This document outlines a project to design and fabricate a cooling system using ferrofluids. Ferrofluids are magnetic liquids that can be controlled using magnetic fields. The project involves synthesizing an aqueous ferrofluid and designing a system with a test section, pump, temperature sensors, heater and sink. When a temperature gradient is applied with a magnetic field, thermomagnetic convection occurs in the ferrofluid due to differences in magnetic susceptibility, enhancing heat transfer for cooling applications. The system is designed to test this effect and optimize heat transfer performance using ferrofluids.

1. DESIGN AND FABRICATION OF A COOLING
SYSTEM UTILIZING THE THERMO-MAGNETIC
CONVECTIVE BEHAVIOUR OF FERROFLUID
A Project Report
Submitted By
Suryakumar A.S
Prasanth Rajasekaran
Ragav Giridharan
Santhosh Kumar R
in partial fulfillment for the award of the degree
of
BACHELOR OF ENGINEERING
in
MECHANICAL ENGINEERING
COLLEGE OF ENGINEERING, GUINDY
ANNA UNIVERSITY::CHENNAI 600 025
AUGUST 2013

2. ANNA UNIVERSITY : CHENNAI 600 025
BONAFIDE CERTIFICATE
Certified that this project report "DESIGN AND FABRICATION OF A
COOLING SYSTEM UTILIZING THE THERMO-MAGNETIC
CONVECTIVE BEHAVIOUR OF FERROFLUID" is the bonafide work of
" Suryakumar A.S , Prasanth Rajasekaran, Ragav Giridharan, Santhosh
Kumar R" who carried out the project work under my supervision.
SIGNATURE
Dr. B. Mohan
SUPERVISOR
Associate Professor
Department of Production Technology
Madras Institute Of Technology,Chromepet
Chennai-600 044

3. Abstract
The project proposes a novel method for cooling system using super
paramagnetic fluid called Ferrofluids. Ferrofluids are colloidal suspension of
nano-sized ferromagnetic particles dispersed in a carrier liquid. Ferro fluids
becomes magnetized in the presence of external applied magnetic field, but its
magnetic susceptibility drops as it approaches its curie temperature. The work
concentrates on the synthesis of Ferro-fluids followed by using its temperature
dependent magnetism to induce a Thermo magnetic convection for a cooling
system.
Project Progress
 Synthesis of organic Ferrofluid
 Rejection of organic Ferrofluid on account of incompatible base fluid
 Selection of Aqueous Ferrofluid
 Decision on cooling system dimension and capacity
 Decision on components and specification
 Finalizing layout of cooling system

4. TABLE OF CONTENTS
CHAPTER NO. TITLE PAGENO.
1. INTRODUCTION 1
2. THEORY
i. Curie Law
ii. Thermomagnetic Convection
2
3. FERROFLUID PREPARATION
i. Preparation of organic ferrofluid
ii. Preparation of Aqueous ferrofluid
3
4. COOLING SYSTEM COMPONENTS
i. Test Section
ii. Pump System and flow meter
iii. Resistance Temperature Detector
iv. Heating system and Sink
4
5. COOLING SYSTEM LAYOUT 7
6. REFERENCES 8

5. 1. INTRODUCTION
Convectional heat transfer fluids, such as water, oil and ethylene glycol with
low thermal conductivity causes serious limitations in improving the
performance of many engineering equipments, such as heat exchangers and
electronic devices. To overcome this disadvantage, great attempt has been
accomplished in order to substitute heat transfer fluids with higher thermal
conductivity. An innovative way for enhancing the thermal conductivity of the
fluids is the use of nanofluids, One such fluid being ferrofluids.
Ferrofluids consists of a suspension of nano ferromagnetic particles in a carrier
fluid. The particles are typically at the range of 10 nm in diameter, which is
coated with adsorbed surfactant layers to keep a stable suspension state. In the
absence of an applied magnetic field, the particles are randomly oriented, and
the fluid has no net magnetization. However, in the presence of magnetic field ,
the nano particles like to align with the external applied magnetic field.
Ferrofluids have remarkable potential for heat transfer applications because
their thermo magnetic convection can be controlled by varying ferrofluid
properties, the magnetic field strength, and also the temperature distribution.
The fabrication project looks to design a prototype cooling system using the
enhancement of ferrofluid heat transfer in the presence of a magnetic field.
Based on the means of suspension it can be classified as surfacted ferrofluid or
Ionic Ferrofluid.
2. THEORY
i. Curie Law
The magnetisation of a paramagnetic substance is inversely proportional to the
temperature.
M is the resulting magnetisation

6. B is the magnetic field
T is the absolute temperature
C is the Curie Constant
ii. Thermo magnetic Convection
Property of ferrofluid wherein the presence of a temperature gradient, a
convection is introduced following curie’s law
The heated ferrofluid is less attracted to the magnetic field in comparison
with the cooler ferrofluid which being strongly attracted to the magnetic
field sets up a convective flow by displacing the hotter ferrofluid.
3. FERROFLUID PREPARATION
i. Preparation of organic ferrofluid
Chemicals Required:
 1.5M FeCl3 solution
 1.5M FeCl2 solution
 Household Ammonia
 Oleic Acid
 Organic Base Fluid
Procedure:
1. Mix 2:1 ratio of FeCl3:FeCl2
2. Add household ammonia slowly to the mixture,Fe3O4 precipitates out
3. Heat the Solution to near boiling (about 95 degrees)
4. Add Oleic acid slowly to the heated solution
5. Heat till scent of ammonia has faded
6. Add organic base fluid and separate ferrofluid out

7. 2FeCl3 + FeCl2 + 8NH3 + 4H2O Fe3O4 + 8NH4Cl
ii. Preparation of Aqueous ferrofluid
Chemicals Required:
 1.5M FeCl3 solution
 1.5M FeCl2 solution
 Household Ammonia
 Tetramethylammonium Hydroxide
Procedure:
1. Mix 2:1 ratio of FeCl3:FeCl2
2. Add household ammonia slowly to the mixture,Fe3O4 precipitates out
3. Decant out household ammonia and rinse with water
4. Add Tetramethylammonium Hydroxide to the mixture to obtain
Ferrofluid
2FeCl3 + FeCl2 + 8NH3 + 4H2O Fe3O4 + 8NH4Cl
4. COOLING SYSTEM COMPONENTS
v. Test Section
Copper tubing is decided for the test section for its high conductivity so
as to neglect its contribution to overall heat transfer coefficient.
Inner diameter- 10mm
Length- 400mm
Thickness- 5mm

8. These dimensions were chosen based on previous experiments conducted on
ferrofluid heat transfer and to meet our constraint on the amount of ferrofluid to
produce.
vi. Pump System and Flow meter
vii. Resistance Temperature Detector
Possible choices are 3 wire or 4 wire RTD. Cost, availability and accuracy
would be the deciding factor, with deviation of no more than 1.5 degree Celsius
is required.
viii. Heating system and Sink
Nichrome coil heater is preferred for the setup taking into account
availability and cost
A simple water bath was decided to act as a sink.
5. COOLING SYSTEM LAYOUT

9. REFERENCES
1. Masaaki Motozawa, Yasuo Kawaguchi, Effect Of Magnetic Field On
Forced Convective Heat Transfer In Rectangular Duct Flow Of a
Magnetic Fluid, International Symposium on Transport Phenomena
Proceedings.
2. Maryamalsadat Lajvardin, Jafar Moghimi-Rad,Iraj Hadi,Anwar
Gavili,Taghi DallaliIsfahani, Fatemeh Zabihi,Jamshid Sabbaghzadeh,
Experimental investigation for enhanced ferrofluid heat transfer under
magnetic field effect, Journal of Magnetism and Magnetic Materials
322(2010)3508–3513
3. Mengfei Yang, Robert O’Handley and Zhao Fang, Modeling of
Ferrofluid Passive Cooling System, Proceedings of the COMSOL
Conference 2010 Boston
4. C. Scherer and A. M. Figueiredo Neto, Ferrofluids: Properties and
Applications, Brazilian Journal of Physics, vol. 35, no. 3A, September,
2005
*****

10. ANNA UNIVERSITY : CHENNAI 600 025
BONAFIDE CERTIFICATE
Certified that this project report "DESIGN AND FABRICATION OF A
COOLING SYSTEM UTILIZING THE THERMO-MAGNETIC
CONVECTIVE BEHAVIOUR OF FERROFLUID" is the bonafide work of
" Suryakumar A.S , Prasanth Rajasekaran, Ragav Giridharan, Santhosh
Kumar R" who carried out the project work under my supervision.
SIGNATURE
Dr. B. Mohan
SUPERVISOR
Associate Professor
Department of Mechanical Engineering
College Of Engineering,Guindy
Chennai-600 025