Nanofluids are a new class of fluid in which nanometer sized particles are suspended in the base fluid. Adding nanoparticles to a conventional fluid improves its thermal conductivity by up to 250% relative to base fluid. It has high specific surface area, long term stability, less particle clogging, effective thermophysical properties like a future of heat transfer. It is able to handle the role as a smart fluid in multifield of Process Industry, Petrochemical industry, Solar thermal industry & Chemical reactors.
Nanofluids- From Vision to Reality by Anamika Sarkar.pdf
1.
2. 1. What are Nanofluids
2. Why use Nanofluids
3. Materials of Nanofluid
4. Types of Nanofluids
5. Synthesis of Nanofluid
6. Stability of Nanofluid
7. Nanofluid’s Thermophysical Properties
8. Thermal Conductivity of Nanofluid
9. Limitations & Challenges
10. Applications of Nanofluids
11. Indian Companies using Nanofluids
12. Conclusion & Future
3. 1
“ A Nanofluid is a engineered
colloidal suspensions of
Nanomaterials in a base fluid. ”
Nanofluid Colloids
= Base Fluids + Nanomaterials
4. 2
✓ Long term stability of nanoparticles dispersion
✓ High Specific Surface Area
6. 4
✓ Minimal particle clogging
✓ Adjustable Properties :
I. Surface wet ability
II. Thermal Conductivity
III. High single-phase
heat transfer coefficient
IV. Miniaturized system
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7. 5
Nanoparticle Materials:
1. Metals
2. Oxide Ceramics
3. Metal Carbides
4. Nitrides
5. Non-metals
6. Layered
Base Fluids:
1. Water
2. Coolants
3. Oil & other Lubricants
4. Bio-fluids
5. Polymer Solution
9. Mixing of Base fluid &
Dispersant
Adding Nanoparticles &
adjust pH value
Nanoparticles suspension by
Magnetic stirring &
Ultrasonic vibration
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A. Two-Step Method
Eastman et al. ,Wang and Xu , and Lee et al. adopted
this approach to form their Al2O3 Nanofluids.
10. Direct mixing of
Nanoparticles & Base fluid
Dispersant addition &
Ultrasonication
8
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B. Single Step Method
Developed by Akoh et al. and was named the
Vacuum Evaporation into a Running Oil Substrate
(VEROS) method.
11. 9
❑ Two opposing forces for
poor stability due to the
interaction between the
particles and base-fluid :
1. Van der Waals
attractive force
2. Electrical double-layer
repulsive force
15. 1. Brownian Motion 2. Interfacial Layer 3. Volume fraction of particles
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▪ Reasons to enhance the thermal conductivity of Nanofluids-
16. 14
▪ Effects of some parameters-
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i. Particle Volume Fraction
ii. Particle Size
iii. Particle Shape
iv. Particle Material
v. Base fluid
vi. Temperature
vii. Effect of Acidity (pH)
17. 15
❑ Lower Specific heat
❑ Disagreement between experimental data & theoretical model predictions
❑ Poor characterization of nano suspension
❑ Complex physical phenomena
❑ Increased Pressure drop
❑ Thermal performance in turbulent flow
❑ High cost of Nanofluids
18. 16
1) Heat Transfer Intensification
a) Electronic Applications
b) Transportation
c) Industrial Cooling Applications
d) Heating Buildings & Reducing
Pollution
e) Nuclear Systems Cooling
f) Space & Defence
19. 17
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2) Mass Transfer Enhancement
3) Energy Applications
a) Energy Storage
b) Solar Absorption
4) Mechanical Applications
a) Friction Reduction
b) Magnetic Sealing
20. 18
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5) Biomedical Applications
a) Antibacterial Activity
b) Nanodrug Delivery
Other Applications of Nanofluid as-
6) Intensify Microreactors
7) Vehicular Brake Fluids
8) Based Microbial Fuel Cell
9) Unique Optical Properties
23. 21
Many interesting exciting potential applications of Nanofluids have been
reported in the past decades. It can be considered as the future of heat transfer
applications. They are expected to give better thermal performance than
conventional fluids. The following key issues should receive greater attention in
coming future by further experimental & theoretical research on-
o Performance of Nanofluids
o Increase in Viscosity by the use of Nanofluids
o Shape of additives in Nanofluids
o Stability of the Suspension
o Thermal performance at high temperature
o Property dependence on the shape of additives
