Post on 28-Oct-2014
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A Study and Experimental observations
CH2040-Mechanical Operations
Nanofluids
Department of Chemical Engineering CH2040-Mechanical Operations
Nano Crusaders
-Neha Nathan CH10B042
-Sake Karthik CH10B055
-Mohammed Rhazy CH10B100
-Shivani Patel CH10B101
What are nanofluids?
Nanofluids is a name used to
describe a fluid consisting of
solid nanoparticles with size
less than 100nm suspended on
it with solid volume fractions
typically less than 4%.
Examples :
• Blood (Natural nanofluid)
• CuO nanoparticles in glycol
Department of Chemical Engineering CH2040-Mechanical Operations
Why do we need nanofluids?
• Enhance thermal properties like heat transfer
and thermal conductivity, when compared to the
host fluid.
• Size does matter!
unique transport properties:
do not settle under gravity and do not block flow
Department of Chemical Engineering CH2040-Mechanical Operations
What gives Nanofluids the edge?
Effect of
Nanoparticle
Interfacial Layer
This enhances the
thermal conductivity!
Department of Chemical Engineering CH2040-Mechanical Operations
(M.Reza Azizian- Thermo physical
properties of Nanofluids)
Department of Chemical Engineering CH2040-Mechanical Operations
CuO Nanowires
Preparation
And
Trends
Department of Chemical Engineering CH2040-Mechanical Operations
SYNTHESIS OF CuO NANOWIRES
• Copper nano-particles are placed in 1 N HCL for one minute.
• Rinse with water thoroughly and finally clean with ethanol.
• Place the samples in a ceramic crucible inside a furnace. The
temperature inside the furnace rises at a rate of around 10 °C/min.
Thermal oxidation can be performed at 400 - 600 °C for 3 - 6 hr.
• Once the holding time is over, slowly reduce the temperature down
to room temperature.
• A thin film with a thickness of about 10 μm splits off from the copper
substrate.
• The film surface is black and fluffy, indicating the formation of dense
CuO nanowires.
Department of Chemical Engineering CH2040-Mechanical Operations
SEM TEST ON CuO OBTAINED
• The sample was supposed to be prepared at a temperature of 600 °C, however, at
the end of a holding time of 6 hrs, the tubular furnace unexpectedly displayed a
temperature of 198 °C.
• SEM analysis was performed:
• SEM analysis on this sample revealed that CuO nanowires were not formed. The
images obtained :
Department of Chemical Engineering CH2040-Mechanical Operations
TRENDS (CITED FROM LITERATURE)
Effect Of Evaporation Temperature on the Growth
Effect of Evaporation Time on the Growth
At 600 °C, the effect of
evaporation time on the growth
was noted.
At six different temperatures, the
trends in growth of nanowires are
as follows:
Temperature Dimensions of CuO
Rods
300°C Diameter : 40 nm
Length: 1 μm
400°C Diameter : 100 nm
500°C Diameter : 80 nm
600°C Diameter : 70 nm
700°C Diameter : 120 nm
800°C Diameter : 150 nm
900°C No nanowires observed
Evaporation Time Length of CuO
rods
0.5 h 5 μm
2 h 10 μm
10 h 20 μm
20 h 35 μm
Department of Chemical Engineering CH2040-Mechanical Operations
Preparation of large-scale cupric oxide nanowires by thermal
evaporation method
L.S. Huanga, S.G. Yanga,*, T. Lia, B.X. Gua, Y.W. Dua, Y.N. Lub, S.Z. Shib
SEM IMAGES FOR THE TRENDS SEM images of CuO nanowires prepared
at various temperatures: (a) 300 C, (b)
400 C, (c) 500 C, (d) 600 C, (e) 750 C and
(f) 800 C.
Morphologies of CuO nanowires
prepared at 600°C for different times:
(a) 0.5 h, (b) 2 h,(c) 10 h and (d) 20 h.
Department of Chemical Engineering CH2040-Mechanical Operations
Preparation of large-scale cupric oxide nanowires by thermal
evaporation method
L.S. Huanga, S.G. Yanga,*, T. Lia, B.X. Gua, Y.W. Dua, Y.N. Lub, S.Z. Shib
Stability Test-CuO nanofluid
• Prepared a 0.05, 0.15 and 0.25
volume % CuO suspension in
de-ionized water.
• Solutions were checked every
4 hours for a week.
• RESULT: The nanoparticles
did not settle. They were still in
the solution phase. CuO
nanofluid is stable
Department of Chemical Engineering CH2040-Mechanical Operations
Photograph taken
after leaving the vial
with 0.05% CuO
suspension in de-
ionozed water for 4
hours
Density Test – CuO
nanoparticles
13 g of 10 % by weight
CuO suspension
x=0 x = 0.025 x = 0.05 x = 0.075 x = 0.1
Department of Chemical Engineering CH2040-Mechanical Operations
Using a densitometer, the density of each
of the 5 samples was measured.
Batch Mass Fraction
of CuO
Density (g/cc) 1/ρ (g/cc)-1
1 0 0.99814 1.001874
2 0.025 1.00344 0.980132
3 0.05 1.01405 0.961291
4 0.075 1.02341 0.938749
5 0.1 1.02912 0.916708
Department of Chemical Engineering CH2040-Mechanical Operations
Density Calculations
1/ ρx=0 = 1/ρsolvent
1/ρx=1 = 1/ρp
1/ρp – 1/ρsolvent = (1/ρx=0.1 - 1/ρx=0)/0.1
= -0.85166 (g/cc)-1
The graph gives 1/ρsolvent = 1.001874 (g/cc)-1
1/ρp = 0.150214 (g/cc)-1
Therefore, the density of CuO particles is calculated to be
6.66g/cc
Department of Chemical Engineering CH2040-Mechanical Operations
Inference
• The calculated density of
CuO = 6.66g/cc
• The theoretical density of
CuO = 6.31g/cc
• Therefore, the values are
nearly correct and the
substance taken is CuO
Densitometer
Department of Chemical Engineering CH2040-Mechanical Operations
Thermal Conductivity of Nanofluids
Department of Chemical Engineering CH2040-Mechanical Operations
Review and Comparison of Nanofluid Thermal Conductivity and Heat Transfer Enhancements
Wenhua Yu a , David M. France b , Jules L. Routbort a & Stephen U. S. Choi b c
Factors affecting thermal
conductivity of nanofluids
1) Particle volume concentration
2) Particle materials
3) Particle size
4) Particle shape
5) Base fluid material
6) Temperature
7) Additive
8) Acidity
Department of Chemical Engineering CH2040-Mechanical Operations
Measurement of Thermal
Conductivity
• Dual needle line heat source method
• Transient method or non steady state heat
conduction.
• Measurements done during the process of
heating up.
• Advantage-less experimentation time
• Disadvantage-data analysis
Department of Chemical Engineering CH2040-Mechanical Operations
DNL Device
Department of Chemical Engineering CH2040-Mechanical Operations
Experimentation Setup Sample
• The primary probe - a
line heater and a
thermocouple
• Secondary probe -
thermocouple only.
• Analysis to be done until
both the probes
temperature reading
becomes same.
• We are more concerned
with the variation of
temperature with time of
primary probe.
Primary
probe
Secondary
probe
DNL Device probes
Department of Chemical Engineering CH2040-Mechanical Operations
Calculations
• Thermal conductivity (kW/m◦C) of the medium may be obtained as
k = q/4π S (1)
• where q is heat input (W/m)
• S is a slope determined by linear regression of measured temperatures against the natural logarithm of time (◦C).
Evaluation of Thermal Properties of Food Materials at High Pressures Using a Dual-Needle Line-Heat-Source Method
S. ZHU, H. S. RAMASWAMY, M. MARCOTTE, C. CHEN, Y. SHAO, AND A. LE BAIL
Department of Chemical Engineering CH2040-Mechanical Operations
Calculations-What we got
30
31
32
33
34
35
36
37
3.25 3.3 3.35 3.4 3.45 3.5
Temperature v/s log time
Primaryprobe
Linear(Primaryprobe)
Log time
Tem
per
atu
re
0
5
10
15
20
25
30
35
40
45
50
0 50 100
Tte
mp
erat
ure
(.C
)
Time (sec)
Temperature vs Time
Primary probe
Secondary probe
Department of Chemical Engineering CH2040-Mechanical Operations
Results-Thermal conductivity SI no Volume fraction Slope Thermal Conductivity (W/
m0C)
1 0 0.97925 0.276736
2 0.05 0.882 0.30717
3 0.15 0.7831 0.34592
4 0.25 0.39 0.694607
0
0.5
1
1.5
2
2.5
3
0 0.1 0.2 0.3
k/ko v/s volume fraction
CuO sample
Volume fraction
k/ko
Department of Chemical Engineering CH2040-Mechanical Operations
References
Department of Chemical Engineering CH2040-Mechanical Operations
Preparation of large-scale cupric oxide nanowires by thermal
evaporation method
L.S. Huanga, S.G. Yanga,*, T. Lia, B.X. Gua, Y.W. Dua, Y.N. Lub, S.Z.
Shib
Evaluation of Thermal Properties of Food Materials at High Pressures
Using a Dual-Needle Line-Heat-Source Method
S. ZHU, H. S. RAMASWAMY, M. MARCOTTE, C. CHEN, Y. SHAO,
AND A. LE BAIL
Review and Comparison of Nanofluid Thermal Conductivity and Heat
Transfer Enhancements
Wenhua Yu a , David M. France b , Jules L. Routbort a & Stephen U.
S. Choi b c
Acknowledgements
Department of Chemical Engineering CH2040-Mechanical Operations
Polymer Lab
• Santhosh
• Ashok
• Venkat
• Gaurav
• Kalpana
• Swami
• Shyam
Last but not the least
Metallurgical Department
• Phani Kumar sir
• Kaushalya
Dr Basavaraja M Gurrappa
Kanan Sir’s URP team
• Deepthi M
• Saranya