 Open Access
 Total Downloads : 36
 Authors : Manish Singla , Maheep Singh , Manmohan Singh
 Paper ID : IJERTV8IS080200
 Volume & Issue : Volume 08, Issue 08 (August 2019)
 Published (First Online): 02092019
 ISSN (Online) : 22780181
 Publisher Name : IJERT
 License: This work is licensed under a Creative Commons Attribution 4.0 International License
Comparison of Al203 and Tio2 NanoFluids for Enhancing the Cooling Performance of an Automobile Radiator
Manish Singla1, Manmohan Singp , Maheep Singp Chitkara university
Abstract: This paper aims to compare the efficiency of cooling rate of the coolants of an automobile radiator. The Nanocoolant 1 is made by using Nanoparticles Al203 and Ti02 in distilled water and the 2 is made by using Ti02 Nanoparticles in distilled water. These Nanocoolants increase the heat transfer coefficient and Nusselt number and thus helps in increasing the heat transfer rate at a particular flow rate and at a specific concentration. Increasing these parameters increases the efficiency of the radiator and prevents engine from unwanted processes like knocking, engine overhauling and preignition of fuel etc.

INTRODUCTION
Nowadays the problems related to overheating of the engine increases which reduces the performance and hence life of an engine due to the processes like knocking, preignition of fuel, overhauling of engine etc [1]. To solve this problem, an effective cooling of the engine is necessary which is not possible with the traditional coolant which is water. An experiment has been performed to find the optimum flow rate and concentration of Nanocoolant in water at which most heat will be absorbed by the coolant via convection and conduction [2] phenomenon.

SOLUTION PROPOSED
The proposed solution discloses an improved results in heat transfer coefficient, Nusselt number and also the Reynolds number. To increase these parameters, two things need to be found. One is the optimum flow rate of the Nanocoolant [3] and another one is the best concentration of Nanoparticles in distilled water. This is found by performing an experiment in which rig is made by using an automobile radiator 1200cc enclosed in GI sheet duct of 18 gauge [4]. To flow the coolant in the duct of radiator, a centrifugal pump is installed. A thermometer is used to check the temperature of the coolant. An agitator has been employed to make homogeneous solution [5] of Nano particles in water. PT100 [6] sensors has been used to check the temperatures at different places of the radiator in order to have accurate data of temperature drop at different places of the radiator.
In the first experiment, Nanocoolant is prepared by using Al203 [6] particles in different concentrations (0.10%, 0.15% and 0.2%) with the distilled water. The flow rates have been changed from 25 l/min. of the coolant in the radiator and concentrations have been varied from 0.10% to 0.20% by volume. The inlet temperature of the coolant has been increased to 500c and the time taken by it cool from 50 to 30 c is noted and graphs have been plotted. On the basis of the data, Reynolds number, Nusselt number and heat transfer coefficient has been found at all concentrations and flow rates. The most efficient concentration and flow rate have been recorded.
In the 2nd experiment, rig set up is same as discussed above. Nanocoolant is changed by adding Ti02 [7] in distilled water at three different concentrations [8] (0.10%, 0.15%, and 0.2%). Flow rate [9] have been also varied from 25 L/min. The various parameters have been recorded and most efficient flow rate [10] and concentration have been found and graph is plotted.

EXPERIMENTAL SETUP
The test rig contains a battery,an automobile radiator, a duct of GI sheet of gayge 18mm, a radiator of 1000cc, a reservoir, ana immerion rod [11], flow lines,control valves, PT100 sensors and a pump[12].

EXPERIMENTAL PROCEDURE:

Firstly, the Nanocoolant is made by mixing the Nanoparticles (Al203 and Ti02) in three different volume concentrations (0.1%, 0.15%, and 0.2%) in distilled water.

The prepared Nanocoolants are then stirred with an agitator to form homogeneous mixture and then it is stored in reservoir (bucket).

The immersion rod is used to increase the temperature of the coolants initially to 500c.

The flow rate of the Nano coolants have been controlled and varied by using a control valve from 2 l/min to 5 l/min.

The Nanofluids (coolant) is then allowed to flow into the radiator which is enclosed in duct of G.I sheet of 20 gauge via flow lines.

The coolants when flows through the tubes of the radiator, cools down (temperature drop) due to forced convection and conduction processes.

The temperature drop is then recorded and the graphs have been plotted to analyze the heat transfer rate of the coolant 1 and coolant 2.

The time taken by coolant 1 i.e. (AL203+water) to cool from 500c to 300c is analyzed and the most efficient flow rate and concentration of Nanofluid is noted.

Similarly, the time taken by 2nd Nanocoolant (Tio2 +water) is recorded and its concentration and flow rate at which maximum heat is dissipated is noted.

The heat dissipation time of both the coolants is noted at different concentrations and flow rates and thus compared to achieve most efficient results.
5. EXPERIMENTAL CALCULATIONS:
The various parameters required to perform an experiment such as Reynolds number, heat transfer coefficient and Nusselt number are calculated by using the formulas discussed below

Density of the Nanofluid (nf) is calculated by using the given formula:
nf = p + (1 )w (1)
Where
w = density of water (1000kg/m3)
p = density of Al2O3 (3900 kg/m3) f
= Nano Fluid volume concentration % (at three different values i.e. 0.1%, 0.15% and 0.2%) nf = density of Nano fluid (kg/m3)

Now, the specific heat capacity of the Nano coolant is calculated as:
(2)
Where
Cnf = specific heat capacity of the Nano coolant (J/Kgk) Cw = Specific heat capacity of water (4180 J/kgk)
Cp = Specific heat capacity of Al2O3 (880 J/kgk)

The heat transfer rate is calculated as by given equation:
Q = ( ) (3)
Where, m = mass flow rate [13] of the Nanocoolant (Kg/min) Tin= Inlet temperature (oc)
Tout= outlet temperature (oc)
Now the heat transfer coefficient is calculated by using the given equation: From Newtons law of cooling:
Q = hA (Tb Ts) (4)
Where
Q is the heat transfer rate (watt)
h = heat transfer coefficient (/2)
A is the surface area of the tube of radiator (217cm2)
Tb is the bulk temperature (oc) which is calculated by taking the average of Tin and Tout
(5)
Ts is the average wall temperature of the radiator measured from various transverse and longitudinal locations of radiator (oc)
Where n = number of tubes (50)

Now the average Nusselt number can be calculated as:
Where Dh = hydraulic diameter of the tube and is calculated as
(6)
(7)
(8)
D and d are the width and height of radiator tube. Here d=1.8 mm; D=15.5mm.

Finally the Reynolds number can be calculated as:
Re = nf vDh / (9)
Where
nf =density of Nanofluid (kg/m3)
= dynamic viscosity of the Nano coolant (Ns/m2) v= Fluid velocity (m/s)
Dh = hydraulic diameter of the tube

OBSERVATIONS :
The analysis of the Nusselt number, Reynolds number and the heat transfer coefficient for the two Nanocoolants Al203 and Tio2 at different flow rates and different volume concentrations is shown in the tables and graphs below.
m=2.27l/m
m=3.4l/m
m=4l/m
Re
Nu
(%)
Re
Nu
(%)
Re
Nu
(%)
2804
1.91
0.2
2804
2.97
0.2
2804
3.06
0.2
3249
2.46
0.15
3249
3.822
0.15
3249
4.66
0.15
4807
1.61
0.1
4807
3.177
0.1
4807
3.5
0.10
m=2.27l/m
m=3.4l/m
m=4l/m
Re
Nu
(%)
Re
Nu
(%)
Re
Nu
(%)
2804
1.91
0.2
2804
2.97
0.2
2804
3.06
0.2
3249
2.46
0.15
3249
3.822
0.15
3249
4.66
0.15
4807
1.61
0.1
4807
3.177
0.1
4807
3.5
0.10
Table 1: The table for the calculated values of Reynolds number and Nusselt number at different flow and concentrations for Al2O3.
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
3.4 l/m
2.7 lm
4 l/m
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
3.4 l/m
2.7 lm
4 l/m
2804
3249
Re
4807
2804
3249
Re
4807
Nu
Nu
Figure 1: Graph representing the variation in Reynolds number vs. Nusselt number at different flow and concentrations for Al2O3.
The graph shows the analysis of Nusselt number and Reynolds number for Al2O3 at different flow. Nusselt number increases with Reynolds number with increasing flow. Blue line shows the lesser flow of 2.27 l/m, red shows the 3.4 l/m and green likewise shows the 4 l/m. Three points in a single curve line represents the three volume concentrations. Maximum value of Nusselt number is obtained at 0.15 %. At 0.20 % the friction factor is maximum and it decreases the Reynolds number. The friction factor at 0.15
% lesser than other concentrations. The Nusselt number at 0.10 % is lesser than 0.15 % but greater than 0.20 %.
Table 2: Comparative table for the calculated values of Reynolds number and Nusselt number at different flow and concentrations for TiO2
m=2.27 l/m
m=3.4 l/m
m=4 l/m
Re
Nu
(%)
Re
Nu
(%)
Re
Nu
(%)
2373
1.8
0.2
2373
2.3
0.2
2373
2.02
0.2
3272
2.23
0.15
3272
2.8
0.15
3272
3.36
0.15
5316
1.3
0.1
5316
3.11
0.1
5316
2.76
0.10
2.27l/m
4
3.5
3
2.5
2
1.5
1
0.5
0
2.27l/m
4
3.5
3
2.5
2
1.5
1
0.5
0
3.4l/m
4l/m
0
3.4l/m
4l/m
0
1000
1000
2000
2000
3000
Re
3000
Re
4000
4000
5000
5000
6000
6000
Nu
Nu
Figure 2: Graph representing variations in Reynolds number vs. Nusselt number at different flow and concentrations for TiO2
The graph shows the experimental results in case of TiO2 at three different flow rates and at three different volume concentrations. The values of Nusselt number for TiO2 are smaller than the Al2O3 because the viscosity of TiO2 is sharply decreases with increasing inlet temperature as compared to Al2O3 so its Reynolds number increases more than Al2O3. At 4 l/m the value of Nusselt number got decreased than 0.15 % because of increasing friction factor.
Table 3: A comparative table between Al2O3 and TiO2 for their respective flow characteristics at fixed mass flow rate of 2.27 l/m
TiO2
Al2O3
Re
Nu
(%)
Re
Nu
(%)
2373
1.8
0.2
2804
1.9
0.2
3272
2.23
0.15
3249
2.46
0.15
5316
1.3
0.1
4807
1.61
0.1
m=2.27 l/m
m=2.27 l/m
3
2.5
2
1.5
1
0.5
0
3
2.5
2
1.5
1
0.5
0
0
1000 2000
3000
Re
4000 5000 6000
0
1000 2000
3000
Re
4000 5000 6000
Nu
Nu
Figure 3: Graph between Reynolds vs. Nusselt number for Al2O3 and TiO2 at m=2.27 l/m
This graph shows the analysis of Nusselt number and Reynolds number for both Al2O3 and TiO2 at 2.27 l/m flow. This is the lesser flow in the experiments. The blue line shows the TiO2 and red line indicates the Al2O3. At starting the viscosity of the Nano particle is higher and Reynolds number is less hence the low value of the Nusselt number. The thermophysical properties of the both the Nanofluids are such that the Al2O3 shows the better results as compared to TiO2 at a particular flow of 2.27l/m.
Table 4: A comparative table between Al2O3 and TiO2 for their respective flow characteristics at fixed mass flow rate of 3.4 l/m
TiO2
Al2O3
Re
Nu
(%)
Re
Nu
(%)
2373
2.3
0.2
2804
2.97
0.2
3272
2.8
0.15
3249
3.822
0.15
5316
3.11
0.1
4807
3.177
0.1
m=3.4l/m
m=3.4l/m
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
0
1000 2000
3000
Re
4000 5000 6000
0
1000 2000
3000
Re
4000 5000 6000
Nu
Nu
Figure 4: Graph between Reynolds vs. Nusselt number for Al2O3 and TiO2 at m=3.4l/m
Fig. 4 shows the graphical representation of both Nanofluids at 3.4l/m. There are three different values at particular value of flow. At this flow the TiO2 goes linear as compared to the Al2O3. Sliding velocity of Al2O3 is more than the TiO but this factor plays less role in this flow. At this flow the agitator mixed the TiO2 as compared to the Al2O3 because of its shape and composition.
Table 5: A comparative table between Al2O3 and TiO2 for their respective flow characteristics at fixed mass flow rate of 4 l/m
TiO2
Al2O3
Re
Nu
(%)
Re
Nu
(%)
2373
2.02
0.2
2804
3.06
0.2
3272
3.36
0.15
3249
4.66
0.15
5316
2.76
0.1
4807
3.5
0.1
m=4l/m
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
m=4l/m
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
0
1000
2000 3000 4000
Axis Title
5000 6000
0
1000
2000 3000 4000
Axis Title
5000 6000
Axis Title
Axis Title
Figure 5: Graph between Reynolds vs. Nusselt number for Al2O3 and TiO2 at m=4l/m
This graph shows the best results and we can find it easy for comparison. For both Nanofluids the Al2O3 shows the best results at flow 4 l/m and the volume concentration of 0.15 %. At maximum concentration the slip velocity causes the increase in friction causes decrease the Reynolds number hence lesser value of the Nusselt number as compare to other concentrations. Agitator work well at 0.15% concentrations for both Nanofluids.
So the graphs and calculations shows that the corresponding parameters are giving better results for Al2O3 as compared to the TiO2 proving Al2O3 is better Nano coolant.

CONCLUSION:

From the table and graph of aluminum as a NanoParticle shown above, it is clear that the Nanoparticle Al203 shows better results at a flow rate of 4l/min. and 0.15% concentration by volume. The Nusselt number is greater at this particular concentration and flow rate which means its convective heat transfer rate is maximum.

The table and graph of Tio2 as a Nanoparticle shows that the heat transfer rate is maximum which is determined by nusselt number at a flow rate of 4l/min and at a concentration of 0.15% by volume.

From the tables and graphs of comparison between the Nanofluids, it is deduced that the Al203 shows better results than the Tio2 as a Nanofluid at all concentrations and flow rates.

The Nusselt number increases with the concentration and flow rate but decreases at the maximum concentration (0.2%) because the slip velocity causes increase in friction which causes the decrease in Reynolds number and the Nusselt number and thus decreases the heat transfer capacity of the Nanofluid.

By comparing the two Nanofluids it has been concluded that the Al203 dissipates heat by convection medium at a faster rate than the Tio2. Thus Al203 is better Nanofluid than the Tio2 at a flow rate of 4l/min. and at a concentration of 0.15% by volume in distilled water.
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