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An Analysis of Heat Conduction Models for Nanofluids

2010; Taylor & Francis; Volume: 31; Issue: 14 Linguagem: Inglês

10.1080/01457631003689211

1521-0537

João Nazareno Nonato Quaresma, Emanuel Negrão Macêdo, Henrique Massard da Fonseca, Helcio R. B. Orlande, Renato M. Cotta,

Heat Transfer Mechanisms

Abstract The mechanism of heat transfer intensification recently brought about by nanofluids is analyzed in this article, in the light of the non-Fourier dual-phase-lagging heat conduction model. The physical problem involves an annular geometry filled with a nanofluid, such as typically used for measurements of the thermal conductivity with Blackwell's line heat source probe. The mathematical formulation for this problem is analytically solved with the classical integral transform technique, thus providing benchmark results for the temperature predicted with the dual-phase-lagging model. Different test cases are examined in this work, involving nanofluids and probe sizes of practical interest. The effects of the relaxation times on the temperature at the surface of the probe are also examined. The results obtained with the dual-phase-lagging model are critically compared to those obtained with the classical parabolic model, showing that the increase in the thermal conductivity of nanofluids measured with the line heat source probe cannot be attributed to hyperbolic effects. Acknowledgments The authors acknowledge the financial support provided by CNPq for the postdoctoral fellowship of Professor J. N. N. Quaresma at the Laboratory of Heat Transmission and Technology of the Mechanical Engineering Department of COPPE/UFRJ. This work was partially sponsored by CAPES and FAPERJ, with major financial support provided by Petrobras S.A.