47 Nano Progress Research Article Nano Prog., (2021) 3(5), 47-52. DOI: 10.36686/Ariviyal.NP.2021.03.05.026 Nano Prog., (2021) 3(5), 47-52. Performance Enhancement and Effectiveness of Heat Exchangers Using MWCNT/Graphene Based Nanofluid Ajey C.P.,* a Girisha Lakshman Naik., a Malteshkumar Deshpande., a Mahanthesh M.R. a and Gururaja L. b a Department of Mechanical Engineering, PES Institute of Technology and Management, Shivamogga, Karnataka, India b Department of Mechanical Engineering, PVP Polytechnic, Bengaluru, Karnataka, India *Corresponding author E-mail address: [email protected](Ajey C.P.) Ariviyal Publishing Journals ISSN: 2582-1598 Abstract: In many engineering applications, heat exchangers are used to transfer the heat between two mediums, efforts have been made to increase thermal transfer efficiency in heat exchangers to decrease heat transfer time and improve energy effectiveness. Due to the low thermal conductivities of the heat transfer fluids, the performance enhancement and compactness of heat exchangers is not up to the mark. With the increasing requirements of current technology, new kinds of heat transfer liquids need to be developed that are more efficient in the performance of heat transfer. The present work focuses on utilizing nanofluids to check the effectiveness of heat transfer phenomenon. Research shows that adding nanoparticles to the base fluid can improve the fluid's thermal conductivity. Keywords: Heat exchangers; Nano particles; Nano Fluids Publication details Received: 24 th February 2021 Revised: 20 th April 2021 Accepted: 20 th April 2021 Published: 29 th April 2021 1. Introduction One of the significant requirements of many sectors is ultrahigh- performance cooling. Low thermal conductivity, however, is a main restriction in the development of energy efficient heat transfer liquids needed for cooling purposes. Water, oil and ethylene glycol which are currently being used as coolants are limited by their decreased thermal conductivity. Research demonstrates that adding nanoparticles to the base fluid can enhance the thermal conductivity of the fluid. But nanofluid [1] conduct during heat transfer, it is also in the early stages of growth and has not been fully investigated. Research is required to promote nanotechnology and identify applications for the heat transfer of nanoparticles/nanofluids. These are developed by dispersion of nanometer sized materials in the base liquids. The nano meter sized materials are the one which are having a dimension at nano level atleast in one direction, such as nano particles, nanofibers, nanotubes, nano sheets etc. The sort of nanoparticle used depends directly on enhancing the base fluid’s necessary property. A single nano material will not possess the required properties for the required applications. The main objective of the present work includes preparation of the nanofluids using graphene, carbon nano tube (CNT) and hybrid [2] composition of graphene and carbon nano tubes by dispersing in base fluids such as distilled water and ethylene glycol. The hybrid nanofluid is expected to produce better thermal properties compared to individual nanofluid. The prepared sample is used to determine the thermo physical properties such as density, kinematic viscosity, dynamic viscosity and specific heat. The properties obtained with nanofluid samples are compared with the results of base fluid. Performance analysis of the prepared sample is carried out using double pipe heat exchanger [3] in order to determine the heat transfer rate and effectiveness in parallel and counter flow application. The results obtained are compared with the performance of base fluid and suitable conclusions are drawn. 2. Experimental Section In order to prepare the nanofluids the graphene and carbon nano tubes are used with base fluid, the detail descriptions for the same are as indicated below. 2.1. Carbon Nano Tube Carbon nanotube [4] plays a very important role in various fields due to its excellent mechanical, thermal, electrical, chemical and optical characteristics. Carbon nanotubes are capable of effectively conducting electricity and heat therefore these can behave as metals or semiconductors even they are used in electromechanical actuators and sensors. The thermal conductivity [5] values for single-walled carbon nanotube double walled carbon nanotube and multiwalled carbon nanotube, [6] respectively, are 6000 W/mK, 3986 W/mK and 3000W/mK As per these values the very important observation that can be drawn is that, the thermal conductivity is decreasing with increase in number of wall layers.
6
Embed
N ano Progress Research Article - Ariviyal Publishing
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Performance Enhancement and Effectiveness of Heat Exchangers Using MWCNT/Graphene Based Nanofluid Ajey C.P.,*
a Girisha Lakshman Naik.,
a Malteshkumar Deshpande.,
a Mahanthesh M.R.
a and Gururaja
L.b
aDepartment of Mechanical Engineering, PES Institute of Technology and Management, Shivamogga, Karnataka, India bDepartment of Mechanical Engineering, PVP Polytechnic, Bengaluru, Karnataka, India
ISSN: 2582-1598 Abstract: In many engineering applications, heat exchangers are used to transfer the heat between two mediums, efforts have been made to increase thermal transfer efficiency in heat exchangers to decrease heat transfer time and improve energy effectiveness. Due to the low thermal conductivities of the heat transfer fluids, the performance enhancement and compactness of heat exchangers is not up to the mark. With the increasing requirements of current technology, new kinds of heat transfer liquids need to be developed that are more efficient in the performance of heat transfer. The present work focuses on utilizing nanofluids to check the effectiveness of heat transfer phenomenon. Research shows that adding nanoparticles to the base fluid can improve the fluid's thermal conductivity.
Table 6. Experimental test results for graphene nano fluid Type of flow Parallel
Parameter I II
flow rate of Hot water (m3/sec) 40×10-6 50×10-6 flow rate of Cold water (m3/sec) 50×10-6 40×10-6 Inlet Nano fluid temperature (°C)(tci) 37 37.2 Outlet Nano fluid temperature(°C)(tco) 40.7 40.8 Inlet Hot water temperature (°C)(thi) 52 52.2 Outlet Hot water temperature (°C)(tho) 47.8 48
Table 7. Experimental test results for graphene nanofluid
Type of flow Counter
Parameter I II
Hot water flow rate (m3/sec) 40×10-6 50×10-6
Cold water flow rate (m3/sec) 50×10-6 40×10-6 Inlet Nano fluid temperature (°C)(tci) 37.8 37.7 Outlet Nano fluid temperature (°C)(tco) 41.2 50.1 Inlet Hot water temperature (°C)(thi) 53.1 53.2 Outlet Hot water temperature (°C)(tho) 48.6 49.3
50
Ajey et al., Nano Progress
Nano Prog., (2021) 3(5), 47-52.
Effectiveness, ε = (thi-tho) / (thi-tci) (8)
Similarly the experimental values for CNT based nano fluid for
parallel and counter flow are as shown in Table 8 and Table 9
respectively. The values of heat transfer rate and effectiveness are as
shown in Table 10.
The hybridising effect of graphene and CNT based nano fluid
gives the following experimental results. The experimental values for
parallel and counter flow are as shown in Table 11 and Table 12
respectively. Heat transfer rate and effectiveness values are as
shown in Table 13.
In order to compare the values with the base fluid the properties
of base fluid and experimental values are considered. Table 14 and
Table 15 show the Experimental test results of distilled water for
parallel and counter flow respectively. The values of heat transfer
rate and effectiveness for the same is as shown in Table 16.
4. Results and Discussions
The feature of heat transfer is a significant phenomenon for fluid
choice. In the current work, the nano particles are mixed to form
nanofluid with two different base fluids, and various experiments are
used to determine the physical properties. The performance analysis
of individual nanofluid and hybrid nanofluid for two distinct
combinations such as parallel and counter flow is performed in a
heat exchanger. For distinct flow conditions, the rate of heat transfer
and effectiveness were analyzed.
4.1. Specific Heat
From the experiment results it is observed that the hybrid nanofluid
exhibit higher specific heat. The nanofluid using carbon nanotube
shows least specific heat value whereas the nanofluid using graphene
alone yields much better specific heat value which is near to the
value obtained using hybrid nanofluid. From the results it is
concluded that the addition of nanoparticles into the base fluid will
enhance the specific heat value.
Table 8. Experimental test results of CNT nanofluid Type of flow Parallel
Parameter I II
Hot water flow rate (m3/sec) 40×10-6 50×10-6 Cold water flow rate (m3/sec) 50×10-6 40×10-6 Inlet Nano fluid temperature (°C)(tci) 37.2 37 Outlet Nano fluid temperature (°C)(tco) 39 39.2 Inlet Hot water temperature (°C)(thi) 53 51.3 Outlet Hot water temperature (°C)(tho) 48.8 46.2
Table 9. Experimental test results of CNT nanofluid
Type of flow Counter
Parameter I II
Hot water flow rate (m3/sec) 40×10-6 50×10-6 Cold water flow rate (m3/sec) 50×10-6 40×10-6 Inlet Nano fluid temperature (°C)(tci) 37.8 38.1 Outlet Nano fluid temperature (°C)(tco) 39.6 39.3 Inlet Hot water temperature (°C) (thi) 54 52.2 Outlet Hot water temperature (°C)(tho) 48.7 46.2
Table 10. Experimental test results for CNT based nanofluid
Flow Parallel Counter
Heat Transfer Rate Q (J/s) 540.10 631.88 Effectiveness 0.266 0.327
Table 11. Experimental test results of graphene/ CNT nanofluid
Type of flow Parallel
Parameter I II
Hot water flow rate (m3/sec) 40×10-6 50×10-6 Cold water flow rate (m3/sec) 50×10-6 40×10-6 Inlet Nano fluid temperature (°C)(tci) 37.2 37.8 Outlet Nano fluid temperature (°C)(tco) 40 41.2 Inlet Hot water temperature (°C)(thi) 53 52.4 Outlet Hot water temperature (°C)(tho) 48.3 49.2
Table 12. Experimental test results of graphene /CNT nanofluid
Type of flow Counter
Parameter I II
Hot water flow rate (m3/sec) 40×10-6 50×10-6 Cold water flow rate (m3/sec) 50×10-6 40×10-6 Inlet Nano fluid temperature (°C)(tci) 37.8 38.1 Outlet Nano fluid temperature (°C)(tco) 39.6 39.2 Inlet Hot water temperature (°C) (thi) 54 52.3 Outlet Hot water temperature (°C)(tho) 49.1 50.9
Table 13. Experimental test results of graphene/CNT nanofluid
Type of Flow Parallel Counter
Heat Transfer Rate Q (J/s) 694.98 632.17 Effectiveness 0.297 0.302
Table 14. Experimental test results of Base fluid (Distilled water)
Type of flow Parallel
Parameter I II
Hot water flow rate (m3/sec) 40×10-6 50×10-6 Cold water flow rate (m3/sec) 50×10-6 40×10-6 Inlet Nano fluid temperature (°C)(tci) 31.7 31.4 Outlet Nano fluid temperature (°C)(tco) 34.5 34.7 Inlet Hot water temperature (°C)(thi) 49.6 46.5 Outlet Hot water temperature (°C)(tho) 45.3 43.8
Table 15. Experimental test results of Base fluid (Distilled water)
Type of flow Counter
Parameter I II
Hot water flow rate (m3/sec) 40×10-6 50×10-6 Cold water flow rate (m3/sec) 50×10-6 40×10-6 Inlet Nano fluid temperature (°C)(tci) 31.8 32 Outlet Nano fluid temperature (°C)(tco) 34.9 34.8 Inlet Hot water temperature (°C) (thi) 50.2 47.3 Outlet Hot water temperature (°C)(tho) 45.6 44
Table 16. Experimental test results for Base fluid (Distilled water)
Type of Flow Parallel Counter
Heat Transfer Rate Q (J/s) 653.11 709.62 Effectiveness 0.24 0.25
Fig. 3. specific heat values
51
Ajey et al., Nano Progress
Nano Prog., (2021) 3(5), 47-52.
4.2. Viscosity
The experiment is performed using the Saybolt viscometer to
determine distinct fluid viscosity. Ethylene glycol is added with
nanoparticles such as graphene and carbon nanotubes, and
nanofluids are tested for flow variation at different temperatures. To
determine viscosity, the base fluid (ethylene glycol) is also tested at
distinct temperatures and the values are compared using the graph.
From the above Fig. 4 it is noted that the kinematic viscosity for
distinct fluids reduces with increase in temperature. Kinematic
viscosity is more than all other liquids at a temperature of 30C for
ethylene glycol. The kinematic viscosity value is lowest for graphene-
based nanofluid at 30C and 80C compared to other samples. At
60C hybrid nanofluid showed least value of viscosity and CNT based
nanofluid showed higher value of kinematic viscosity at 80C
compared to other samples. From the result it can be concluded that
by the addition of CNT into the base fluid the viscosity value
increased slightly and by the addition of graphene into the base fluid
the velocity value slightly decreased.
By calculating the kinematic viscosity and density of the liquids,
the dynamic viscosity is determined. The values are plotted
graphically and compared to the suitable application fluid for heat
transfer. The values are as shown in Fig. 5. From the above chart it is
noted that with the rise in temperature, the dynamic viscosity of
distinct fluids reduces. At 30C CNT based nanofluid has the least
dynamic viscosity and ethylene glycol has the higher value. At 80C
the dynamic viscosity of graphene based nanofluid is lowest and
hybrid nanofluid has the highest value.
4.3. Heat Transfer Rate and Effectiveness
Double pipe heat exchanger is used to test the performance analysis
of nanofluid samples and base liquids. Two distinct combinations
such as parallel and counter flow are analyzed. Table 17 and Fig. 6
shows the experimental values for various fluid flow rates.
From the result it is observed that the heat transfer rate of base
fluid is enhanced by the addition of graphene and reduced by the
addition of CNT into the base fluid. The results revealed that the
effectiveness value in case of counter flow is maximum in
comparison with parallel flow. CNT based nanofluid exhibit the
higher value of effectiveness in case of counter flow arrangement.
The hybrid nanofluid exhibit highest value of effectiveness in parallel
flow arrangement. graphene based nanofluid showed increase in the
effectiveness value both in case of parallel and counter flow
arrangement compare to base fluid. The base fluid is having the least
value of effectiveness. From the result it is concluded that the
effectiveness and heat transfer rate will enhance by the addition of
nano particles into the base fluid.
5. Conclusions
The following conclusions can be drawn from the obtained results.
For the assessment of heat transfer rate and effectiveness, the
nanoparticles and the base liquids are chosen. The sonication
method prepares different samples of nanofluids and analyzes the
performance features using heat exchanger. Thermo-physical
characteristics tests are carried out on the prepared nanofluids. The
experiment findings indicate that in comparison with other
nanofluids and base liquids, the specific heat of graphene and hybrid
nanofluids is greater. The experiment concludes that base fluid's
cinematic viscosity is greater and that graphene-based nanofluid at
room temperature is smaller. Nanofluid and base fluid performance
analysis is conducted for parallel and counter flow setup with a
double pipe heat exchanger. From the outcomes, it is found that the
nanofluid based on carbon nanotube is much better than other
nanofluids and base fluid for counterflow structure. In contrast to
graphene-based nanofluid and base fluid, the hybrid nanofluid shows
much higher effectiveness for both parallel flow and counter flow
arrangements.
Fig. 4. Kinematic Viscosity values.
Fig. 5. Dynamic Viscocity values for different fluids.
Fig. 6. Effectiveness values of various fluids
Table 17. Heat transfer rate values for different fluids
Fluid
Heat Transfer Rate (J/s) Flow type
Parallel Counter
graphene based nanofluid
738.98 732.67
CNT based nanofluid
540.10 631.88
CNT + graphene based nanofluid
694.98 632.17
Distilled Water 653.11 709.62
52
Ajey et al., Nano Progress
Nano Prog., (2021) 3(5), 47-52.
Conflicts of Interest
The authors declare no conflict of interest.
References
1 Khattak M.A.; Mukhtar A.; Afaq S.K. Application of Nano-Fluids as Coolant in Heat Exchangers: A Review. J. Adv. Res. Mater. Sci., 2020, 66, 8-18. [CrossRef]
2 Sarkar J.; Ghosh P.; Adil A. A Review on Hybrid Nanofluids: Recent Research, Development and Applications. Renewable Sustainable Energy Rev., 2015, 43, 164-177. [CrossRef]
3 Sarafraz M.M.; Hormozi F.; Nikkhah V. Thermal Performance of a Counter-Current Double Pipe Heat Exchanger Working with COOH-CNT/Water Nanofluids. Exp. Therm. Fluid Sci., 2016, 78, 41-49. [CrossRef]
4 Marquis F.D.S.; Chibante L.P.F. Improving the Heat Transfer of Nanofluids and Nanolubricants with Carbon Nanotubes. Jom, 2005, 57, 32-43. [CrossRef]
5 Hwang Y.J.; Lee J.K.; Lee C.H.; Jung Y.M.; Cheong S.I.; Lee C.G.; Ku B.C.; Jang S.P. Stability and Thermal Conductivity Characteristics of Nanofluids. Thermochim. Acta, 2007, 455, 70-74. [CrossRef]
6 Huang D.; Wu Z.; Sunden B. Effects of Hybrid Nanofluid Mixture in Plate Heat Exchangers. Exp. Therm. Fluid Sci., 2016, 72, 190-196. [CrossRef]
7 Bharambe-Kushal S.; Bhide-Harshad S.; Anilkumar-Sathe. Graphene Nano-fluids, International Conference on Ideas, Impact and Innovation in Mechanical Engineering, 2017, 05. [Link]
8 Sheikholeslami M.; Ganji D.D. Nanofluid Convective Heat Transfer Using Semi Analytical and Numerical Approaches: A Review. J. Taiwan Inst. Chem. Eng., 2016, 65, 43-77. [CrossRef]
9 Ebrahimnia-Bajestan E.; Moghadam M.C.; Niazmand H.; Daungthongsuk W.; Wongwises S. Experimental and Numerical Investigation of Nanofluids Heat Transfer Characteristics for Application in Solar Heat Exchangers. Int. J. Heat Mass Transf., 2016, 92, 1041-1052. [CrossRef]
10 Bashirnezhad K.; Bazri S.; Safaei M.R.; Goodarzi M.; Dahari M.; Mahian O.; Dalkılıça A.S.; Wongwises S. Viscosity of Nanofluids: A Review of Recent Experimental Studies. Int. Commun. Heat Mass Transf., 2016, 73, 114-123. [CrossRef]
12 Hung Y.H.; Gu H.J. Multiwalled Carbon Nanotube Nanofluids Used for Heat Dissipation in Hybrid Green Energy Systems. J. Nanomater., 2014, 2014. [CrossRef]
13 Nasirzadehroshenin F.; Sadeghzadeh M.; Khadang A.; Maddah H.; Ahmadi M.H.; Sakhaeinia H.; Chen L. Modeling of Heat Transfer Performance of Carbon Nanotube Nanofluid in a Tube with Fixed Wall Temperature by using ANN–GA. Eur. Phys. J. Plus, 2020, 135, 1-20. [CrossRef]
14 Borode A.O.; Ahmed N.A.; Olubambi P.A, December. Application of Carbon-based Nanofluids in Heat Exchangers: Current Trends. In Journal of Physics: Conference Series, 1378, No. 3, p. 032061. IOP Publishing, 2019. [CrossRef]
15 Behdinan K.; Moradi-Dastjerdi R.; Safaei B.; Qin Z.; Chu F.; Hui D. Graphene and CNT Impact on Heat Transfer Response of Nanocomposite Cylinders. Nanotechnol. Rev., 2020, 9, 41-52. [CrossRef]