی بعد از آزمایش نشان داد که در فرایند جوشش استخری، پوششی از نانوذرات SiO2 بر روی سیم ایجاد می‌شود. همچنین نتایج آزمایش آب خالص و سیم‌های پوشش داده شده با نانوذرات در غلظت‌های مختلف از SiO2، نشان داد که علت اصلی افزایش شار حرارت بحرانی نانو سیال می‌تواند تغییرات میکروساختاری باشد که به وسیله‌ی پوشش نانوذرات SiO2 بر روی سطح سیم تشکیل می‌شوند.
کلیدواژه‌ها
عنوان مقاله [English]
Experimental Studies on CHF Characteristics of Nanofluids at Pool Boiling
نویسندگان [English]
- H Kazeminejad
- A Akhavan
- H Khalafi
- E Ataeivarjovi
چکیده [English]
The use of nanofluids to increase the safety margin of high heat flux thermal systems in nuclear power plants through the enhancement of the critical heat flux (CHF) has been considered recently by researchers. To investigate the CHF characteristics of nanofluids, pool boiling experiments of nanofluids with various concentrations of TiO2, Al2O3 and SiO2 nanoparticles were carried out using a 0.2 mm diameter cylindrical Ni–Cr wire under the atmospheric pressure. The results showed that the CHF of SiO2 nanofluid is significantly enhanced by 56% compared with that of pure water by increasing the nanoparticle concentration to 0.05 wt%. Microscopic images, subsequent to the CHF experiment of SiO2 nanofluid, revealed that nanoparticles are deposited on the wire surface during the pool boiling of the nanofluid. The CHF of pure water was measured on a nanoparticle-coated wire which was produced during the pool boiling experiments of SiO2 nanofluids. The results of these experiments showed clearly that the main reason for the CHF enhancement of the nanofluid is the modification of the heating surface by the SiO2 nanoparticle deposition during the pool boiling.
کلیدواژه‌ها [English]
- Nanofluids
- Critical Heat Flux
- Pool Boiling
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