A Numerical Study on the Melting Behaviors of Paraffin with and without $Al_2O_3$ Nanoparticles

One of the most effective methods of thermal energy storage is the use of Phase Change Materials (PCM). Paraffin, which is among the organic PCMs, is frequently used in thermal storage applications due to its easy accessibility and high heat storage capacity. However, it significantly limits the thermal charge / discharge (melting / solidification) rate of systems caused by their low thermal conductivity. There are many methods applied to enhance the thermal conductivity of paraffin. In this research, the melting processes of pure paraffin (Rubitherm RT50) and paraffin containing 10% $Al_2O_3$ nanoparticle in a rectangular melting area were numerically investigated. For comparison, the effect of increasing the wall temperature of the rectangular area to 65 ° C, 70 ° C and 75 ° C on the total melting time was investigated for both pure paraffin (melting temperature 50 ° C) and paraffin with nanoparticle additives. In this study, in which the Computational Fluid Dynamics (CFD) approach was used, ANSYS Fluent software was used to perform numerical analysis. Consequently it was determined that the use of $Al_2O_3$ nanoparticles improved the rate of paraffin heat transfer.

$Al_2O_3$ Nanopartiküllü ve Nanopartikülsüz Parafinin Erime Davranışları Üzerine Sayısal Bir Çalışma

Faz Değiştiren Malzemelerin (FDM) kullanımı ısıl enerji depolamadaki en verimli yöntemlerden biridir. Organik FDM’ler arasında olan parafin, kolay ulaşılabilir olması ve yüksek ısı depolama kapasitelerine sahip olması sebebiyle ısıl depolama uygulamalarında sıklıkla kullanılmaktadır. Ancak düşük ısıl iletkenlikleri sebebiyle sistemlerin ısıl şarj/deşarj (erime/katılaşma) hızını önemli ölçüde sınırlamaktadır. Parafinin ısıl iletkenliğini arttırmak amacıyla uygulanan birçok yöntem bulunmaktadır. Bu çalışmada dikdörtgen bir erime alanı içinde saf parafin (Rubitherm RT50) ve kütlece %10 $Al_2O_3$ nanopartikül katkılı parafinin erime süreçleri sayısal olarak araştırılmıştır. Karşılaştırma yapabilmek için, hem erime sıcaklığı 50 °C olan saf parafin hem de nanopartikül katkılı parafin için dikdörtgen alanın duvar sıcaklığının 65 °C, 70 °C ve 75 °C’ye arttırılmasının toplam erime zamanına etkisi incelenmiştir. Hesaplamalı Akışkanlar Dinamiği (HAD) yaklaşımının kullanıldığı bu çalışmada, sayısal analizleri yapmak için ANSYS Fluent yazılımı kullanılmıştır Çalışma sonucunda $Al_2O_3$ nanopartikül kullanımının parafinin ısı transfer hızını arttırdığı tespit edilmiştir.

PDF

___

[1] Carmona M., Bastos A. P. and García J. D., “Experimental evaluation of a hybrid photovoltaic and thermal solar energy collector with integrated phase change material (PVT-PCM) in comparison with a traditional photovoltaic (PV) module”, Renewable Energy, 172: 680-696, (2021).

[2] Tao Y. B. and He Y. L., “A review of phase change material and performance enhancement method for latent heat storage system”, Renewable and Sustainable Energy Reviews, 93: 245–259, (2018).

[3] Velmurugan K., Kumarasamy S., Wongwuttanasatian T. and Seithtanabutara V., “Review of PCM types and suggestions for an applicable cascaded PCM for passive PV module cooling under tropical climate conditions”, Journal of Cleaner Production, 293: 126065, (2021).

[4] Sari A. and Karaipekli A., “Preparation, thermal properties and thermal reliability of capric acid/expanded perlite composite for thermal energy storage”, Materials Chemistry and Physics., 109(2–3): 459–464, (2008).

[5] Habib N. A., Ali A. J., Chaichan M. T. and Kareem M., “Carbon nanotubes/paraffin wax nanocomposite for improving the performance of a solar air heating system”, Thermal Science and Engineering Progress, 23: 100877, (2021).

[6] Wu X., Gao M., Wang K., Wang Q., Cheng C., Zhu Y., Zhang F. and Zhang Q., “Experimental study of the thermal properties of a homogeneous dispersion system of a paraffin-based composite phase change materials”, Journal of Energy Storage, 36: 102398, (2021).

[7] Bazri S., Badruddin I. A., Naghavi M. S. and Bahiraei M., “A review of numerical studies on solar collectors integrated with latent heat storage systems employing fins or nanoparticles”, Renewable Energy, 118: 761- 778, (2018).

[8] Ho C. J. and Gao J. Y., “An experimental study on melting heat transfer of paraffin dispersed with Al2O3 nanoparticles in a vertical enclosure”, International Journal of Heat and Mass Transfer, 62: 2-8, (2013).

[9] Ho C. J. and Gao J. Y., “Preparation and thermophysical properties of nanoparticlein-paraffin emulsion as phase change material”, International Communications in Heat and Mass Transfer, 36(5): 467-470, (2009).

[10] Arasu A. V., Sasmito A. P. and Mujumdar A. S., “Numerical performance study of paraffin wax dispersed with alumina in a concentric pipe latent heat storage system”, Thermal Science, 4-4, (2012).

[11] Arasu A. V. and Mujumdar A. S., “Numerical study on melting of paraffin wax with Al2O3 in a square enclosure”, International Communications in Heat and Mass Transfer, 39: 8–16, (2012).

[12] Arasu A. V., Sasmito A. P. and Mujumdar A. S., “Thermal performance enhancement of paraffin wax with Al2O3 and CuO nanoparticles – a numerical study”, Frontiers in Heat and Mass Transfer, (2011).

[13] Afshari F., Zavaragh H.G. and Di Nicola G., “Numerical analysis of ball-type turbulators in tube heat exchangers with computational fluid dynamic simulations”, International Journal of Environmental Science and Technology, 16(7): 3771-3780, (2018).

[14] Khanlari A., Sözen A. and Variyenli, H. İ., “Simulation and experimental analysis of heat transfer characteristics in the plate type heat exchangers using TiO2/water nanofluid”, International Journal of Numerical Methods for Heat & Fluid Flow, 29(4): 1343-1362, (2019).

[15] Naidu G. C., Aruna K., Reddy K. D. and Ramaiah P. V., “CFD simulation for charging and discharging process of thermal energy storage system using phase change material”, International Journal of Engineering Research, 5(4): 332-339, (2016).

[16] Ansys, “ANSYS Fluent theory guide”, Canonsburg: ANSYS Inc., (2017).

[17] https://www.rubitherm.eu/media/products/datasheets/T echdata_-RT50_EN_09102020.PDF

[18] Pahamli Y., Hosseini M. J., Ranjbar A. A. and Bahrampoury R., “Analysis of the effect of eccentricity and operational parameters in PCM-filled single-pass shell and tube heat exchangers”, Renewable Energy, 97: 344-357, (2016).

[19] Waghmare A., “Heat transfer enhancement by adding Al2O3 nano-material in paraffin wax for solar-thermal application”, Conference: Institution of Engineers, 38: (2014)