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

Introduction

• Nanoparticles

• Base fluids

• Nanofluids

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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)

Methodology

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Sample preparation

Experiment

Data Collection

Data Analysis

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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

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Data collection• KD2PRO – Thermal conductivity

• Vibro viscometer - viscosity

• pH meter - pH

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Data analysis

• Tabulate data

• Plot graph

• Conclude the trend of result

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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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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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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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

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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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The end

THANK YOU

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Questions and Answers

(Q&A)

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