In this presentation related about natural convective heat transfer incresed by using different nano particles. in this fluid is called nanofluids. Nanofluids improve the heat transfer rate of base fluid.

1. NATURAL CONVECTIVE HEAT
TRANSFER BY Al2O3 &PbO
NANOFLUIDS
GUIDED BY: Mr.S.SANKARA KUMAR. M.E
SUBMITTED BY:
P.MANIKANDAN
S.KRISHNAN
M.ALAGAPPAPANDIAN
G.BALA SINGH

2. INTRODUCTION
• Heat transfers are used in many industrial area.
• Natural Convective Heat Transfer by Nano Fluids
is nothing but exchange of thermal energy and
heat between the physical system by nano fluids.
• Convective heat transfer is the transfer of heat by
movement of fluids.
• Nano fluids, a name conceived by Dr.Choi , in
Argonne National Laboratory, to describe a fluid
consisting of solid nano particles with size less
than 100nm suspended on it with solid volume
fractions typically less than 4%.

3. OBJECTIVES
• To improve the heat transfer rate of base fluid
by adding nano particles.
• To determine the heat transfer coefficient of
natural convection of nanofluids in a tube.
• Water/oil has been chosen as base fluid.
• By varying volume concentration of nanofluid,
various thermal conductivity rate can be obtain.
• In addition, Al2o3 nano particles are stable in
various PH value.

4. SYNTHESIS METHODOLOGY
• THREE DIFFERENT STEPS FOR SYNTHESIS OF
NANOFLUIDS:
• By mixing of nano powder directly in
base fluid.
• By acid treatment of base fluid.
• By adding surfactants (surface active
agent) to the base fluid.

5. General preparation for nanofluids
All the above methods followed by
magnetic stirring with sonic process
about 2hours

6. DIRECT MIXING METHOD
 Directly mixing nano powder with base fluid.
 This method followed by magnetic stirring.
 It causes poor suspension stability.
 Nano powder settle down due to gravity .
 Particle settlement depends upon type of
nano powder used.
 This method is more suitable for oxide nano
particles (e.g. Al2O3, CUO, PbO ,etc. . , )

7. ACID TREATMENT OF BASE FLUID
By decreasing ph value by adding
suitable acid with base fluid.
By this method nano fluid with uniform
particle dispersion can be obtain.
But, causes corrosion to pipe wall.

8. ADDING SURFACTANTS TO THE BASE
FLUID
In this method a small amount of suitable
surfactant, generally 1/10 of mass of nano
powder is added to base fluid.
Some surfactants are ethylene oxide, soap,
natural oil, etc . . ,
It gives stable suspension with uniform
particle dispersion
Suspension state for long time without settling
down can obtain.

9. • Volume Concentration:
The volume concentration for nanofluid is
calculated by (Φ)
(wnp/ρnp)
Φ=
(wnp/ρnp)+(wbf/ρbf)
Wnp-weight of nano particle(kg)
ρnp-density of nano particle(kg/m3)
wbf-weight of base fluid(liters)
ρbf- ρnp-density of base fluid(kg/m3)

10. SAMPLE CALCULATION FOR
PREPARATION
• The weight of nano particle required for
preparation of 100ml cuo nanofluid of a
particular volume concentration, using water
as base fluid is calculated by formula .
(wcuo/6300)
Φ=
(wcuo/6300)+(100/1000)

11. Volume concentration (Φ)
(%)
Wcuo
(g) [for 100ml]
0.1 0.60872
0.2 1.21865
0.3 1.82981
0.4 2.44228
0.5 3.05582
0.6 3.6706
0.7 4.28676
0.8 4.90409
By changing the volume concentration thermal conductivity rate
can be obtain

12. SYNTHETIC PROCESS
Selection of nano particle and base fluid (al2o3/pbo & water/oil)
Preparation of nanofluid by any one of above method
Conducting experiment by varying volume concentration (Φ) & note down the
readings
Determine the heat transfer coefficient of nanofluid and traditional fluid
Comparison of heat transfer coefficient between nanofluid and traditional fluid is
done

13. LITERATURE SURVEY
• Many researches are carried out to improve the heat
transfer rate of base fluids using nano fluids.
• VisineeTrisakri shows the use of additives is a
technique applied to enhance the heat transfer
performance of base fluids. Recently as an innovative
material, nanometer-sized particles have been used
in suspension in conventional heat transfer fluids.
The suspended metallic or nonmetallic nanoparticles
change the transport properties and heat transfer
characteristics of base fluid.

14. • (Li et al., 2009). A 40% increase in thermal conductivity
was found in the Cu oil-based nanofluids with 0.3%
volume concentration.
• (Eastman et al., 1997).The Al2O3 water-based nanofluids
exhibited a 29% enhancement of thermal conductivity
for the 5% volume concentration nanofluids.
• Pak andCho studied the heat transfer performance of
Al2O3 and TiO2nano particles suspended in water and
expressed that convective heat transfer coefficient is 12%
smaller than that of pure water at 3% volume fraction.

15. • Heris et al investigated laminar flow of cuo/water
al2o3/water nanofluid through copper tube it results
heat transfer coefficient increases with increasing
volume concentration.
• Yang et al ,investigate convective heat transfer of
graphite nanofluid in copper tube . Inexpertly it
result heat transfer coefficient increases and thermal
conductivity decreases . the reasons is the size of
particle is average diameter of 1-2ᶣm and thickness
2-3nm . Apart from thermal conductivity particle
shape is an important factor.

16. RELATED TO OUR PROJECT
• Natural convective heat transfer investigation
was done by Putra et al & Wen and Ding has
found that it decreases in overall heat transfer
coefficient due to deterioration increases with
particle concentrations .
• This will overcome by changing the base fluid
or preparation method.

17. • Nano particle – Al2O3 & Pbo
• Base fluid – water/oil
• Volume concentration – 0.5 to 0.8%
• Method of preparation ;
1. acid treatment.
2. Adding surfactants.

18. EXPERMENTATION
• Initially Nanofluids are prepared and stored in storage
tank.
• Now it allow to pass through pipes.
• At the pipe connected with copper tube heater and
thermocouples.
• The heater is switched on it tends to produced the heat
it measure by thermocouple.
• When the nanofluid reaches the heater it absorbs heat
from the heater.
• The thermocouple measure the absorbing heat of
nanofluid from heater.

19. • The thermocouple is measured heat in copper
tube heater and inlet/outlet heat of nanofluid.
• The temperature are noted down in a tabular
column.
• The above steps are followed to traditional
fluid

20. SYSTEMATIC LAYOUT

21. JOURNALS
• Analysis of heat transfer coefficient of nano
fluids (Mr.V.N.Anbazhagan , IJERT 2013)
• Convective Heat Transfer Enhancement in
Nanofluids (American scientific publishers)
-experimental study

22. • A Review on Nanofluids: Preparation, Stability
Mechanisms and Applications (Wei Yu,
Huaqing Xai)
-method of preparation
• Heat transfer characteristics of nanofluids: a
review (Xiang-Qi Wang, Arun S. Mujumdar).