کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
657125 1458055 2015 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Heterogeneous wetting surfaces with graphitic petal-decorated carbon nanotubes for enhanced flow boiling
ترجمه فارسی عنوان
سطوح خیس شدن ناهمگن با نانولوله های کربنی تزئینی گلبرگ گرافیتی برای افزایش جریان جوش
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
چکیده انگلیسی
Two-phase cooling is widely employed in temperature-sensitive devices for high heat flux dissipation owing to the benefits of latent heat exchange. The objective of this work is to elucidate the subcooled flow boiling characteristics of heterogeneous wetting surfaces using water as the working fluid. Heterogeneous wetting surfaces with alternating parallel stripes of superhydrophobic (SHo) and superhydrophilic (SHi) regions are fabricated with graphitic petal-decorated carbon nanotube (GPCNT) coatings. Graphitic petals are a carbon nanostructure comprising of stacks of graphene layers standing vertically on a substrate. GPCNTs are synthesized on bulk copper substrates by a two-step microwave plasma enhanced chemical vapor deposition technique. A combination of Teflon coating, shadow mask, and oxygen plasma treatment is utilized to create composite wetting surfaces with differing superhydrophilic area fractions and SHo to SHi channel width ratios. Boiling experiments reveal that heterogeneous wetting surfaces with higher superhydrophilic area fraction (0.66 and 0.85) exhibit significant reduction in surface superheat and higher heat transfer coefficients throughout the entire boiling regime as opposed to uniform SHo and SHi boiling surfaces. Flow visualization reveals enhanced active nucleation site density and preferential bubble nucleation in the superhydrophobic channels of composite wetting surfaces. Isolated near-spherical vapor morphologies on surfaces with higher superhydrophilic area fraction promote thin film evaporation and enhanced bubble ebullition cycles, thereby leading to improved two-phase thermal performance.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Heat and Mass Transfer - Volume 87, August 2015, Pages 380-389
نویسندگان
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