Forced convection in a double tube heat exchanger using nanofluids with constant and variable thermophysical properties
International Journal of Numerical Methods for Heat & Fluid Flow
ISSN: 0961-5539
Article publication date: 29 July 2019
Issue publication date: 22 May 2020
Abstract
Purpose
This paper aims to study forced convection in a double tube heat exchanger using nanofluids with constant and variable thermophysical properties.
Design/methodology/approach
The cold fluid was distilled water flowing in the annulus and the hot fluid was aluminum oxide/water nanofluid which flows in the inner tube. Thermal conductivity and viscosity were taken as variable thermophysical properties, and the results were compared against runs with constant values. Finite volume method was used for solving the governing equations. For distilled water, Re = 500 was used, while for nanofluid, nanoparticles volume fraction equal to 2.5-10 per cent and Re = 100-1,500 were used.
Findings
Heat transfer rate can be enhanced by increasing the volume fraction of nanoparticles and Reynolds number. Thermal efficiency is better with constant thermophysical characteristics and the average Nusselt number is better for variable characteristics.
Originality/value
Heat exchanger efficiency is evaluated by using distilled water and nanofluid bulk temperature, thermal efficiency and average and local Nusselt numbers for both variable and constant thermophysical characteristics.
Keywords
Acknowledgements
Conflicts of interest: The authors declare that there is no conflict of interest regarding the publication of this paper.
Citation
Bahmani, M.H., Akbari, O.A., Zarringhalam, M., Ahmadi Sheikh Shabani, G. and Goodarzi, M. (2020), "Forced convection in a double tube heat exchanger using nanofluids with constant and variable thermophysical properties", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 30 No. 6, pp. 3247-3265. https://doi.org/10.1108/HFF-01-2019-0017
Publisher
:Emerald Publishing Limited
Copyright © 2019, Emerald Publishing Limited