Next Article in Journal
Synchronization of Fractional-Order Complex Chaotic Systems Based on Observers
Next Article in Special Issue
Entropy Generation of Forced Convection during Melting of Ice Slurry
Previous Article in Journal
3D CNN-Based Speech Emotion Recognition Using K-Means Clustering and Spectrograms
Previous Article in Special Issue
Energy and Entropy in Turbulence Decompositions
Article Menu
Issue 5 (May) cover image

Export Article

Open AccessArticle

Heat Transfer and Entropy Generation Abilities of MWCNTs/GNPs Hybrid Nanofluids in Microtubes

Department of Mechanical Engineering, Faculty of Engineering, Al-Hussein Bin Talal University, P.O. Box 20, Ma’an, Jordan
School of Mechanical Engineering, Engineering Campus, Universiti Sains Malaysia, Nibong Tebal 14300, Penang, Malaysia
Faculty of Chemical Engineering, Jalan Ilmu 1/1, Universiti Teknologi MARA, Shah Alam 40450, Selangor, Malaysia
Mechatronics Engineering Department, German Jordanian University, Amman 11180, Jordan
Department of Chemical and Process Engineering, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor Darul Ehsan, Malaysia
Process and Energy Department, Delft University of Technology, Leeghwaterstraat 39, 2628 CB Delft, The Netherlands
Authors to whom correspondence should be addressed.
Entropy 2019, 21(5), 480;
Received: 17 March 2019 / Revised: 4 April 2019 / Accepted: 13 April 2019 / Published: 9 May 2019
(This article belongs to the Special Issue Entropy Production in Turbulent Flow)
PDF [4713 KB, uploaded 9 May 2019]


Massive improvements in the thermophysical properties of nanofluids over conventional fluids have led to the rapid evolution of using multiwalled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) in the field of heat transfer. In this study, the heat transfer and entropy generation abilities of MWCNTs/GNPs hybrid nanofluids were explored. Experiments on forced convective flow through a brass microtube with 300 µm inner diameter and 0.27 m in length were performed under uniform heat flux. MWCNTs/GNPs hybrid nanofluids were developed by adding 0.035 wt.% GNPs to MWCNTs water-based nanofluids with mass fractions of 0.075–0.125 wt.%. The range of the Reynolds number in this experiment was maintained at Re = 200–500. Results showed that the conventional approach for predicting the heat transfer coefficient was applicable for microtubes. The heat transfer coefficient increased markedly with the use of MWCNTs and MWCNTs/GNPs nanofluids, with increased pressure dropping by 12.4%. Results further showed a reduction by 37.5% in the total entropy generation rate in microtubes for hybrid nanofluids. Overall, MWCNTs/GNPs hybrid nanofluids can be used as alternative fluids in cooling systems for thermal applications. View Full-Text
Keywords: MWCNTs; GNPs; hybrid nanofluid; microtube; heat transfer coefficient MWCNTs; GNPs; hybrid nanofluid; microtube; heat transfer coefficient

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Hussien, A.A.; Abdullah, M.Z.; Yusop, N.M.; Al-Kouz, W.; Mahmoudi, E.; Mehrali, M. Heat Transfer and Entropy Generation Abilities of MWCNTs/GNPs Hybrid Nanofluids in Microtubes. Entropy 2019, 21, 480.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Entropy EISSN 1099-4300 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top