کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
653507 1457506 2013 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Experimental investigation of the thermophysical properties of AL2O3-nanofluid and its effect on a flat plate solar collector
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
Experimental investigation of the thermophysical properties of AL2O3-nanofluid and its effect on a flat plate solar collector
چکیده انگلیسی

Experimental investigations have been carried out for obtaining the thermophysical properties of 60:40 (by mass) ethylene glycol/water mixture and water based alumina nanofluids. The effect of density and viscosity on the pumping power for flat plate solar collector has been investigated as well. Nanofluids of 0.05–0.1%v/v concentrations were prepared and characterized. Water based alumina nanofluids were found more preferable against sedimentation and aggregation than ethylene glycol/water mixture based nanofluids. The measured thermal conductivities of both types of the nanofluids increased almost linearly with concentration and are consistent in their overall trend with previous works done at lower concentrations by different researchers. In contrast to thermal conductivity, viscosity measurements showed that the viscosity of the Al2O3–water nanofluids exponentially decreases with increasing temperature. Furthermore, the measured viscosities of the Al2O3–water nanofluids showed a non-linear relation with concentration even in the low volume concentration except 0.05%v/v at below 40 °C. On the other hand, Al2O3–EG/water mixture exhibited Newtonian behavior. Existence of a critical temperature was observed beyond which the particle suspension properties altered drastically, which in turn triggered a hysteresis phenomenon. The hysteresis phenomenon on viscosity measurement, which is believed to be the first observed for EG/water-based nanofluids, has raised serious concerns regarding the use of nanofluids for heat transfer enhancement purposes. Results suggest that nanofluids can be used as a working medium with a negligible effect of enhanced viscosity and/or density. Results also show that the pressure drop and pumping power of the nanofluid flows are very close to that of the base liquid for low volume concentration.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Communications in Heat and Mass Transfer - Volume 48, November 2013, Pages 99–107
نویسندگان
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