KOMPAKT BİR ISI DEĞİŞTİRİCİSİNDE GRAFEN BAZLI NANO AKIŞKANLARIN EKSERJİ ANALİZİ

Bu çalışmada, kompakt bir ısı değiştiricide grafen bazlı nanoakışkanların ekserji analizi incelenmiştir. Taban akışkan olarak saf su kullanılarak yapılan deneylerde, hacim konsantrasyonlarının %0.01 ve %0.02’sinde grafen nano-ribon ve grafen oksit nanoakışkanlar kullanılmıştır. Deneyler 36, 40 ve 44 oC akışkan giriş sıcaklıklarında, 0.6, 0.7, 0.8 ve 0.9 m3/h kütlesel debilerde gerçekleştirilmiştir. Tüm sıcaklık ve debi değerleri için yapılan hesaplamalar sonucunda hacimce %0.01 GO nanoakışkanının ekserji verimi değerlerinin kullanılan diğer nanoakışkanların ekserji verimlerinden daha yüksek olduğu bulunmuştur. Ayrıca %0.01 GO için hesaplanan ekserji yıkım değerleri, diğer nanoakışkanlar için hesaplanan ekserji yıkım değerinden daha düşüktür. Nanoakışkanların ekserji verimlerinin, akışkan debilerinin ve ısı değiştiricinin giriş sıcaklığının artmasıyla arttığı sonucuna varılmıştır. Nanoakışkan konsantrasyonlarına göre ekserji verimleri karşılaştırıldığında, akışkan konsantrasyonunun artmasıyla ekserji verimlerinin azaldığı sonucu bulunmuştur. Nanoakışkan akış hızlarının artması ve ekserji veriminin artmasıyla ekserji yıkım değerlerinin de arttığı sonucu elde edilmiştir. Nanoakışkan konsantrasyonları ile ekserji yıkımları karşılaştırıldığında, nanoakışkan konsantrasyonunun artmasıyla ekserji yıkımlarının arttığı sonucuna varılmıştır. GO nanoakışkanın ekserji yıkımındaki artış miktarının GNR'den daha fazla olduğu belirlenmiştir.

Anahtar Kelimeler:

Ekserji, İkinci yasa analizi, Nanoakışkan, Isı değiştiricisi, Isı transferi iyileştirilmesi, Grafen.

EXERGY ANALYSIS OF GRAPHENE-BASED NANOFLUIDS IN A COMPACT HEAT EXCHANGER

In this study, the exergy analysis of graphene-based nanofluids in a compact heat exchanger is examined. In experiments using distilled water as the base fluid, graphene nano-ribbon and graphene oxide nanofluids were used at 0.01% and 0.02% of the volume concentrations. The experiments were carried out at 36, 40, and 44 oC fluid inlet temperatures and 0.6, 0.7, 0.8, and 0.9 m3/h mass flow rates. As a result of the calculations made for all temperature and flow rates, it was found that the exergy efficiency values of 0.01% by volume GO nanofluid were higher than the exergy efficiency of the other nanofluids used. Also, the exergy destruction values calculated for %0.01 GO were lower than the value of exergy destruction calculated for other nanofluids. It was concluded that the exergy efficiencies of nanofluids increased with the increase of the fluid flow rates and the inlet temperature of the heat exchanger. When the exergy efficiencies were compared according to the nanofluid concentrations, it was found that the exergy efficiencies decreased with the increase of the fluid concentration. It was examined that the exergy destruction values also increases with the increase of nanofluid flow rates, as well as exergy efficiency. When the exergy destructions were compared to the nanofluid concentrations, it was concluded that the exergy destructions increased with the increase of the nanofluid concentration. It was determined that the amount of increase in exergy destruction of GO nanofluid was higher than that of GNR.

Keywords:

Exergy, Second law analysis, Nanofluid, Heat exchanger, Improving heat transfer, Graphene.,

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Ahammed N., Asirvatham G. L., and Wongwises S., 2016, Entropy Generation Analysis of Graphene–Alumina Hybrid Nanofluid in Multiport Minichannel Heat Exchanger Coupled with Thermoelectric Cooler, International Journal of Heat and Mass Transfer, 103, 1084-1097.
Baby T. T. and Ramaprabhu S., 2011, Enhanced Convective Heat Transfer Using Graphene Dispersed Nanofluids, Nanoscale Res. Lett., 6, 1-9.
Bahiraei M. and Mazaheri N., A Comprehensive Analysis for Second Law Attributes of Spiral Heat Exchanger Operating with Nanofluid Using Two-Phase Mixture Model: Exergy Destruction Minimization Attitude, Advanced Powder Technology, 32, 211-224.
Bahiraei M., Jamshidmofid M., Amani M. and Barzegarian, R., 2018, Investigating Exergy Destruction And Entropy Generation for Flow of a New Nanofluid Containing Graphene–Silver Nanocomposite in a Micro Heat Exchanger Considering Viscous Dissipation, Powder Technology, 336, 298-310.
Çalışkan H. and Hepbaşlı A., 2013, Isı Değiştiricilerinin Ekserjetik Yönleri, Mühendis ve Makina, 54, 645, 28-37.
Dincer I. and Rosen M. A., 2012, Exergy: Energy, Environment And Sustainable Development, Elsevier Science.
Dizaji H. S., Khalilarya S., Jafarmadar S., Hashemian M. and Khezri M., 2016, A comprehensive second law analysis for tube-in-tube helically coiled heat exchangers, Experimental Thermal and Fluid Science, 76, 118-125. Esfahani M. R. and Languri E. M., 2017, Exergy Analysis of a Shell-and-tube Heat Exchanger Using Graphene Oxide Nanofluids, Experimental Thermal and Fluid Science, 83, 100-106.
Fard M. G., Talaie M. R. and Nasr, S., 2011, Numerical and Experimental Investigation of Heat Transfer of Zno/Water Nanofluid in The Concentric Tube and Plate Heat Exchangers, Thermal Science, 15:1, 183-194.
Gamal M., Radwan M. S., Elgizawy I. G. and Shedid M. H., 2021, Heat Transfer Performance and Exergy Analyses of MgO and ZnO Nanofluids Using Water/Ethylene Glycol Mixture as Base Fluid, Numerical Heat Transfer, Part A: Applications, 80:12, 597-616.
Hajjar Z., Rashidi A. M. and Ghozatloo A., 2014, Enhanced Thermal Conductivities of Graphene Oxide Nanofluids, Int. Commun. Heat Mass Transfer, 57, 28-131.
Hepbasli A., 2008, A Key Review on Exergetic Analysis and Assesment of Renewable Energy Resources for a Sustainable Future, Renewable and Sustainable Energy Reviews, 12, 593-661.
Holman J. P., 2011, Experimental methods for engineers, 7th edition, Mcgraw-hill, New York.
Hung Y. H., Teng T. P., Teng T. C. and Chena J. H., 2012, Assessment of Heat Dissipation Performance for Nanofluid, Applied Thermal Engineering, 32, 132-140.
Ipek O., Kılıç B. and Gürel B., 2017, Experimental Investigation of Exergy Loss Analysis in Newly Designed Compact Heat Exchangers, Energy, 124, 330-335.
Javadi F. S., Sadeghipour S., Saidur R., Boroumandjazi G., Rahmati B., Elias M. M. and Sohel M. R., 2013, The Effects of Nanofluid on Thermophysical Properties and Heat Transfer Characteristics of a Plate Heat Exchanger, International Communications in Heat and Mass Transfer, 44, 58-63.
Jils J. and Jesseela S., 2021, Exergy Analysis in a Minichannel with Nanofluid, The International Conference on Emerging Trends in Engineering, Kozhikode, Kerala, India.
Karabulut K., Buyruk E. and Kılınç F., 2020, Experimental and Numerical Investigation of Convection Heat Transfer in a Circular Copper Tube Using Graphene Oxide Nanofluid, Journal of the Brazilian Society of Mechanical Sciences and Engineering, 42:230, 1-16.
Khairul M. A., Alima M. A., Mahbubul I. M., Saidur R., Hepbasli A. and Hossaina A., 2014, Heat Transfer Performance and Exergy Analyses of a Corrugated Plate Heat Exchanger Using Metal Oxide Nanofluids, International Communications in Heat and Mass Transfer, 50, 8-14. Khaleduzzaman S. S., Sohel M. R., Saidur R., Mahbubul I. M., Shahrul I. M., Akash B. A. and Selvaraj J., 2014, Energy and Exergy Analysis of Alumina–Water Nanofluid for an Electronic Liquid Cooling System, International Communications in Heat and Mass Transfer, 57,118-127.
Khanafer K. and Vafai K., 2011, A Critical Synthesis of Thermophysical Characteristics of Nano-Fluids, Int. Journal of Heat and Mass Transfer, 54, 4410-4428.
Kılınç F., 2015, Enhancement of Heat Transfer Performance by Using Nanofluids in Auto Radiators, Ph.D. Thesis, Cumhuriyet University, Sivas, Turkey.
Kılınç F., Buyruk E. and Karabulut K., 2020, Experimental Investigation of Cooling Performance with Graphene Based Nano Fluids in a Vehicle Radiator, Heat and Mass Transfer, 56:2, 521-530.
Lomascolo M., Colangelo G., Milanese M. and Risi A. 2015, Review of Heat Transfer in Nanofluids, Conductive, Convective and Radiative Experimental Results, Renew. Sustain. Energy, 43,1182-1198.
Maddah H., Ghasemi N., Keyvani B. and Cheraghali R., 2017, Experimental and Numerical Study of Nanofluid in Heat Exchanger Fitted by Modified Twisted Tape: Exergy Analysis and ANN Prediction Model, Heat and Mass Transfer, 53:4, 1413-1423.
Novoselov K., Geim A. K., Morozov S., Jiang D., Grigorieva M. K. I., Dubonos S. and Firsov A., 2005, Two-dimensional Gas of Massless Dirac Fermions in Graphene, Nature, 438, 197-200.
Pak B. C. and Cho Y. I., 1998, Hydrodynamic and Heat Transfer Study of Dispersed Fluids with Submicron Metallic Oxide Particles, Experimental Heat Transfer, 11,151-170.
Pandey S. D. and Nema V. K., 2012, Experimental Analysis of Heat Transfer and Friction Factor of Nanofluid as a Coolant in a Corrugated Plate Heat Exchanger, Experimental Thermal and Fluid Science, 38, 248-256.
Pandya N. S., Shah H., Molana M. and Tiwari A. K., 2020, Heat Transfer Enhancement with Nanofluids in Plate Heat Exchangers: A Comprehensive Review, European Journal of Mechanics / B Fluids, 81, 173-190.
Pantzali M. N., Kanaris A. G., Antoniadis K. D., Mouza A. A. and Paras S. V., 2009, Effect of Nanofluids on the Performance of a Miniature Plate Heat Exchanger with Modulated Surface, International Journal of Heat and Fluid Flow, 30, 691-699.
Peyghambarzadeh S. M., Hashemabadi S. H., Hoseini S. M. and Jamnani M. S., 2011, Experimental Study of Heat Transfer Enhancement Using Water/Ethylene Glycol Based Nanofluids as a New Coolant for Car Radiators, International Communications in Heat and Mass Transfer, 38, 1283-1290.
Rosen M. A., 2002, Assessing Energy Technologies and Environmental Impacts with the Principles of Thermodynamics, Applied Energy, 72, 427-441.
Sadeghinezhad E., Mehrali M., Saidur R., Latibari S. T., Akhiani A. R. and Metselaar H. S. C., 2016, A Comprehensive Review on Graphene Nanofluids, Recent Research, Development and Applications, Energy Convers. Manage., 111, 466-487.
Saleh B. and Sundar L. S., 2021, Experimental Study on Heat Transfer, Friction Factor, Entropy and Exergy Efficiency Analyses of a Corrugated Plate Heat Exchanger Using Ni/Water Nanofluids, International Journal of Thermal Sciences, 165, 106935.
Singh S. K. and Sarkar J., 2018, Energy, Exergy and Economic Assessments of Shell and Tube Condenser Using Hybrid Nanofluid as Coolant, International Communications in Heat and Mass Transfer, 98, 41-48.
Singh V., Joung D., Zhai L., Das S., Khondaker S. and Seal S., 2012, Graphene Based Materials: Past, Present And Future, Prog. Mater. Sci., 56, 1178-1271.
Sun B., Peng C., Zuo R., Yang D. and Li H., 2016, Investigation on the Flow and Convective Heat Transfer Characteristics of Nanofluids in the Plate Heat Exchanger, Experimental Thermal and Fluid Science, 76, 75-86.
Uygun C. Z., 2019, Exergy analysis by used graphen based nanofluid in car radiator, BSc. Thesis, Sivas Cumhuriyet University, Sivas, Turkey.
Vajjha R. S., Das D. K. and Namburu P. K., 2010, Numerical Study of Fluid Dynamic and Heat Transfer Performance of Al2O3 and CuO Nanofluids in the Flat Tubes of a Radiator, International Journal of Heat and Fluid Flow, 31, 613-621.
Wang Z., Han F., Ji Y. and Li W., 2020, Performance and Exergy Transfer Analysis of Heat Exchangers with Graphene Nanofluids in Seawater Source Marine Heat Pump System, Energies, 13 (7), 1762.
Wang Z., Wu Z., Han F., Wadsö L. and Sundén B., 2018, Experimental Comparative Evaluation of a Graphene Nanofluid Coolant in Miniature Plate Heat Exchanger, International Journal of Thermal Sciences, 130,148-156.
Yu W., Xie H., Wang X. and Wang X., 2011, Significant Thermal Conductivity Enhancement for Nanofluids Containing Graphene Nanosheets, Phys. Lett. A, 375, 1323-1328.