This document discusses a study on forced convection heat transfer of nanofluids in turbulent flow through an automobile radiator tube. It presents numerical simulations using a k-epsilon turbulence model to analyze heat transfer characteristics like heat transfer coefficient, heat flux, and Nusselt number for alumina and titanium dioxide nanofluids suspended in water. The results show that increasing nanoparticle concentration improves heat transfer but heat transfer enhancement decreases with increasing Reynolds number. Nanofluids have potential advantages for automotive cooling applications by improving radiator and engine performance.

1. Forced convection heat transfer of
nano fluids in turbulent flow in a flat
tube of an automobile radiator
 NAME :
NABYENDU
MUKHERJEE
 ROLL NO :
002211204003
 DEPT. : ME .
AUTOMOBILE
ENGG.[PG]
 YEAR : 1ST
YEAR 1ST SEM.
 JADAVPUR
UNIVERSITY

2. INTRODUCTION
Today’s engines
create a
tremendous
amount of heat.
Most of thisheat is
generated during
combustion.
Metal
temperatures
around the
combustion
chamber can run
as high as 1,000°F
(537.7°C).
Thisheat can
destroy the
engine and must
be removed.

3. INTRODUCTION
Nano fluids Base fluid
(e.g. Al2O3 or TiO2) (e.g. water)
Heat transfer coefficient Heat flux
Nusselt number Wall shear stress
Heat transfer enhancement
Concentration – 0 to 10%
Renolds number- 5000 to 20000

4. Nomenclature

5. Governing equations and turbulence model
▶ The CFD approach uses a numerical technique
to solve the governing equations for a given
geometry and boundary conditions.
conservation of mass
u i is the mean velocity vector

6. Equation of momentum conservation

7. k-ε turbulence model
Gk = turbulent kinetic energy generation due to mean velocity
gradients
Gb = turbulent kinetic energy due to buoyancy
YM = contribution of fluctuating expansion to compressible
turbulence.
C1ε=1.44 , C2=1.9, σk= 1, σε =1.2; Sε, Sk user defined terms

8. Turbulent viscosity

9. Nanofluids proprieties

10. Water proprieties

11. Modelling procedure
D=largest diameter(9mm)
d=smallest diameter(3mm)
L=length of the tube(345.0mm)
Dh=hydraulic diameter(4.68mm)

12. Boundary conditions
• concentration volume of nano particles of Al2O3 and
TiO2suspended in water of 1%, 2%, 3%, 4%, 6%, 8% and
10%
• inlet temperature was 363.15 K
• A constant velocity is imposed, with a flat profile
• Reynolds numbers between 5000 and 20000
• non-slip condition was imposed on the tube walls
• temperature at the tube wall is constant, 303.15 K
• Tube thickness is not considered
• the pressure outlet is equal to the atmospheric pressure

13. Mesh independence test
‣ Ansys Fluent, is used to perform computational
simulations to test the mesh independence
‣ A comparison was made for the Nusselt number
and for the friction factor obtained in the present
study
‣ three sizes meshing is considered
‣ Good agreement for mesh 2 and mesh 3, so mesh
3 was chosen, as it presents a better refinement
along the tube wall
‣ Mesh 3 gives better result due to time reduction
in the processing time when compared to mesh 2

14. Meshing

15. Mesh independence test friction
factor and average Nusselt number

16. Empirical equations to test
mesh independence

17. Results and discussion
• Turbulent flow with Reynolds numbers 5000,
10000, 15000 and 20000
• concentration of nanoparticles- varied
between 0% and 10%
• heat transfer coefficient and the heat flux are
analyzed along the different tube sections
(circular section and straight section)

18. Heat transfer coefficient for Al2O3-water nano fluid,
(a) on the circular section of the tube (line 1); (b) on
the straight section of the tube (line 2)

19. Heat transfer coefficient for TiO2-water nano fluid, (a) on
the circular section of the tube (line 1); (b) on the straight
section of the tube (line 2).

20. Heat flux for Al2O3-water nano fluid, (a) on the
circular section of the tube (line 1); (b) on the
straight section of the tube (line 2)

21. Heat flux for TiO2-water nano fluid, (a) on the
circular section of the tube (line 1); (b) on the
straight section of the tube (line 2).

22. Nusselt number vs Reynolds numbers for
various volume concentration, (a) of Al2O3
nanoparticles; (b) of TiO2 nanoparticles

23. Wall shear stress vs Reynolds numbers for various
volume concentration, (a) of Al2O3 nanoparticles;
(b) of TiO2 nanoparticles

24. Heat transfer enhancement
Nanoparticles E(%)
concentration
Reynolds number E (%)

25. Heat transfer enhancement at different volume
concentrations, (a) of Al2O3 nanoparticles; (b) of
TiO2 nanoparticles

26. Conclusions
• Increasing the concentration of nanoparticles
can improve the heat transfer characteristics
of nanofluids
• Use of alumina and titanium dioxide
nanoparticles have a similar behavior
regarding heat transfer
• The heat transfer enhancement decreases
with the increase of Reynolds number

27. Automobile perspectives
• Advantageous in the automotive industry,
advantage in the entire operating systems of
automobiles
• Utilization of nanofluids improve automobile
radiator performance
• Nanofluids can improve the heat transfer and
performance of the engine
• This nanotechnology can be integrated in
applications like engine cooling, engine
transmission oil

28. ThankYou