Heat transfer enhancement using Al2O3–water nanofluid for an electronic liquid cooling system
ABSTRACT We have experimentally investigated the behaviour and heat transfer enhancement of a particular nanofluid, Al2O3 nanoparticle–water mixture, flowing inside a closed system that is destined for cooling of microprocessors or other electronic components. Experimental data, obtained for turbulent flow regime, have clearly shown that the inclusion of nanoparticles into distilled water has produced a considerable enhancement of the cooling block convective heat transfer coefficient. For a particular nanofluid with 6.8% particle volume concentration, heat transfer coefficient has been found to increase as much as 40% compared to that of the base fluid. It has also been found that an increase of particle concentration has produced a clear decrease of the heated component temperature. Experimental data have clearly shown that nanofluid with 36 nm particle diameter provides higher heat transfer coefficients than the ones of nanofluid with 47 nm particle size.
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ABSTRACT: Experimental works were conducted to investigate the effect of Al2O3 sizes and volume concentration on the rate of nanofluids heat transfer in a compact heat exchanger. Two sizes of Al2O3 nanoparticle, 40 nm and 100 nm, were mixed with demineralized water at 2% and 10% volume concentrations. Sodium Lauryl Sulphate (SLS) powder was added to enhance the mixing process and stabilize the dispersion of the nanofluids. A custom-made closed loop test rig were designed, fabricated and tested for these experiments. The test rig was set-up to represent the actual application of the nanofluids in cooling of a compact heat exchanger. Experimental runs were conducted which include the runs for water, 40 nm Al2O3 -water and 100 nm Al2O3 -water. The results indicate that Al2O3 -water gave better heat transfer performance than water alone. Nanofluids with 40 nm-Al2O3 gives better heat transfer performance as compared to 100 nm-Al2O3 nanofluids. The results of the current work generally indicate that nanofluids have the potential to enhance the heat transfer of a compact heat exchanger if properly designed. This superior performance of the nanofluids would only be produced if smaller diameter of nanoparticles were used (less than 100 nm). No enhancement in heat transfer can be observed by using nanofluids with particle size of 100 nm or at higher volume loading (more than 5%).Applied Mechanics and Materials 12/2013; 465:622.
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ABSTRACT: a b s t r a c t In this study, fluid flow of the Al 2 O 3 nanofluid in a horizontal double pipe heat exchanger fitted with mod-ified twisted tapes were experimentally studied under turbulent flow conditions. The experiments with different geometrical progression ratio (GPR) of twists as the new modified twisted tapes and different nanofluid concentration were performed under similar operation condition. Pitch length of the proposed twisted tapes and consequently the twist ratios changed along the twists with respect to the geometrical progression ratio (GPR) whether reducer (RGPR < 1) or increaser (IGPR > 1). Regarding the experimental data, utilization of RGPR twists together with nanofluids tends to increase heat transfer and friction factor by 12% to 52% and 5% to 28% as compared with the tube with typical twisted tapes (GPR = 1) and nano-fluid. Contrarily, performances were weakened by using for IGPR twists 0.6 to 0.92 and 0.75 to 0.95. The thermal performances of the heat exchanger with nanofluid and modified twisted tapes were evaluated for the assessment of overall improvement in thermal behavior. Generalized correlations were developed for the estimation of Nusselt number, friction factor and thermal performance factor under turbulent flow conditions. Satisfactory agreement between the present correlations and obtained experimental data validate the proposed correlations.International Journal of Heat and Mass Transfer 11/2014; · 2.52 Impact Factor
Dataset: Enhanced HT by interfacing etc