Heat Transfer Enhancement of Nano Al2O3 Mixed with Regular Coolant Blends in Compact Heat Exchanger
Balaji Naiak Mudavath*
| Srinivas Chandanam
© 2024 The authors. This article is published by IIETA and is licensed under the CC BY 4.0 license (http://creativecommons.org/licenses/by/4.0/).
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Heat transfer enhancement is showing a relatively positive effect on compact heat exchanger performance in automobile applications. Heat transfer enhancement helps to increase the thermal efficiency of the heat exchanger, allowing it to transfer more heat in less time. This helps to reduce the fuel consumption of the vehicle and increase its efficiency. Present researches focus on the enhancement of high-performance heat exchangers in heavy cargo vehicles in the automobile sector. Compact heat exchangers having low space occupancy and high performance coolant blends need to be studied for heat transfer applications. The work is a case study of blends comparison with and without Nano addition to check the variation after adding 1% Al2O3 to locally available coolants like TFC Anti-freeze coolant, MFC, Castrol. The experiments were run at 60℃ and 80℃ and 1.765, 3.53 bar pressure taken as full flow and pressure drop conditions. The Sonication process was also explained to evaluate the thermal properties of coolant blends before and after NANO-addition. The addition of NANO-Al2O3 with MFC gave good results when compared with the others.
heat transfer, compact heat exchanger, nano- Al2O3,coolant blends
Heat exchangers are the most necessary equipment used in automobiles, the pharma industries, and heat-absorbing and transferring applications. There are many types of heat exchangers that are available, such as shell and tube, fin tube, coil based Etc. Compact heat exchangers are better than others. CHE has common occupation space with more surface area [1]. CHE applications are known to be less space-consuming with a high heat transfer rate, such as radiators in heavy vehicles. Composites are known to be effective for heat transfer applications. The present study also explores composite plates and fins in CHE fabrication [2]. The current research also focuses on conventional water blends and NANO addition to check heat exchanger performance. Blends are added at different ratios to water to evaluate the most effective thermal properties as an approach. A test rig has been made to check the experimental analysis of all coolant blends.
Heat dissipation is probably one of the most important considerations in engine design. Internal combustion engines create enough heat to destroy themselves. Without an efficient cooling system, we wouldn't be able to do what we do today. The original radiators were simple networks of round copper dissipation. Generally, thermal fluids have poor thermophysical properties due to their inherent characteristics. As a promising solution to increase thermal energy system efficiency, Nano fluids with a stable design, enhanced heat transfer and a lower pressure drop are suggested. The effectiveness of compact heat exchangers can be enhanced by using promising new thermal fluids called ''Nano fluids'' for heat transfer and fluid flow.
The present research focused on the experimentation of Nano Al2O3 mixed with conventional coolants to improve the performance of heat exchanger by increasing heat transfer rate.
Dissipation, generally, thermal fluids have poor thermophysical properties due to their inherent characteristics. As a promising solution to increase thermal energy system efficiency, Nano fluids with a stable design, enhanced heat transfer and a lower pressure drop are suggested. The effectiveness of compact heat exchangers can be enhanced by using promising new thermal fluids called ''Nano fluids'' for heat transfer and fluid flow.
The present research focused on the experimentation of Nano Al2O3 mixed with conventional coolants to improve the performance of heat exchanger by increasing heat transfer rate.
Kim and No [3] investigated a new PCHE model's thermal-hydraulic performance using various airfoil shape fins. It was found that the new PCHE model had the same heat transfer performance and a pressure drop that was only within as large as that of the standard zigzag channel PCHE. PCHE has a low porosity of about 0.4-0.55 compared to a typical PFHE porosity range of 0.6-0.75. In comparison to traditional shell-and-and-tube heat exchangers with the same thermal duty and pressure drop, PCHEs have a volume that is 4–6 times smaller and weighs about half as much because of their compact design. In the study of Manente and Fortuna [4], a conventional internal combustion engine radiator heat transfer and pressure loss can be predicted with mathematical modeling. According to the findings, different materials, such as copper, brass, aluminum, carbon steel and stainless steel had varying effects on the building of fins and tubes. This was done by assuming that the bonding effectiveness between tubes and fins was 100 percent. Various fin and tube material combinations were tested during normal radiator operation to see how well they performed. Two different authors, two different pieces of work, performed experiments for water and airflows, respectively, in a tube-in-tube heat exchanger under iso thermal heating conditions to study the turbulent heat transfer and pressure drop characteristics of straight and helically finned tubes [5].
However, Yang et al. [6] found that in addition to physical features, the style of flow (laminar or turbulent) within the heat-exchanging equipment has a significant impact on a Nano fluid’s performance. In helical coils and parallel surfaces, Saeed and Kim [7] analyzed at the flow of Al2O3 Nano fluid. There was a significant improvement in heat transfer efficiency with increasing particle concentration for Reynolds numbers ranging from 250 to 1000. However, they found that the base fluid had a negative impact on wall shear stress. Hu et al. [8] suggested from using nanoparticles in two-phase CHE, according to the study. Particles begin to collect in rather big clusters near the tube exit once the boiling process begins because of regionalized evaporation. Once this clustering occurs, the coolant cannot get into the cooling system, and the complete cooling system fails due to catastrophic cooling system failure. Bennett and Chen [9] investigated at heat transfer and pressure drop data for straight and spiral finned tubes with fin heights ranging from 0.77 to 3.3 mm when using water as the working fluid. In terms of hydraulic diameter, the Reynolds number ranged from about 1500 to 50000. There had been an earlier laminar-to-turbulent transition, the researchers determined.
When it came to friction factor, their results showed that the smooth tube correlations could also be applied for the rugged region's tested finned tubes [10]. For sustainable growth, it is critical to produce, convert, and consume energy correctly. There are many industrial applications for heat transfer, including power generation plants, automobiles, aerospace, and chemical industries. A number of challenges emerged in this field, like improving energy efficiency and reliability for devices, as well as miniaturization (lower sizes) and cost reduction. In heat transfer applications, compact heat exchangers (CHXs) provide better thermal performance, are smaller, require less thermal fluid amount and have lower production costs. Heat transfer intensification is needed, however, when conventional thermal fluids flow through CHX minichannels for cooling/heating [11]. By dispersing metallic/non-metallic nanoparticles into conventional thermal fluids, Nano fluids have been studied by many researchers since then for applications such as cooling engine devices, managing vehicle thermal energy, renewable energy technology [12], microelectromechanical systems, medical devices, cooling energy systems, and so forth for a number of thermal applications, it was found that Nano fluids can be operated successfully with CHXs. Nonetheless, using Nano fluids may cause some problems such as corrosion in the walls of the channels, nanoparticle sedimentation and increased pressure drop by Sarafraz et al. [13]. This requires further careful investigations into the flows of Nano fluids for each nanoparticle type. So far, several studies have been conducted focusing on the heat transfer behaviours of Nano fluids flowing through several CHX types. Shell and tube heat exchangers are extensively used in numerous applications in the industrial sector, including electricity plants and oil production [14]. According to researchers in this field, Nano fluids, when flowed in the tube side of a compact shell and tube HX (inner diameter of the tube Din-tube, 8.1 mm), can improve thermal performance. Yang et al. [15] conducted an experimental investigation. On horizontal shell and tube HX working with two types of nano fluids (Al2O3/water and TiO2/water). It is under turbulent flow conditions that no fluids flow through the tube (5.1 mm in diameter). The results indicated a significant enhancement in HTC up to 20% for Al2O3 Nano fluid and up to 24% for TiO2 Nano fluid compared with base fluid at the same Peclet number. Also, Albadr [16] investigated the thermal performance of shell and tube HX with a tube of 2.4 mm diameter, moving Al2O3 Nano fluids under turbulent flow. With increasing particle concentration, thermal performance showed a significant improvement. Another study by Barzegarian et al. [17], a shell and tube HX with a 5 mm inner diameter was used to contain Al2O3 Nano fluid at several particle concentrations. When particle concentration was increased to 0.3 vol%, a significant increase in heat transfer (Nu) was observed. Munimathan et al. [18] conducted a study on heat transfer rates using Al2O3/water nanofluids at concentrations of 0.25%, 0.1%, and compared these with deionized water in microchannel heat conductors. In the study of Nakhchi and Esfahani [19], the combined effects of CuO-water nanofluids and perforated louvered strip vortex generators with various geometries on the turbulent flow characteristics inside circular tubes were numerically investigated. In the study of Zhang et al. [20], the chevron angle was identified as the most important geometrical parameter for chevron corrugation plate heat exchangers, according to the data. The pressure drop and heat transfer in single-phase systems increase as the chevron angle rises. The research of Kapustenko et al. [21] investigates heat transfer and pressure losses during different types of vapor condensation occurring in plate heat exchanger (PHE) channels. It specifically focuses on the local process parameters within small zoned areas of the channels and analyzes how these parameters are distributed across the channel field, taking into account the geometry of the grooves. Albadr et al. [22] analyzed are the heat transfer and flow properties of a water-based nanofluid containing varying volume concentrations of Al2O3 (0.2-2%) that flows counter to a horizontal shell-and-tube heat exchanger under turbulent conditions.
The present work is divided into two case studies. There was an addition of 8 and 10% of coolants to water primarily. These blends are tested when the temperatures and pressure drop up to the stagnated level of transfer at approximately 600 seconds. A second case study adds coolant to water at 8 and 10% with1% Nano addition to each percentage.
Properties evaluation: Thermal properties are evaluated for the performance study of coolant blend with experimental heat transfer data. Conventional coolants taken as primary blending with water and properties are evaluated for the first case of experiment to check the heat transfer rate after blending to water. The results were shown in the Table 1.
Table 1. Blend properties of water blends with coolants
|
Parameter |
TFC Blend |
MFC Blend |
Castrol Blend |
|||
|
|
8% |
10% |
8% |
10% |
8% |
10% |
|
Density (kg/m3) |
861 |
872 |
1028 |
1087 |
1040 |
1065 |
|
Boiling point (℃) |
120 |
121 |
135 |
145 |
112 |
123 |
|
Melting point (℃) |
70 |
70 |
70 |
70 |
104 |
104 |
|
Thermal conductivity (W/m℃) |
5.231 |
5.346 |
6.431 |
6.682 |
6.328 |
6.628 |
|
Specific heat (Kj/Kg/K) |
0.689 |
0.72 |
0.692 |
0.764 |
0.521 |
0.552 |
3.1 Preparation of blends
Blends are primarily prepared with 8 and 10% of TFC Anti-freeze coolant, MFC, Castrol added to the distilled water at room temperature to check the concentration. The addition of NANO Al2O3 particles of 1% to this blend sonicated for further properties evaluation. Nano coolant sonication equipment process has been shown in the Figure 1. The process explained below:
Figure 1. The ultrasonic both vibrator and spectrometer for sonication
All the chemical compounds used in our experiments were analytic and were used directly without further washing. Our experimental procedure has been as follows:
Stability and operational performance of Nano fluids are the major obstacles to be overcome. Thermo-physical qualities must be maintained throughout time, which necessitates nano fluid stability. Stability of nano-fluids is being improved, as is understanding of nano-fluid behaviour as part of the supply chain required to commercialise these cutting-edge fluids. Nano fluid investigations, comprising production, stability evaluative mechanisms and sweetening techniques and Nano fluid thermodynamic properties will be described in this context. There is now a strong correlation between particle dispersion uniformity and the preparation process performed. If two similar Nano fluids made in different methods have different thermophysical properties, it could have a major impact on both. The thermo - physical properties features and the tendency to aggregate could hardly be more dissimilar.
1. The distilled water (100 mL) was dissolved at room temperature and stirred by ultrasound during 10-minute sonication in some quantity of aluminium, isopropyl alcohol and PEG6000.
2. Nitric acid in an adequate volume was processed with 1.5 weight percent KH-560 for 30 minutes at 65℃ with magnetic stirring. Once the pH of the Alooh gel was reduced to 9, ammonia was added and the Al2O3 precursor was produced.
3. After washing with alcohol, the Al2O3 precursor was placed in the autoclave three times, and reaction conditions were set at 220℃, 3.6 Mpa pressure, and 2.5 hours, resulting in modified Nano particles.
4. The situ-modified methodology completes the surface preparation and adjustment for nanoparticles Al2O3 immediately.
5. The sonication did for 45 days to check the increased viscous values, thermal properties tested for Nano blends. Properties of blends shown in Table 2 after sonication with conventional coolants for the improvement of HTR.
Table 2. Blend properties of water blends with coolants with 1% NANO Al2O3 addition
|
Parameter |
TFC Blend |
MFC Blend |
Castrol Blend |
|||
|
|
8% |
10% |
8% |
10% |
8% |
10% |
|
Density (kg/m3) |
870 |
878 |
1040 |
1814 |
1040 |
1065 |
|
Boiling point (℃) |
120 |
121 |
135 |
145 |
112 |
123 |
|
Melting point (℃) |
70 |
70 |
70 |
70 |
104 |
104 |
|
Thermal conductivity (W/m℃) |
5.231 |
5.346 |
6.431 |
6.682 |
6.328 |
6.628 |
|
Specific heat (Kj/Kg/K) |
0.689 |
0.72 |
0.692 |
0.764 |
0.521 |
0.552 |
The blend properties in the two cases are characterized for further research. Coolants are tested at 600℃ and 800℃ for no pressure drop conditions and 50% pressure drop on the coolant input side. Each test runs a span of 10 minutes, that the temperature transfer gets stabilized.
Coolant blends tested for the parameters mentioned earlier of methodology to check the heat transfer difference in cold and hot side to check the coolant's performance and designed heat ex-changer performance. Experimental work has been carried out at two temperature inputs of 60 and 80 degrees with a time interval of 60 seconds, up to 10 minutes working time taken to stabilize the exact quantity of heat carried out. The temperature difference has been taken for all three blends with Nano addition. Sonication process of nano particles with blends gives a good particle distribution in the conventional coolant. The density of the coolant blend varied at minute level when the sonication done for a long time up to even distribution of particles. Experimentation done for counter flow direction for with and without Nano addition. The experimental setup to test the Nano coolant in compact heat exchanger with equipment details shown in the Figure 2.
Figure 2. The test-rig setup of compact heat exchanger
The results obtained for comparison of 60℃ hot side for 8% blend given in the Table 3.
Table 3. Comparative results of 60℃ hot side for 8% blend
|
S. No. |
Time (S) |
MFC |
TFC |
Castrol |
|
1 |
60 |
9.8 |
1.1 |
9.3 |
|
2 |
120 |
12.44 |
20.2 |
8.7 |
|
3 |
180 |
11.44 |
15.2 |
7.2 |
|
4 |
240 |
12.42 |
12.3 |
7.9 |
|
5 |
300 |
12.65 |
11 |
8.2 |
|
6 |
360 |
14.75 |
9 |
7.7 |
|
7 |
420 |
15.77 |
9.1 |
7.5 |
|
8 |
480 |
17.8 |
8.4 |
7.3 |
|
9 |
540 |
18.72 |
7.8 |
6.2 |
|
10 |
600 |
19.32 |
8.2 |
8.2 |
Comparisons made with three blends and the coolant TFC having initial rise and sudden fall with the increase of cycle time when it comes to stability, Castrol shows the consistency. Still, not much variation found on the hot liquid input side means the coolant-carrying capacity from the initial stage is quite convenient. Compared to these two at no pressure drop and at 60℃, a gradual increase in the heat absorption was found in MFC as shown in Figure 3. The full flow of the coolant substance without any disturbance with maximum capacity has been shown in Figure 3.
The comparative results at 60℃, cold side 8% coolant blend are given in the Table 4. The results showing that 8% MFC given better results compare with other coolants. The results comparison plot shown in the Figure 4.
Figure 3. Time vs temperature difference without pressure drop hot side at 60℃
Table 4. Comparative results of 60℃ cold side for 8% blend
|
S. No. |
Time S sec |
MFC |
TFC |
Castrol |
|
1 |
60 |
18.28 |
8.6 |
10.2 |
|
2 |
120 |
19.48 |
18 |
9.9 |
|
3 |
180 |
14.72 |
15.5 |
8.7 |
|
4 |
240 |
12.73 |
13.1 |
7.8 |
|
5 |
300 |
14.65 |
11.9 |
7.9 |
|
6 |
360 |
12.46 |
10.9 |
7.4 |
|
7 |
420 |
11.05 |
10.2 |
7.6 |
|
8 |
480 |
11.56 |
10 |
7.2 |
|
9 |
540 |
10.35 |
9.7 |
6.9 |
|
10 |
600 |
11.54 |
9.8 |
7.1 |
The comparison of the above graph (Figure 4) clearly shows the difference in the heat absorption rate of Castrol coolant blend after Nano addition also significantly less when compared with MFC and TFC. At the stabilized time, the cold side difference is more negligible, but the absorbing capacity of MFC is better than the other two.
Figure 4. Time vs temperature difference without pressure drop cold side at 60℃
The comparative results at 60℃ hot side for 8% coolant blend are given in the Table 5. The results showing that 8% MFC given better results at 50% pressure drop also compare with other coolants. The results comparison plot shown in the Figure 5.
In the pressure drop condition, MFC shows a significant difference while the Castrol and TFC have their consistency of not much variation in absorbing capacity. Graphical comparison of the above coolants showing clear temperature difference even in the pressure drop condition at the hot side; and relevant cold side should be noted within the consideration of coolant evaporation. The input pressure for the coolant to reduce mass flow rate a volve attached to the coolant input side to test the half capacity of tank level when coolant level at low condition.
Table 5. Comparative results of 60℃ with 50% pressure drop hot side for 8% blend
|
S. No. |
Time S sec |
MFC |
TFC |
Castrol |
|
1 |
60 |
6.8 |
0.5 |
6.9 |
|
2 |
120 |
9.4 |
10.5 |
7 |
|
3 |
180 |
11.18 |
9.8 |
7 |
|
4 |
240 |
11.75 |
9.2 |
7 |
|
5 |
300 |
13.65 |
8.9 |
6.7 |
|
6 |
360 |
13.75 |
8.6 |
6.6 |
|
7 |
420 |
16.77 |
8.2 |
5.6 |
|
8 |
480 |
17.79 |
8 |
6.3 |
|
9 |
540 |
18.15 |
7.9 |
6.4 |
|
10 |
600 |
19.32 |
7.6 |
6.3 |
Figure 5. Time vs temperature difference with pressure drop hot side at 60℃
The comparative results at 60℃ cold side 8% coolant blend are given in the Table 6. The results showing that 8% MFC given better results at 50% pressure drop also compare with other coolants. The results comparison plot shown in the Figure 6.
Table 6. Comparative results of 60℃ with 50% pressure drop cold side for 8% blend
|
S. No. |
Time S sec |
MFC |
TFC |
Castrol |
|
1 |
60 |
14.7 |
8.5 |
6.8 |
|
2 |
120 |
17.16 |
11.8 |
7.2 |
|
3 |
180 |
18.06 |
10.8 |
6.8 |
|
4 |
240 |
19.85 |
10.1 |
6.6 |
|
5 |
300 |
21.85 |
10 |
7 |
|
6 |
360 |
22.8 |
9.9 |
6.7 |
|
7 |
420 |
23.35 |
9.9 |
6.9 |
|
8 |
480 |
25.1 |
9.7 |
6.5 |
|
9 |
540 |
25.1 |
9.5 |
6.5 |
|
10 |
600 |
16.73 |
9.2 |
6.2 |
As observed from the comparison at graph 3, graph four also followed concerning MFC has given significant variation at the above temperature of 60℃ in pressure drop condition. Castrol made an equal variation, and TFC was consistent, but the difference in heat-absorbing capacity is low.
The comparative results at 80℃, hot side 8% coolant blend are given in the Table 7. The results showing that 8% MFC given better results compare with other coolants. The results comparison plot show in the Figure 7.
Figure 6. Time vs temperature difference with pressure drop cold side at 60℃
Table 7. Comparative results of 800℃ hot side for 8% blend
|
S. No. |
Time S sec |
MFC |
TFC |
Castrol |
|
1 |
60 |
21 |
1.2 |
21.4 |
|
2 |
120 |
24.89 |
18.1 |
17.1 |
|
3 |
180 |
24.88 |
16.2 |
14.2 |
|
4 |
240 |
22.79 |
13.7 |
12.5 |
|
5 |
300 |
22.64 |
12.6 |
11.1 |
|
6 |
360 |
22.22 |
11.7 |
11.1 |
|
7 |
420 |
22.72 |
10.9 |
9.9 |
|
8 |
480 |
23.11 |
11.1 |
10 |
|
9 |
540 |
23.11 |
10.1 |
9.1 |
|
10 |
600 |
22.88 |
10.3 |
9.1 |
The temperature raised to 80 degrees in the second case means the input of the hot side increases to check the performance of Nano coolant with the above three blends. At increased temperatures, heat absorption capacity also increased in all the coolants. In the perception of consistency, all the coolants are good at Nano addition, but MFC given more variation in heat-absorbing capacity, the difference rate is more than 20 degrees.
The comparative results at 80℃, cold side 8% coolant blend are given in the Table 8. The results showing that 8% MFC given better results compare with other coolants. The results comparison plot show in the Figure 8.
Figure 7. Time vs temperature difference with no pressure drop hot side at 80℃
A notable difference in heat transfer was observed on the cold side with increasing temperature in all Nano coolant blends. TFC is a bit higher than Castrol, but variation between these two is very low, compare to this, MFC increases its heat absorption rate with time which is not found in another two blends. Found an approximate variation of 20% with MFC to other Nano blends.
Table 8. Comparative results of 80℃ cold side for 8% blend
|
S. No. |
Time S sec |
MFC |
TFC |
Castrol |
|
1 |
60 |
27.8 |
7.4 |
18.2 |
|
2 |
120 |
27.57 |
16.5 |
14.7 |
|
3 |
180 |
28.18 |
15.6 |
12.6 |
|
4 |
240 |
28.19 |
13.7 |
10.8 |
|
5 |
300 |
28.62 |
13 |
10.2 |
|
6 |
360 |
29.17 |
12.2 |
9.6 |
|
7 |
420 |
29.89 |
11.6 |
9.2 |
|
8 |
480 |
30.14 |
11.7 |
9.1 |
|
9 |
540 |
31.27 |
11.5 |
8.9 |
|
10 |
600 |
32.06 |
11.2 |
8.7 |
Figure 8. Time vs temperature difference with no pressure drop cold side at 80℃
The comparative results at 80℃ hot side 8% coolant blend are given in the Table 9. The results showing that 8% MFC given better results at 50% pressure drop also compare with other coolants. The results comparison plot shown in the Figure 9.
Table 9. Comparative results of 80℃ with 50% pressure drop hot side for 8% blend
|
S. No. |
Time S sec |
MFC |
TFC |
Castrol |
|
1 |
60 |
26.9 |
1.4 |
12.8 |
|
2 |
120 |
25.3 |
23.3 |
14.9 |
|
3 |
180 |
24.2 |
17.4 |
12.5 |
|
4 |
240 |
23.1 |
15.4 |
11.2 |
|
5 |
300 |
22.1 |
12.7 |
11.2 |
|
6 |
360 |
22 |
11.4 |
10.3 |
|
7 |
420 |
20.9 |
10.3 |
10.1 |
|
8 |
480 |
21.1 |
10.2 |
9.4 |
|
9 |
540 |
20.3 |
10.2 |
10.5 |
|
10 |
600 |
20.7 |
10 |
9.6 |
Figure 9. Time vs temperature difference with pressure drop hot side with at 80℃
A differed condition observed with the comparison of the above graph the pressure drop affected the blend at high temperature. MFC noted good result along with time its noted that heat took capacity decreasing at pressure drop, variation of 10% between normal and pressure drop conditions are observed.
The comparative results at 80℃ cold side 8% coolant blend are given in the Table 10. The results showing that 8% MFC given better results at 50% pressure drop also compare with other coolants. The results comparison plot shown in the Figure 10.
Table 10. Comparative results of 80℃ with 50% pressure drop cold side for 8% blend
|
S. No. |
Time S sec |
MFC |
TFC |
Castrol |
|
1 |
60 |
24.7 |
1.6 |
8.2 |
|
2 |
120 |
22.9 |
20.8 |
14.7 |
|
3 |
180 |
21.8 |
17.1 |
12.6 |
|
4 |
240 |
21.5 |
15 |
10.2 |
|
5 |
300 |
20.4 |
12.3 |
9.6 |
|
6 |
360 |
20.6 |
12.3 |
9.2 |
|
7 |
420 |
20.1 |
11.6 |
9.2 |
|
8 |
480 |
20 |
11.3 |
9.1 |
|
9 |
540 |
19.4 |
11.2 |
8.9 |
|
10 |
600 |
19.3 |
11 |
8.7 |
Cold side is also relatively similar to the hot side at higher temperature and pressure drop graph 8 comparatively similar to hot side a clear difference of 10-12% observed between MFC and other coolant blends.
The comparative results at 60℃ hot side 10% coolant blend with Nano addition are given in the Table 11. The results showing that 10% MFC given better results at no pressure drop also compare with other coolants. The results comparison plot shown in the Figure 11.
Figure 10. Time vs temperature difference with pressure drop cold side with at 80℃
Table 11. Comparative results of 60℃ hot side for 10% blend with NANO
|
S. No. |
Time S sec |
MFC |
TFC |
Castrol |
|
1 |
60 |
10.2 |
1.4 |
9.7 |
|
2 |
120 |
12.44 |
20.3 |
8.7 |
|
3 |
180 |
11.44 |
17.2 |
7.9 |
|
4 |
240 |
12.42 |
15.3 |
7.11 |
|
5 |
300 |
12.65 |
3.2 |
8.22 |
|
6 |
360 |
14.75 |
9.2 |
7.12 |
|
7 |
420 |
15.77 |
9.4 |
7.52 |
|
8 |
480 |
17.81 |
8.8 |
7.3 |
|
9 |
540 |
18.88 |
7.9 |
6.2 |
|
10 |
600 |
20.33 |
8.5 |
8.2 |
Figure 11. Time vs temperature difference with no pressure drop hot side with at 60℃
From the comparative analysis, after increasing to10% blend addition with 1% Nano Al2O3. The results are pretty increased in the temperature difference value of input and output as properties deviated with coolant. A 5-8% raise in differential values compared to the previous experiment of 8% blend.
The comparative results at 60℃ cold side 10% coolant blend with Nano addition are given in the Table 12. The results showing that 10% MFC given better results at no pressure drop also compare with other coolants. The results comparison plot shown in the Figure 12.
Table 12. Comparative results of 60℃ cold side 10% blend with NANO
|
S. No |
Time S sec |
MFC |
TFC |
Castrol |
|
1 |
60 |
18.30 |
9.62 |
10.11 |
|
2 |
120 |
20.52 |
20.5 |
9.11 |
|
3 |
180 |
14.88 |
18.5 |
12.4 |
|
4 |
240 |
12.75 |
19.12 |
11.8 |
|
5 |
300 |
14.68 |
12.92 |
10.7 |
|
6 |
360 |
11.49 |
13.98 |
8.9 |
|
7 |
420 |
12.15 |
15.25 |
8.74 |
|
8 |
480 |
12.62 |
12.45 |
8.17 |
|
9 |
540 |
12.37 |
10.78 |
9.14 |
|
10 |
600 |
12.58 |
10.82 |
7.19 |
Figure 12. Time vs temperature difference with no pressure drop cold side with at 60℃
At cold side comparison, the blends increased their capacity to absorb heat when coming to stable absorption, except MFC other blends are not much preferable at the cold end. Slight differences are observed in all the combinations compare with the 8% blend.
The comparative results at 60℃ hot side 10% coolant blend with Nano addition are given in the Table 13. The results showing that 10% MFC given better results at 50% pressure drop also compare with other coolants. The results comparison plot shown in the Figure 13.
Table 13. Comparative results of 60℃ with 50% pressure drop hot side 10% blend with NANO
|
S. No. |
Time S sec |
MFC |
TFC |
Castrol |
|
1 |
60 |
7.12 |
1.0 |
8.9 |
|
2 |
120 |
10.4 |
12.52 |
9.8 |
|
3 |
180 |
12.18 |
10.8 |
9.15 |
|
4 |
240 |
12.75 |
10.22 |
9.14 |
|
5 |
300 |
13.65 |
9.9 |
8.75 |
|
6 |
360 |
12.75 |
9.62 |
8.6 |
|
7 |
420 |
18.77 |
9.22 |
8.6 |
|
8 |
480 |
19.79 |
8.22 |
7.3 |
|
9 |
540 |
20.15 |
8.92 |
7.4 |
|
10 |
600 |
19.88 |
8.62 |
6.3 |
Much difference varied in the hot side with MFC at an initial temperature of constant input 60℃; minimal deviations were found in the other two coolant blends.
The comparative results at 60℃ cold side 10% coolant blend with Nano addition are given in the Table 14. The results showing that 10% MFC given better results at 50% pressure drop also compare with other coolants. The results comparison plot shown in the Figure 14.
Figure 13. Time vs temperature difference with pressure drop hot side at 60℃
Table 14. Comparative results of 60℃ with 50% pressure drop cold side 10% blend with NANO
|
S. No. |
Time S sec |
MFC |
TFC |
Castrol |
|
1 |
60 |
16.72 |
10.51 |
14.8 |
|
2 |
120 |
19.18 |
12.8 |
8.28 |
|
3 |
180 |
20.06 |
14.8 |
10.8 |
|
4 |
240 |
21.85 |
14.1 |
9.65 |
|
5 |
300 |
22.85 |
15 |
7.82 |
|
6 |
360 |
25.82 |
12.9 |
10.7 |
|
7 |
420 |
25.35 |
12.9 |
12.9 |
|
8 |
480 |
28.1 |
12.7 |
10.5 |
|
9 |
540 |
28.1 |
12.5 |
9.52 |
|
10 |
600 |
20.02 |
12.2 |
8.22 |
Figure 14. Time vs temperature difference with pressure drop cold side with at 60℃
Cold side with pressure drop, the evaporation of the blend becomes slow after 2% addition to the coolant blend of 8%. Castrol 10% is also consistent in addition to the extra coolant. MFC and TFC blend evaporation is also less.
The comparative results at 80℃ hot side 10% coolant blend with Nano addition are given in the Table 15. The results showing that 10% MFC given better results at no pressure drop also compare with other coolants. The results comparison plot shown in the Figure 15.
MFC has given a better result of 15% compared with the other coolant blends; the observed effects of Castrol are also similar to TFC at high temperatures.
The comparative results at 80℃, cold side 10% coolant blend with Nano addition are given in the Table 16. The results showing that 10% MFC given better results at no pressure drop also compare with other coolants. The results comparison plot shown in the Figure 16.
Table 15. Comparative results of 80℃ hot side 10% blend with NANO
|
S. No. |
Time S sec |
MFC |
TFC |
Castrol |
|
1 |
60 |
27.82 |
10.2 |
20.2 |
|
2 |
120 |
27.58 |
18.52 |
18.7 |
|
3 |
180 |
28.19 |
16.61 |
16.6 |
|
4 |
240 |
28.19 |
14.7 |
11.8 |
|
5 |
300 |
28.65 |
14.7 |
17.2 |
|
6 |
360 |
29.17 |
14.22 |
10.6 |
|
7 |
420 |
29.89 |
10.61 |
11.2 |
|
8 |
480 |
30.14 |
10.71 |
8.1 |
|
9 |
540 |
31.27 |
10.51 |
9.9 |
|
10 |
600 |
32.06 |
10.21 |
10.7 |
Figure 15. Time vs temperature difference with no pressure drop hot side with at 80℃
Table 16. Comparative results of 80℃ cold side 10% blend with NANO
|
S. No. |
Time S sec |
MFC |
TFC |
Castrol |
|
1 |
60 |
25.22 |
2.28 |
21.47 |
|
2 |
120 |
24.89 |
20.1 |
17.17 |
|
3 |
180 |
24.88 |
18.2 |
14.24 |
|
4 |
240 |
23.79 |
14.7 |
12.55 |
|
5 |
300 |
21.67 |
12.6 |
11.15 |
|
6 |
360 |
21.22 |
11.7 |
11.12 |
|
7 |
420 |
21.70 |
12.9 |
9.91 |
|
8 |
480 |
23.11 |
10.1 |
10.22 |
|
9 |
540 |
23.11 |
11.1 |
9.15 |
|
10 |
600 |
25.80 |
12.3 |
9.55 |
Figure 16. Time vs temperature difference with no pressure drop cold side with at 80℃
MFC noted good result along with time it’s noted that heat took capacity without pressure drop, variation of 15% between other coolants are observed.
The comparative results at 80℃ hot side 10% coolant blend with Nano addition are given in the Table 17. The results showing that 10% MFC given better results at 50% pressure drop also compare with other coolants. The results comparison plot shown in the Figure 17.
Table 17. Comparative results of 80℃ with 50% pressure drop hot side
|
S. No |
Time S sec |
MFC |
TFC |
Castrol |
|
1 |
60 |
28.92 |
2.42 |
12.82 |
|
2 |
120 |
28.32 |
23.3 |
14.92 |
|
3 |
180 |
25.21 |
17.4 |
12.55 |
|
4 |
240 |
24.15 |
15.4 |
11.25 |
|
5 |
300 |
23.15 |
13.7 |
11.2 |
|
6 |
360 |
23.55 |
12.4 |
12.34 |
|
7 |
420 |
20.98 |
11.35 |
12.18 |
|
8 |
480 |
21.15 |
11.22 |
11.4 |
|
9 |
540 |
20.32 |
10.24 |
12.5 |
|
10 |
600 |
20.78 |
10.55 |
10.8 |
MFC noted good result along with time it’s noted that heat took capacity decreasing at pressure drop, variation of 10% between normal and pressure drop conditions are observed. Even though the results obtained are better than 8% addition, the uniqueness observed is like another temperature with MFC compared with other coolants.
The comparative results at 80℃ cold side 10% coolant blend with Nano addition are given in the Table 18. The results showing that 10% MFC given better results at 50% pressure drop also compare with other coolants. The results comparison plot shown in the Figure 18.
Figure 17. Time vs temperature difference with pressure drop hot side with at 80℃
Table 18. Comparative results of 80℃ with 50% pressure drop cold side
|
S. No. |
Time S sec |
MFC |
TFC |
Castrol |
|
1 |
60 |
28.7 |
3.68 |
12.22 |
|
2 |
120 |
25.9 |
18.25 |
18.74 |
|
3 |
180 |
22.8 |
19.1 |
16.61 |
|
4 |
240 |
28.5 |
15.3 |
18.21 |
|
5 |
300 |
24.4 |
13.32 |
11.61 |
|
6 |
360 |
22.6 |
12.32 |
10.21 |
|
7 |
420 |
20.18 |
12.6 |
10.21 |
|
8 |
480 |
20.8 |
12.32 |
10.12 |
|
9 |
540 |
19.4 |
14.2 |
10.92 |
|
10 |
600 |
19.32 |
11.25 |
9.72 |
A variation of 25℃ was found at the cold side with coolant increment in blend in MFC. The other two are similar to the before blend percentage. Slight variations are observed.
Figure 18. Time vs temperature difference with pressure drop cold side with at 80℃
Blending of coolants with NANO addition gives positive results. Comparison of three blends made in experiment MFC with a 10% maximum temperature variation from hot to cold observed to be more than 25%. This is likely because the addition of the NANO particles helps to reduce the heat capacity of the coolant, allowing it to absorb more heat when it's cold and release more heat when it's hot. This allows the coolant to maintain a constant temperature, resulting in more energy-efficient cooling. In comparison with TFC and Castrol blends, MFC gave better results. The two results of 2nd and 3rd blends produced similar results of variation, with an approximate difference of 15% was observed when compared with MFC. This is likely due to the fact that MFC has a higher viscosity than TFC and Castrol blends, allowing it to provide better lubrication and protection. Additionally, MFC has a higher boiling point, which helps it to resist corrosion and oxidation better than TFC and Castrol blends. A cross flow analysis obtained fruitful results with selected blends; the Q value achieved was 22.14 with the specific heat load absorbed and the calculated heat transfer of the CHE with MFC coolant. This indicates that the CHE was efficiently cooled with the MFC coolant and that the Q value was significantly higher than the cross flow without the MFC coolant. This suggests that MFC coolant is an effective cooling agent for the CHE and could be used to improve the performance of other CHEs. To ensure proper validation, an experimental investigation of the same condition and Nano fluid should be conducted along with the numerical approach. This is because an experimental approach can provide direct measurements and data that can be used to compare with the numerical results. Additionally, the experimental data can provide a deeper understanding of the physical phenomena involved in the Nano fluid system, which can help refine the numerical model. It is also important to avoid generalizations about Nano fluids because expecting a specific behaviour can result in misunderstandings. This is because there are so many variables that can affect the behaviour of Nano fluids, such as the type of nanomaterials, the concentration and size of the particles, and the temperature. By conducting an experimental investigation, it is possible to gain a better understanding of the behaviour of Nano fluids and to make more accurate predictions.
[1] Aneesh, A.M., Sharma, A., Vyas, K.N., Chaudhuri, P., Srivastava, A. (2016). Thermal-hydraulic characteristics and performance of 3D straight channel based printed circuit heat exchanger. Applied Thermal Engineering, 98: 474-482. https://doi.org/10.1016/j.applthermaleng.2015.12.046
[2] Arya, A., Sarafraz, M., Shahmiri, S., Madani, S., Nikkhah, V., Nakhjavani, S. (2018). Thermal performance analysis of a flat heat pipe working with carbon nanotube-water Nano fluid for cooling of a high heat-flux heater. Heat Mass Transfer, 54: 985-997. https://doi.org/10.1007/s00231-017-2201-6
[3] Kim, I.H., No, H.C. (2011). Thermal hydraulic performance analysis of a printed circuit heat exchanger using a helium-water test loop and numerical simulation. Applied Thermal Engineering, 31(17-18): 4064-4073. https://doi.org/10.1016/j.applthermaleng.2011.08.012
[4] Manente, G., Fortuna, F.M. (2019). Supercritical CO2 power cycles for waste heat recovery: A systematic comparison between traditional and novel layouts with dual expansion. Energy Conversion and Management, 197: 111777. https://doi.org/10.1016/j.enconman.2019.111777
[5] Milani, D., Luu, M.T., Mcnaughton, R., Abbas, A. (2017). Optimizing an advanced hybrid of solar-assisted supercritical CO2 Brayton cycle: A vital transition for low-carbon power generation industry. Energy Conversion and Management, 148: 1317-1331. https://doi.org/10.1016/j.enconman.2017.06.017
[6] Yang, Y., Li, H., Yao, M., Gao, W., Zhang, Y., Zhang, L. (2019). Investigation on the effects of narrowed channel cross-sections on the heat transfer performance of a wavy-channelled PCHE. International Journal of Heat and Mass Transfer, 135: 33-43. https://doi.org/10.1016/j.ijheatmasstransfer.2019.01.044
[7] Saeed, M., Kim, M. (2019). Thermal–hydraulic analysis of sinusoidal fin-based printed circuit heat exchangers for supercritical CO2 Brayton cycle. Energy Conversion and Management, 193: 124-139. https://doi.org/10.1016/j.enconman.2019.04.058
[8] Hu, L., Chen, D., Huang, Y., Li, L., Cao, Y., Yuan, D., Wang, J., Pan, L. (2015). Investigation on the performance of the supercritical Brayton cycle with CO2-based binary mixture as working fluid for an energy transportation system of a nuclear reactor. Energy, 89: 874-886. https://doi.org/10.1016/j.energy.2015.06.029
[9] Bennett, K., Chen, Y. (2019). A two-level Plackett-Burman non-geometric experimental design for main and two factor interaction sensitivity analysis of zigzag-channel PCHEs. Thermal Science and Engineering Progress, 11: 167-194. https://doi.org/10.1016/j.tsep.2019.03.020
[10] Nakhjavani, M., Nikkhah, V., Sarafraz, M., Shoja, S., Sarafraz, M. (2017). Green synthesis of silver nanoparticles using green tea leaves: Experimental study on the morphological, rheological and antibacterial behaviour. Heat and Mass Transfer, 53: 3201-3209. https://doi.org/10.1007/s00231-017-2065-9
[11] Nikkhah, V., Sarafraz, M., Hormozi, F. (2015). Application of spherical copper oxide (II) water nano-fluid as a potential coolant in a boiling annular heat exchanger. Chemical and Biochemical Engineering Quarterly, 29(3): 405-415. http://doi.org/10.15255/CABEQ.2014.2069
[12] Salari, E., Peyghambarzadeh, M., Sarafraz, M.M., Hormozi, F. (2016). Boiling heat transfer of alumina nano-fluids: Role of nanoparticle deposition on the boiling heat transfer coefficient. Periodica Polytechnica Chemical Engineering, 60(4): 252-258. http://doi.org/10.3311/PPch.9324
[13] Sarafraz, M., Hormozi, F., Peyghambarzadeh, S., Vaeli, N. (2015). Upward flow boiling to DI-water and CuO nano fluids inside the concentric annuli. Journal of Applied Fluid Mechanics, 8(4): 651-659. http://doi.org/10.18869/acadpub.jafm.67.223.19404
[14] Tang, H., Cui, L., Sunden, B. (2020). Optimization of fifing configurations and layouts in a printed circuit heat exchanger for supercritical liquefified natural gas near the pseudo-critical temperature. Applied Thermal Engineering, 172: 115131 https://doi.org/10.1016/j.applthermaleng.2020.115131
[15] Yang, Y., Li, H., Yao, M., Zhang, Y., Zhang, C., Zhang, L., Wu, S. (2020). Optimizing the size of a printed circuit heat exchanger by multi-objective genetic algorithm. Applied Thermal Engineering, 167: 114811. https://doi.org/10.1016/j.applthermaleng.2019.114811
[16] Albadr, J. (2019). Thermal performance of shell and tube heat exchanger using PG/water and Al2O3 nanofluid. Advances in Heat Exchangers. http://doi.org/10.5772/intechopen.80082
[17] Barzegarian, R., Aloueyan, A., Yousefi, T. (2017). Thermal performance augmentation using water based Al2O3-gamma nanofluid in a horizontal shell and tube heat exchanger under forced circulation. International Communications in Heat and Mass Transfer, 86: 52-59. https://doi.org/10.1016/j.icheatmasstransfer.2017.05.021
[18] Munimathan, A., Sathish, T., Mohanavel, V., Karthick, Alagar, Madavan, R., Subbiah, Ram, Masi, Chandran, Rajkumar, S. (2021). Investigation on heat transfer enhancement in microchannel using Al2O3/Water Nanofluids, International Journal of Photoenergy, 2021: 6680627. https://doi.org/10.1155/2021/6680627
[19] Nakhchi, M.E., Esfahani, J.A. (2020). CFD approach for two-phase CuO nanofluid flow through heat exchangers enhanced by double perforated louvered strip insert. Powder Technology. https://doi:10.1016/j.powtec.2020.04.043
[20] Zhang, J., Zhu, X., Mondejar, M.E., Haglind, F. (2019). A review of heat transfer enhancement techniques in plate heat exchangers. Renewable and Sustainable Energy Reviews, 101: 305-328. https://doi.org/10.1016/j.rser.2018.11.017
[21] Kapustenko, P., Klemeš, J.J., Arsenyeva, O., Tovazhnyanskyy, L. (2023). PHE (plate heat exchanger) for condensing duties: Recent advances and future prospects. Energies, 16(1): 524. https://doi.org/10.3390/en16010524
[22] Albadr, J., Tayal, S., Alasadi, M. (2013). Heat transfer through heat exchanger using Al2O3 nanofluid at different concentrations. Case Studies in Thermal Engineering, 1(1): 38-44. https://doi.org/10.1016/j.csite.2013.08.004
