Heat transfer characteristic of nanoparticles dispersed in
inorganic base fluid
Mohamed Aslam bin Mohamed Iqbal
22431195
Supervisor: Dr Hung Yew Mun1
Outline
• Introduction
• Problem Statement
• Objectives
• Literature Review
• Methodology
• Results and Discussion
• Conclusion2
Nanoparticles• Particles sized between 1nm – 100nm
• Can be synthesis in many ways eg., miling method.
• Common nanoparticles are aluminum oxide, zinc oxide, copper oxide
• This experiment : silver oxide
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Base fluids
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• Can be categorized as organic and inorganic
• Common base fluids used in heat transfer application eg., ethylene glycol, oil (organic)
• Inorganic base fluids eg., water
• This experiment : sodium chloride
Nanofluids
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• Nanoparticles dispersed in base fluids form nanofluids
• 2 type of preparation :
I. One-step method
ii. Two-step method
• This experiment : two-step method
Problem Statement
• No general equation can predict the nanofluids heat transfer characteristic.
• Lack of research on nanofluids using inorganic base fluids besides water.
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Objectives
• To determine thermal conductivities, viscosity, and pH of nanofluids.
• To investigate the effect of temperatures and volume fractions on thermal conductivity and viscosity.
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Literature Review
• Effect of volume fraction thermal conductivity
• Effect of temperature on thermal conductivity
• Effect of volume fraction on viscosity
• Effect of temperature on thermal conductivity 9
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Effect of volume fraction on thermal conductivity
• Thermal conductivity increase with volume fraction
Study by Ali et al. (Al2O3/water)
Study by Aklilu and Abraham (Al2O3/water)
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Effect of temperature on thermal conductivity
Study by Seok and Choi (Cu/Water)
• Thermal conductivity increase with temperature
Study by Cherng et al. (Al2O3/Water)
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Effect of volume fraction on viscosity
• Viscosity increase with volume fraction
Study by Weerapun and Somchai (TiO2/Water)
Study by Madhusree and Dey (Al2O3/Water)
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Effect of temperature on viscosity
• Viscosity decrease as temperature increase
Study by Jessica and Rebecca (Al2O3/Water)
Study by Teng et al. (Al2O3/Water)
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Sample preparationa) Base fluid
Calculate amount of sodium chloride needed to prepare 1 litre of 1 mol
Disperse the in deionized water Place on magnetic stirrer for 1 minutes.
b) Nanoparticles
Decide 5 volume fraction (0.05%,0.1%,0.2%,0.3%,0.5%)
Calculate amount needed
• Pour the sodium chloride solutioninto a 120ml beaker
• Add nanopartiles into base fluid
• Cover with aluminum foil
• Place in sound enclosure and sonicate.
• Sonication (QSONICA Q700):5 hours, Amplitude 20. 16
Experiment
Results and discussion
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• Effect of temperature and volume fraction on thermal conductivity
• Enhancement of thermal conductivity
• Effect of temperature and volume fraction on viscosity
• pH of different volume fraction at different temperature
Effect of temperature and volume fraction on thermal conductivity
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• From graph:Volume fraction increase, thermal conductivity increase
Temperature increase, thermal conductivity increase
• Increase probably is due to the increase of Brownian motion
Enhancement of thermal conductivity
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• From graph:
Highest enhancement of nanofluids of 192.3% is observed at temperature 61.13 degree celcius using 0.5% volume fraction.
• Overall silver nanofluids display good thermal properties
Effect of volume fraction and temperature on viscosity
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• From graph:Volume fraction increase, viscosity increaseTemperature increase, decrease
• Viscosity is a measure of molecular attraction
• Temperature increase, molecular attraction decrease.
• Volume fraction increase, molecular attraction increase.
pH of different volume fraction at different temperature
• There is a slight increase of pH with increase of temperature and slight decrease of pH with increase of volume fraction
• pH is close to 7 so the nanofluids formed is neutral
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Conclusion
• Increase in temperature will increase the thermal conductivity of nanofluids, reduce the viscosity of nanofluids and there is only slight increase in pH nanofluids.
• Increase in volume fraction will increase the thermal conductivity of nanofluids, increase viscosity of nanofluids and reduce pH of nanofluids.
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