engleski

Cooling characteristics of water based nanofluid with agitation

Series of quenching experiments were performed according to ISO 9950 and ASTM D 6482 standard. Water based nanofluids with 0.01, 0.1 and 0.2 g/l TiO2 were prepared using twostep method and ultrasonic homogenization. The nanofluids are tested to see the possibility of their application as high temperature heat transfer fluids. Nanoparticles used in this series of experiments were 50 nm in diameter. All of the cooling curves were recorded and analyzed using IVF SmartQuench system. The first set of experiments was conducted under still conditions according to ISO 9950 standard. Pure water and nanofluids were investigated. The addition of nanoparticles shows effect on full film phase duration, increase in maximum cooling rate and change in transition temperature. Second series of experiments are conducted according to ASTM D 6482 standard. For this purpose, quenching bath with agitation was built at the QRC. Three levels of agitation were tested - one according to the standard, 1000 rpm, and one below and one above the specified speed. Experiments with pure water and all three nanofluids were conducted and cooling curves recorded. Besides the cooling curve analysis using IVF software, statistical analysis of influence factors was done. The analysed influence factors were nanoparticle concentration and impeller rotational speed. The effects of agitation and nanoparticles contents on cooling characteristics were compared.

quenching; nanofluid; nanoparticles

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