Papers by Keyword: Al₂O₃ Nanofluid

Abstract: Knowledge of fluid rheology and flow characteristics is important when studying nanofluid flow in porous media. In this study, an experimental investigation is presented to determine the nanofluid viscosity, the permeability and the inertial (non-Darcy) parameter of a porous cylinder made of several capillary tubes. The applicability of the Darcy-Forchheimer equation for power-law fluids to estimate pressure drop through the porous material is discussed. The occurrence of particle losses from the base fluid (deposition) is also verified.Experiments are completed in two steps. In the first step, physical properties of nanofluids consisting of deionized water and different volume concentrations of Al₂O₃ nanoparticles is measured. In the second step, Al₂O₃-deionized water nanofluids are pumped through a porous cylinder (porosity 0.249) to evaluate hydraulic and intrinsic permeabilities, and the inertial parameter. The effect of Al₂O₃ volume fraction on these flow properties is studied, and the void morphology changes within the porous cylinder via deposition of nanoparticles are analyzed.

Abstract: The source of fossil fuel is decreasing. The price increased rapidly. Population and demand of energy increased significantly over the years. Carbon pollution and global warming are becoming major issues. The best way to overcome this problem is by changing to renewable source of energy. One of it is solar thermal energy. However, a solar technology is currently still expensive, low in efficiency and takes up a lot of space. Nanofluid is recognized as a solution to overcome this problem. Due to the high thermal conductivity of nanofluids, the thermal efficiency of a solar collector can be increased and thus decreasing the size of the system. This paper analyzes the efficiency of using the Al₂O₃ nanofluid as absorbing medium in flat-plate solar collector and estimated the potential of size reduction. When applying the same output temperature of Al₂O₃ nanofluid as with water, it can be observed that the collectors size can be reduced up to 24% of its original size.

Abstract: The purpose of this paper is to research and develop a new nanofluid synthesis system that uses plasma arc as heat source to fabricate nanofluid having high suspension stability. This system uses high temperature produced by plasma arc system to cause transient vaporization to metal, which is then followed by the induction of vaporized metallic gas into the collection piping by the induction system. At the same time, it mixes thoroughly with the pre-condensed deionized water, and the mixture is then underwent a rapid cooling process. Because of low temperature, the metallic gas condenses into nanoparticles, which is finally stored in the collection tank in the form of nanofluid. This paper discusses the influence of working current towards the fabricated Al2O3 nanoparticle. Also, based on the Al2O3nanofluid having different pH values, it analyzes into the suspension stability of its Zeta potential value. Furthermore, it investigates into the absorption properties of Al2O3 nanofluid towards UV/Vis. Besides, as known from the experimental result of the fuel calorific test, when the weight concentration of the Al2O3 nanofluids that is produced by a better fabrication is 3%, it explores into its good combustion efficiency towards 92 unleaded gas.