International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016)
Experimental Design and Manufacturing of Compound Al
(1060) Fins and Heat Transfer Analysis on Perforated
Staggered Fins
MdMaroofMd Nayeem#1, Prof.Rahul D. Shelke*2
#
PG Scholar,*Professor & Mechanical Engineering&BAMU Aurangabad
EE’sCOE&T Aurangabad, Maharashtra, India.
Abstract— The present experiment involves
design and manufacture of Aluminium AL-1060 fins.
Two different kinds of fin designs have been
considered, first type with a base square up to half the
height while remaining portion cylindrical and the
second type of fin which is vice versa i.e. cylindrical
base up till half the height and remaining portion in
square shape. Heat transfer analysis has been done on
enhancement and the corresponding pressure drop
over a flat surface equipped with Compound Square
cylindrical cross-sectional perforated pin fins in a
rectangular channel as well as over a flat surface
equipped with rectangular cross sectional perforated
fins. The channel had a cross-sectional area of 250 x
250 mm2. The experiments covered the following
parameters: Reynolds number 13,500– 42,000, the
inter-fin spacing ratio (Sy/D) 1.208, 1.944 and 3.417.
The heat transfer rate, friction factor and
enhancement efficiency were developed by correlation
equations. The experimental results show that the use
of the above mentioned designs lead to heat transfer
enhancement. Enhancement efficiencies varies
depending on the inter-fin spacing ratio. Suggested for
higher thermal performance gain by take both lower
inter-fin spacing ratio and comparatively lower
Reynolds numbers. Nusselt number and friction factor
were considered as performance parameters.
A. Aluminium Materials:
Aluminium is a chemical element in the boron group
with symbol Al and atomic number 13. It is a silverywhite, soft, nonmagnetic, ductilemetal. Aluminium is
the third most abundant element (after oxygen and
silicon), and the most abundant metal in the Earth's
crust. It makes up about 8% by weight of the Earth's
solid surface. Aluminium metal is so chemically
reactive that native specimens are rare and limited to
extreme reducing environments. Instead, it is found
combined in over 270 different minerals.[7] The chief
ore of aluminium is bauxite. Aluminium is remarkable
for the metal's low density and for its ability to resist
corrosion due to the phenomenon of passivation.
Structural components made from aluminium and its
alloys are vital to the aerospace industry and are
important in other areas of transportation and
structural materials. The most useful compounds of
aluminium, at least on a weight basis, are the oxides
and sulphates.
1) Aluminium AL-1060
1060 aluminium alloy is an aluminium-based alloy in
the commercially pure wrought family (1000 or 1xxx
series). It is fundamentally very similar to 1050
aluminium alloy, with the difference coming down to
0.1% aluminium by weight. However, while both
Keywords—Al-1060 Material, Force Convection
1050 and 1060 are covered by the same ISO standard,
Heat Transfer, Square Cylindrical perforated Fins,
they are covered by different ASTM standards. As a
Force Convection Heat Transfer, Staggered
wrought alloy, it is typically formed by extrusion or
Arrangement, Turbulence Flow.
rolling. It is commonly used in the electrical and
chemical industries, on account of having high
I. INTRODUCTION
electrical conductivity, corrosion resistance, and
Manufacturing is the backbone of any industrialized workability. It has low mechanical strength compared
nation. Manufacturing and technical staff in industry to more significantly alloyed metals. It can be
must know the various manufacturing processes, strengthened by cold working, but not by heat
materials being processed, tools and equipment‟s for treatment.
manufacturing different components or products with
Alternate designations include Al99.6 and
optimal process plan using proper precautions and A91060. It is described in the following standards
specified safety rules to avoid accidents. Beside above,
ASTM B 209: Standard Specification for
all kinds of the future engineers must know the basic
Aluminium and Aluminium-Alloy Sheet and
requirements of workshop activities in term of man,
Plate
machine, material, methods, money and other
ASTM B 210: Standard Specification for
infrastructure facilities needed to be positioned
Aluminium and Aluminium-Alloy Drawn
properly for optimal shop layouts or plant layout and
Seamless Tubes
other support services effectively adjusted or located
ASTM B 211: Standard Specification for
in the industry or plant within a well-planned
Aluminium and Aluminium-Alloy Bar, Rod, and
manufacturing organization.
Wire
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ASTM B 221: Standard Specification for
Aluminium and Aluminium-Alloy Extruded Bars,
Rods, Wire, Profiles, and Tubes
ASTM B 483: Standard Specification for
Aluminium and Aluminium-Alloy Drawn Tube
and Pipe for General Purpose Applications
ISO 6361: Wrought Aluminium and Aluminium
Alloy Sheets, Strips and Plates
B. Heat Transfer:
Heat transfer is a science that studies the energy
transfer between two bodies due to temperature
difference. This temperature difference is thought of
as a driving force that causes heat to flow. Heat
transfer occurs by three basic mechanisms or modes
conduction, convection, and radiation.The term of
extended surface is commonly used in reference to a
solid that experiences energy transfer by conduction
and convection between its boundary and
surroundings. A temperature Gradient in x-direction
Systems heat transfer by convection internally, at the
same time, there is energy transfer by convection into
an ambient temperature from its surface at
temperature. When the surface temperature and
ambient temperature are fixed by design
consideration, then there are only two ways to increase
the heat transfer rate [1] to increase the convection
coefficient h, or [2] to increase surface area A. for heat
transfer from a hot fluid to a gas through a wall, the
value of heat transfer coefficient on gas side is usually
very less compared to that for fluid. To compe1nsate
low heat transfer coefficient, the area on the gas side
may be expended for a given temperature difference
between surface and its soundings these extended
surface is called Fin.
II. EXPERIMENTAL SETUP
A. Main Tunnel:
Tunnel constructed of wood of 20 mm thickness, had
an internal cross-section of 250 mm width and 100
mm the total length of the channel is 1000 mm. It will
be operated in force draught mode by the blower of
0.5 H.P., 0 to 13000 rpm, 220W, 1.8Kg, variable
speed 1 to 6 and it is fitted at 45cm away from the
entry of the tunnel positioned horizontally and flow of
air is controlled by the flow control valve mounted
just after the blower. It has a convergent and divergent
section at both ends having the inclination of 30°. A
Matrix anemometer is mounted in a tunnel to measure
the mean inlet velocities of the air flow entering to the
test section the range of this anemometer is 0 to
40m/sec. The Reynolds number range used in this
experiment was 13,500–42,000, which is based on the
hydraulic diameter of the channel over the test section
(Dh) and the average velocity (U) The inlet and outlet
temperature of the air stream and temperature of base
plate will be measured by RTD Sensors having a
range of 0°c to 450°c which mounted in wind
tunnel.[4][11]
ISSN: 2231-5381
B.Heater Unit:
Heater Unit (test section) has a cross-section of 250
mm x 250 mm square; the heating unit mainly
consisted of an electrical heater placed between two
M.S. Plate having the same dimension of base plate, a
two firebrick of 250x 220 mm. Dimensions of the
electrical heater placed on the firebrick are 250 mm x
250 mm. The heater output has a power of 200 W at
220V and a current of 10 amp.
C. Base Plate:
It consist of square plate at base having the dimension
250mm x 250 mm, thickness is 6mm and The pin fins
and base plate made of the same material i.e.
Aluminium because of the considerations of
conductivity, machinability and cost. The base of fins
have a Square cross section of 15 mm x15 mm of
height 50mm, on which the Cylindrical Shape fins
having Diameter 15 mm and are attached on the
upper surface of the base plate as shown in Figureand
vase-versa same dimension but the base Circular is
bottom and upper is square pin fins with different
lengths, corresponding to C/H (Clearance ratio) values
of 0, are perforated at the 17 mm from bottom tip of
those by an 8 mm diameter drill bit. The pin fins are
fixed uniformly on the base plate with a constant
spacing between the span wise directions of 18.125
mm, with different spacing between the pin fins in the
stream wise direction. The spacing ratios of the pin
fins in the stream wise direction (Sy/D) were 1.208,
1.524 and 3.417 mm, giving different numbers of the
pin fins on the base plate. It is well-known fact that if
the inter-fin spacing in the span wise direction
decreases, the flow blockage will increase and thus,
pressure drop along to tested heat exchanger will
increase. Because the aim of the study is to determine
inter-fin spacing in stream wise direction, the
spacing‟s in the span wise direction will not be
considered in this study. The temperature of the base
plate is measured RTD Sensors which can sense the
temperature from 0°c to 450°c and it is screwed into
groove in the base plate the readings of the RTD
Sensors will be shown on data unit
Fig.1 A sample line graph using Base Plate of
Compound Fin in Staggered arrangement [11].
III. EXPERIMENTAL SET-UP FACILITY
The range of Reynolds number used in this
experiment
13,500 to 42,000, the average velocity (U) and
hydraulic diameter of the channel over the test section
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(Dh) these twoparameter are used to calculate the
Reynolds number. The inletand outlet temperature of
the air stream will be measured RTDSensors which
mounted in wind tunnel. One RTD Sensors forthe
outer surface temperature of the heating section and
one forthe ambient temperature is employed The
pressure drop acrossthe test model is measured using
two pressure transducers thatcan take measurements
between 0 and 150 Kg/cm² whichmounted in wind
tunnel.Tunnel constructed of wood of 20 mm
thickness, had aninternal cross-section of area 250 mm
× 250 mm and 100 mmthe total height of tunnel the
length channel is 1000 mm. Theair supplied into the
tunnel over Fin with the of blower, which have
adjustable speed i.e. 2,3,4,5 m/s and range of rotation0
to 12000 rpm and it is fitted at entry of tunnel i.e.
atconvergent part of tunnel and positioned
horizontally. It has aconvergent and divergent section
at both ends having the inclination of 30°. A
anemometer measured the average inletvelocities of
the air flow entering to the test section theanemometer
is mounted inlet of a tunnel the range of
thisanemometer is 0 to 5 m/sec.[11]
comes in operation and start the power supply of
heater and cycle gets repeat.[11][4]
Now switch on the blower and measure the
velocity of inlet air by using digital anemometer.
Make the inlet air velocity constant at required
velocity by regulating the speed of blower i.e.
2m/s, 3m/s, 4m/s, and 5m/s.[4]
Now air will pass over heated base plate through
tunnel
Measure the outlet temperature of outgoing warm
air.
Now due to forced convection the temperature of
base plate falls below 100˚C. As soon as the
temperature of base plate falls below the 100˚C
heater unit will start heating the base plate to
achieve the constant 100˚C temperature by
supplying constant electrical input as the air is
continuously flowing over the base plate heat get
transferred from it to the flowing air. Thus the
temperature of base plate falls continuously and
takes the temperature readings of base plate after
90 seconds of air flow. The duration of air flow is
constant for all types of base plate mentioned
above.[4][11]
Similarly, repeat the same procedure for velocity
3m/s, 4m/s, and 5m/s and take the similar readings. [4]
V. MATHEMATICAL RELATIONSHIP
A. TOTAL AREA OF FINS:
TOTAL AREA = PROJECTED AREA + TOTAL SURFACE
AREA CONTRIBUTION FROM THE BLOCKS [9]
Fig.2. Experimental Set-up
IV. EXPERIMENTAL PROCEDURE
First of all make all the necessary attachment to
wooden tunnel required for experimental set-up
i.e, attachment of data unit, attachment of blower
unit, attachment of heater unit. [4][11]
Keep the Aluminium base plate of required
dimensions on heater unit. [11]
Move the heater unit upward by rotating the
screw jack.
Switch on the RTD sensors of inlet, outlet and
base plate temperature indicator and check
whether it is properly functioning or not.[4]
Measure the room temperature by anemometer by
changing the function of it to temperature mode.
Switch on the heater, as soon as base plate
temperature reached up to 100˚C, the temperature
controller of RTD sensors comes in operation and
it will cut off the power supply of heater. Once
the temperature of base plate reduced up to 99˚C
again temperature controller of RTD sensors
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B. Heat Transfer:
Where: Q indicates the heat transfer rate in which
subscripts conv, elect, cond and rad denotes
convection, electrical, conduction and radiation,
respectively [3]. The electrical heat input is calculated
from the electrical potential and current supplied to
the surface.
Where:-‘I’ is current flowing through the heater and
‘R‟ is the resistance.
The heat transfer from the test section by convection
can be expressed as [7]
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increase the turbulence of the flow in the channel,
resulting in an increase in the heat transfer. It is also
shown from Fig. 3 & 4 that due to the multiple jet-like
flows, the enhancement in the heat transfer with
perforated fins is higher than that with the solid fins
for all the values of studied.
C. Friction Factor:
This equation is valid for 13,500 < Re < 42,000, 1.208
<Sy/ D < 3.417, 0 < C/H < 1 with a correlation
coefficient of r = 0.980.On the other hand, as the
resistance to the flow will be smaller due to the
perforations, friction factor is lower for the perforated
fins than the solid fins.[9]
D. Nusselt Number:
Nu based on the projected area will reflect the effect
of the variation in the surface area as well as that of
the disturbances in the flow due to fins on the heat
transfer. But Nu based on the total area will reflect the
effect of the flow disturbances only. In this study, heat
transfer enhancement characteristics were determined
by using Nu-based projected area, while optimization
was made by using Nu based total area [11].
The average Nusselt number (Nus) for the smooth
surface (without pin fins) was correlated as function of
Re and Pr as follows: [5]
The Nusselt number based on both the projected area
and total area was related to the Reynolds number,
clearance ratio (C/H), inter-fin distance ratio (Sy/D)
and Prandtl number. Thus, the following correlation
equations were obtained: [9]
Fig.3.Variation of Nu/Nus based on Projected area with
Reynolds No. at Sy/D=1.208 for Base Square
Fig.4.Variation of Nu/Nus based on Projected area with
Reynolds No. at Sy/D=1.208 for Base Cylindrical
It is also shown from Fig. no.3&4 that due to the
multiple jet-like flows, the enhancement in the heat
transfer with perforated fins is higher than that with
the solid fins for all the values of studied.
E. Effectiveness:
The enhancement efficiency of the heat transfer
technique for a constant pumping power can be
expressed as [9]
Where ha and hs are the convective heat transfer
coefficient with and without pin fins, respectively, and
the index p denotes the pumping power. [9]
Fig.5. Variation of friction factor with Reynolds number for various
Sy/D ratios of Base Cylindrical.
VI. RESULTS & ANALYSIS
A. Nusselt Number:
The Nusselt number that is based on the projected area
will reflect the effect of the variation in the surface
area as well as that of the disturbance in the flow due
to pin fins on the heat transfer. Longer fins can also
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(c) At a lower Reynolds number, the channels with pin
fin arrays give higher performance than those at a
higher Reynolds number.
Fig.6. Variation of friction factor with Reynolds number for various
Sy/D ratios of Base Square.
The other table result is seen from Fig. no. 5 &6 for
the friction factor. The friction factor values are
almost independent of the Reynolds number. It is
emphasized in another optimization study for a finned
heat exchanger that interestingly, stream wise distance
between fins is more effective parameter on the
friction factor than span wise distances. On the other
hand, as the resistance to the flow will be smaller due
to the perforations, friction factor is lower for the
perforated fins than the solid fins.
Fig.7. Variation of enhancement efficiency (g) with Reynolds
number for various inter-fin spacing ratios.
Fig. no. 7 Show the effect of the inter-fin distance
ratio on Effectiveness. For a net energy gain, the value
of the g must be greater than unity. In other words, for
an effective heat transfer enhancement technique, it
must have values greater than unity. FromFig. 07, it is
apparent that as the Reynolds number increases, the
enhancement efficiency decreases for both the interfin spacing ratio. Fig. 07 shows that the heat transfer
enhancement efficiency decreases with increasing
Sy/D. In other words:
(a) The heat transfer enhancement efficiencies are
higher than unity for all investigated conditions. This
means that the use of pin fins leads to an advantage on
the basis of heat transfer enhancement.
(b) Higher numbers of pin fins and longer pin fins
have better performance. In other words, for higher
thermal performance, a lower inter-fin distance ratio
and clearance ratio should be preferred.
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VII.
CONCLUSION
In this study, the overall heat transfer, friction factor
and the effect of the various design parameters on the
heat transfer and friction factor for the heat
experiment equipped with cylindrical cross-sectional
perforated pin fins were investigated experimentally.
The effects of the flow and geometrical parameters on
the heat transfer and friction characteristics were
determined, and the enhancement efficiency
correlations have been obtained. The conclusions are
summarized as:
(a) The average Nusselt number calculated on the
basis of projected area increased with decreasing
inter-fin spacing ratio.
(b) The friction factor increased with decreasing
inter-fin distance ratio.
(c) Enhancement
efficiencies
increased
with
decreasing
Reynolds
number.
Therefore,
relatively lower Reynolds number led to an
improvement in the heat transfer performance.
(d) The most important parameters affecting the heat
transfer are the Reynolds number, fin spaces
(pitch) and fin height. Heat transfer can be
successfully improved by controlling these
parameters. The maximum heat transfer rate was
observed at 42,000 Reynolds number, 3.417 Sy/D
and 100 mm fin height.
(e) The most effective parameter on the friction
factor was found to be fin height. The minimum
friction factor was observed at 100 mm fin height,
42,000 Reynolds Number and 3.417 pitch
(f) When all the goals were taken into account
together, the trade-off among goals was
considered and the optimum results were obtained
at 42,000 Reynolds number, 100 mm fin height
and 3.417 Sy/D pitch.
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