IRJET-Enhancing the Performance of Hybrid Microgrid using non Isolated Single Stage Three Port Converter: A Review

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 05 Issue: 06 | June 2018 www.irjet.net p-ISSN: 2395-0072
© 2018, IRJET | Impact Factor value: 7.211 | ISO 9001:2008 Certified Journal | Page 2601
HEAT TRANSFER ANALYSIS IN LIGHT PASSENGER CAR RADIATOR
WITH VARIOUS GEOMETRICAL CONFIGURATIONS
P.Natarajan1
1Assistant Professor, Dept. of Mechanical Engineering, Government College of Engineering, Bargur, India.
------------------------------------------------------------------***----------------------------------------------------------------------
Abstract-Now day’s uses of Automobile are becoming
high due to transportation. In Which radiator can
dissipate maximum amount of heat for any given space,
this has lead to the increased demand on the power
packed radiators. The research work is focused on the
Design and analysis of various aspects of single-phase
convective heat transfer. The Design and analysis of the
effects of various geometrical configurations on the
Performance of a staggered type fin and tube radiator is
presented. The method is demonstrated on fins-tube as
elements for the heat transfer, but it can in principle be
applied also to other geometrical configurations forms.
The study is conducted to investigate the effects of a tube
performance of the radiator having various geometrical
configurations. Samples of fin and tube heat exchanger
with transverse tube pitch of 13.87mm, tube outside
diameter of 6.35mm and longitudinal tube pitch of 12mm
are analysed in FLUENT 6.3. The radiator is made from
aluminium fin and tube. Hot water is used for the tube side
while atmospheric air is used as a working fluid in the air
side. The results are presented as contours of Velocity,
Pressure and Temperature with the fin length of the
Radiator.
Key Words: Staggered type pin and tube, transverse
tube pitch, longitudinal tube pitch, FLUENT 6.3.,
aluminium plate.
1. INTRODUCTION
Radiators are installed in automobiles to remove
heat from engine. When driving a car, the engine
produces intense heat which must be dissipated
otherwise the engine will overheat.
Somchai Wongwises et al [1] An experimental
study is conducted to investigate the effects of a fin pitch
and number of tube rows on the air side performance of
fin and tube heat exchangers having herringbone wavy
fin configuration at various thickness. A total of 10
samples of fin and tube heat exchanger with a tube
outside diameter of 9.53mm, transverse tube pitch of
25.4mm and longitudinal tube pitch of 19.05mm, having
various fin pitches.The heat exchangers are made from
aluminium plate finned, copper tube. Ambient air is used
as a working fluid in the air side while hot water is used
for the tube side. The experimental results revealed that
the fin pitch has an insignificant effect on the heat
transfer characteristic.
M. S. Sohal et al [2] reported the circular tubes
were removed instead of oval tubes and adding Winglets
in the fins. This results in increase of heat transfer
coefficient due to addition of winglets.
Ke-Wei Song et al [3] studied Winglets mounted
on surfaces of the fin which increases heat transfer
instead of tube bank fin heat exchanger.
J. He et al [4] experimentally investigated plain-
fin round-tube heat exchanger in wind-tunnel testing.
Winglet pairs are placed at an angle of 10 deg and 30 deg
compared with pair 30 deg angle of attack produced
better performance.
Jae dong Chung et al [5] reported numerical
analysis is conducted on the rectangular winglet pair
with plate heat exchanger to examine the louver fins and
vortex generators combined effects. The test was
conducted various angle of attack from in this 30 deg
angle gave the better performance.
K.M.Kwak et al [6] investigated longitudinal
vortices mounted air-cooled condensers. Result reveled
that in –line arrangement of fin-tube have better thermal
performance than staggered arrangement.
2. PROBLEM DEFINITION
Aerodynamic front end styling with narrower
openings are decreasing the space available for
circulation of cooling air.
These conditions demand a better
understanding of the cooling fluid flow direction and
thermal performance of the radiator to analysis various
geometry configurations using CFD.

3. DESIGN AND ANALYSIS
The radiator of a commercially existing vehicle
is chosen for the analysis to bring in the practicality to
the study. The details of the geometry of the radiator
were obtained by the process of reverse engineering.
The dimensions of individual components of the radiator
were measured using suitable measuring instruments
then used to generate the Gambit model.
Discrediting the fluid domain, simulation of the
fluid flow with heat transfer at steady state and post
processing the results and drawing suitable conclusions.
3.1 RADIATOR SPECIFICATIONS
Radiator type = staggered
Number of tube rows (N) = 25
Number of tube columns = 2
Radiator material = Aluminium
Tube outside diameter (do) = 6.35mm
Tube inside diameter (di) =5.35mm
Tube thickness (Tt) = 0.5mm
Longitudinal tube Pitch (S L) =12 mm
Transverse tube pitch (S T) =13.87 mm
Diagonal tube pitch (S D) = 13.87mm
Fin thickness (Ft) = 0.3mm
Fin spacing (FS) = 1.60 mm
Fin pitch (FP) = 1.90 mm
Length of radiator (L) = 300 mm
Depth of radiator (D) = 28 mm
Fig- 3.1: GAMBIT Model
3.2 INLET CONDITIONS
Inlet temperature of air (30 °c)
Air density (ρ) = 1.165 kg/m3
Air viscosity (µ) = 18.63 × 10 -6 Ns / m2
Thermal Diffusivity (α) = 22.861 × 10-6 m2/s
Prandtl number = 0.701
Specific heat (Cp) = 1.005 KJ/Kg K
Thermal conductivity of air (k) = 0.02675 W / m K
Inlet temperature of water (90 °c)
Water density (ρ) = 967.5 kg/m3
Water viscosity (µ) = 0.315× 10 -3 Ns / m2
Thermal Diffusivity (α) = 0.16585 × 10-6 m2/s
Prandtl number = 1.98
Thermal conductivity of air (k) = 0.67455 W / m K
Aluminium Properties
Aluminium density (ρ) = 2700 kg/m3
Thermal conductivity of Al (k) = 202.4 W / m K
Hydraulic diameter of fin for air side
Hydraulic diameter = 4A / p (5.5)
Where,
A = Cross Sectional Area, P = Perimeter
= 4× 41.8×1.6 / 2 (41.8 + 1.6)
= 267.52 / 86.8
= 3.08 mm
Hydraulic diameter of tube for water side
Hydraulic diameter = 4A / p (5.6)
Where,
A =Cross Sectional Area, P = Perimeter
= (4×π / 4 × di
2 ) / π di
= 5.35 mm
Re = ρ V d / µ (5.7)
V1 = (1000×18.63 × 10 -6)/1.165×0.00308
= 5.1920 m/s
Where,
ρ = 1.165 Kg/m3
Re = 1000
d = 3.08 mm
µ - 18.63 × 10 -6 Ns / m2
3.3 COMPUTATIONAL DOMAIN AND
BOUNDARY CONDITIONS
The model for current study, consist of the
computational domain of dimensions are 41.8 mm
length, 4.2 mm width, and 28 mm height. Sketch of the
computational domain is as per fig 3.3(a). The cooling fin
base area is the same for all models. The inlet velocity of
air V various (V1= 5.1920 m/s, 19.145 m/s, 15.576 m/s,
20.768 m/s, 25. 968 m/s) and the inlet temperature Ti is
assumed uniform through the entire boundary
equivalent to Reynolds Number of 1000 to 5000
respectively at inlet temperature of Tin = 303 K (Pr =
0.7). Water of the tube are smooth, and have the inlet
velocity of water V (V1= 5.1920 m/s) and the inlet
temperature Tin are assumed uniform through the entire
boundary. For all cases, the incompressible hot fluid is
water at 363 K. The shape chosen are circular, oval tubes
and the fin spacing on the heat transfer is 1.6mm.

Fig- 3.3(a): Schematic of a computational domain
Fig- 3.3(b): Computational domain
The computational domain was as per fig-3.3(a)
and fig-3.3(b), shows a schematic and Gambit model for
the computational analysis respectively. The model
having a width, length and height. The domain consists
of tube and fin defined as air and water.
The geometric similarity between the rows of
tube and fin helps us in limiting the computational
domain to a four tube and adjoining fin arrangement.
Hence, the fluid domain is created for a double fin and
tube assembly and design analysis is carried out. The
fluid domain includes the air flow volume and the
coolant flow volume. The problem is solved as a
conjugate heat transfer requiring the thickness of the
tube and fin also to be modeled.
Fig- 3.3(c): Mesh model from GAMBIT
In Gambit model the fin spacing is air domain,
tube is hot water domain, tube thickness and fin
thickness are discredited with same mesh density in
accordance to the physics of fluid flow and heat transfer.
The grid independence study of the simulation is carried
out to arrive at the minimum number of elements
required to maintain the required stability and accuracy
in the computation. The finalized element count and the
related aspects are listed below .The meshed geometry
for a four tubes and double fin assembly of the radiator
as shown in fig 3.3(c).
Element count in tube-fin assembly
Number of Hexahedral cells = 8904
Number of quadrilateral cells = 33678
Total Number of Cells = 42582
Skewness = 0.97%
4. RESULTS AND DISCUSSION
4.1 Contours of velocity magnitude
Design and Analysis of a single elliptical cylinder
with a minor to major axes ratio of 1, 0.69, 0.47 , 0.909
and 1.1 in a flow of air having Reynolds numbers of
1000 < Re d <5000 with angles of attack 0 °. Re d is the
Reynolds number based on the shape of circular tube
and Various oval tube conditions. A different velocity
field around the circular tube staggered arrangement
could be observed compared with that of the oval tube
staggered arrangement.Whereas the flow through the
staggered arrangement periodically separates and joins
again. Further, because in the staggered arrangement
each tube is located in the adjacent of the previous pins,
the flow separated from the first tube row not hits at
second rows tubes.So each tube makes separate
boundary layer.
Air outlet
Air inletWater inletSolid zone
Air zone
Water
outlet

Fig-(4.1a): Circular tube (Ratio=1)
Fig-(4.1b): Oval tube (Ratio=0.69)
Fig-(4.1c): Oval tube-I (Ratio=0.47)
Fig-(4.1d): Oval tube-II (Ratio=0.909)
Fig-(4.1e): Oval tube-III (Ratio=1.1)
Fig- 4.1: Contours of velocity magnitude
4.2 Contours of Static Temperature

Fig- 4.2: Contours of static temperature
The thermal characteristics of the convective
heat transfer from fin-tube can be observed on the
temperature field in fluid and solid parts of the
computation domain. The complete temperature
changes in the computation domain. The presented
temperature fields, as expected, shows that the thermal
boundary layer develops around tubes, but thickest
thermal boundary layers around the tubes when more
amount of heat is absorbed in air by convection. whereas
for the subsequent rows, quite small temperature
differences between the tubes and the air were observed
.Here it should be mentioned that the intensive reduction
of the temperature difference between the tubes and the
surrounding air in addition to the fin cross-section and
surrounding velocity field depends also on the fin
material chosen. The temperature difference between
circular tubes and oval tubes occur but circular tubes
shows higher temperature values than oval tubes.

4.3 Contours of static pressure

Fig- 4.3: Contours of static pressure
The flow across a cylinder when flow field can
be divided into two regions. A boundary layer region
near the surface and inviscid region away from the
surface. The pressure gradient along the surface of the
cylinder is not zero, and in fact this pressure gradient is
responsible for the development of a separated flow
region on the back side of the cylinder. The separation of
flow affects the drag force on a curved surface to a great
extent.
5. PERFORMANCE EVALUATION
The outlet temperature performance of existing
circular tube and various geometrical configurations are
oval tube, oval tube-I, oval tube-II, oval tube-III. Inlet of
fin side air velocity and air temperature are applied
based on the hydraulic diameter of the fin areas. Outlet
temperature of oval tube-III have higher ranging value
than existing circular tube values.
Fig- 5.1: Outlet temp Vs fin length
The fig-5.1 shows outlet temperature of various
geometrical configurations for entire fin length. The air
entre to the atmospheric conditions parallel to major
axis when increase major axis value then decrease the
out let temperature range. So change the major to minor
axis ratio = 1.1 when atmospheric air entre parallel to
the minor axis then increase outlet temperature values.
The inlet pressure drop performance of existing
based on the hydraulic diameter of the fin areas.
Pressure drop of oval tube-III higher ranging value than
existing circular tube values.
Fig- 5.2: Pressure Vs fin length
The fig-5.2 shows pressure drop of various
axis when increase major axis value then decrease the
pressure drop range. So change the major to minor axis
ratio = 1.1 when atmospheric air entre parallel to the
minor axis then increase pressure drop values.
The outlet velocity performance of existing
based on the hydraulic diameter of the fin areas. Outlet
velocity of oval tube-III higher ranging value than
existing circular tube values.
Fig- 5.3: Outlet velocity Vs fin length
The fig- 5.3 shows outlet velocity of various
axis when increase major axis values then decrease the
outlet velocity range. So change the major to minor axis

ratio = 1.1 when atmospheric air entre parallel to the
minor axis then increase outlet velocity values.
6. CONCLUSIONS
The fluid flow and heat transfer analysis of a
staggered type tube-fin arrangement of an automotive
radiator is successfully carried out by using numerical
simulation built in commercial software FLUENT. The
variations of the pressure, temperature and Velocity in
the direction of coolant flow and air flow are presented
and analysed.
The outlet temperature and maximum velocity
for circular and oval tube-III are nearly same other oval
tube, oval tube-I, oval tube-II are less than oval tube-III.
Pressure is high for oval tube-III than circular tube.
REFERENCE
[1] Somchai wongwises, and yutasak chokeman,
“Effect of fin pitch and number of tube rows on
the air side performance of a herringbone wavy
fin and tube heat exchangers,’’2002 Elsevier Ltd.
[2] M. S. Sohal, and J. E. O’Brien,”Improving air-
cooled condenser performance using winglets
and oval tubes in a geothermal power
plant,’’Geothermal Resources Council
Transactions,2001, Vol. 25, pp.1-7.
[3] Ke-Wei Song, Liang-Bi Wang, Ju-Fang Fan, Yong-
Heng Zhang, and Song Liu,‘’Numerical study of
heat transfer enhancement of finned flat tube
bank fin with vortex generators mounted on
both surfaces of the fin’’, 2007,Heat and Mass
Transfer, Vol. 44, pp.959-967.
[4] J. He, L. Liu, and A. M. Jacobi,‘’Air-Side Heat-
Transfer Enhancement by a New Winglet-Type
Vortex Generator Array in a Plain-Fin Round-
Tube Heat Exchanger’’,2010 Journal of Heat
Transfer, Vol. 132, pp.1-9.
[5] Jae dong chung, Byung kyu park, and Joon sik
lee,‘’The combined effects of angle of attack and
louver angle of a winglet pair on heat transfer
enhancement’’, International Journal of
enhanced Heat Transfer,2003, Vol.10, pp.31-43.
[6] K.M. Kwak, K. Torii, and K. Nishino, ‘’Heat
transfer and flow characteristics of fin-tube
bundles with and without winglet-type vortex
generators’’, 2002, Springer,Vol.33, pp.696-702.

IRJET-Enhancing the Performance of Hybrid Microgrid using non Isolated Single Stage Three Port Converter: A Review

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