Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 53 1 2021 03 21 An Experimental Investigation on the Convective Heat Transfer Coefficient and Nusselt Number in Water/Carbon Nanofluid An Experimental Investigation on the Convective Heat Transfer Coefficient and Nusselt Number in Water/Carbon Nanofluid 209 220 3642 10.22060/mej.2019.16148.6289 FA Amir Hossein Shiravi Department of Mechanical Engineering, Faculty of Mechanical engineering, Jundi-Shapur University of technology, Dezful, Iran Mojtaba Shafiee Department of Chemical Engineering, Faculty of Chemical Engineering, Jundi-Shapur University of Technology, Dezful, Iran Hadis Bostani Department of Mechanical Engineering, Jundi-Shapur University of Technology, Dezful, Iran Mohammad Firoozzadeh Department of Mechanical Engineering, Faculty of Mechanical Engineering, Jundi-Shapur University of technology, Dezful, Iran Maryam Bozorgmehrian Department of Mechanical Engineering, Mechanical faculty, Jundi-Shapur University of Technology, Dezful, Iran Journal Article 2019 04 17 The heat transfer coefficient of fluid is one of the most important effective factors on the performance of fluid in the heat transfer process. Due to the higher conductive heat transfer coefficient of metals than liquids, metal particles can be used to increase the heat transfer rate of liquids. Nanofluid is one of the novels and developing methods to improve the heat transfer rate in heat exchangers. In this paper, the main effective parameters (flow rate and concentration) on increasing the convective heat transfer coefficient of water carbon nanofluid compared with water as a base fluid, are investigated in the Reynolds range of 7,100 to 16,700. The results illustrate that increasing the Re leads to increase in the Nusselt number and convective heat transfer coefficient, and also to decrease the friction factor. It is also shown that at a constant Re, carbon nanofluid is able to enhance the convective heat transfer coefficient up to 10.17%, compared with pure water. It is found that adding carbon nanoparticles to water, initially leads to increasing the convective heat transfer coefficient, while this trend continues until the concentration of about 0.2 wt%, and then has a descending trend. In addition, the pressure drop was investigated due to changes in Re and was shown that the behavior of this curve is in agreement with Moody’s diagram. The heat transfer coefficient of fluid is one of the most important effective factors on the performance of fluid in the heat transfer process. Due to the higher conductive heat transfer coefficient of metals than liquids, metal particles can be used to increase the heat transfer rate of liquids. Nanofluid is one of the novels and developing methods to improve the heat transfer rate in heat exchangers. In this paper, the main effective parameters (flow rate and concentration) on increasing the convective heat transfer coefficient of water carbon nanofluid compared with water as a base fluid, are investigated in the Reynolds range of 7,100 to 16,700. The results illustrate that increasing the Re leads to increase in the Nusselt number and convective heat transfer coefficient, and also to decrease the friction factor. It is also shown that at a constant Re, carbon nanofluid is able to enhance the convective heat transfer coefficient up to 10.17%, compared with pure water. It is found that adding carbon nanoparticles to water, initially leads to increasing the convective heat transfer coefficient, while this trend continues until the concentration of about 0.2 wt%, and then has a descending trend. In addition, the pressure drop was investigated due to changes in Re and was shown that the behavior of this curve is in agreement with Moody’s diagram.

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