Multiple-relaxation-time lattice Boltzmann model for simulation of free convection in axisymmetric nanofluid-filled annulus-experimental and numerical observations
International Journal of Numerical Methods for Heat & Fluid Flow
ISSN: 0961-5539
Article publication date: 3 September 2019
Issue publication date: 3 February 2020
Abstract
Purpose
The MRT lattice Boltzmann simulation of natural convection in a confined environment is carried out. The flow and heat transfer during natural convection in a symmetrical annulus are studied.
Design/methodology/approach
The cavity is filled with TiO2-water nanofluid, and the thermal conductivity and dynamic viscosity of nanofluid are measured experimentally. The experimental data are utilized in the numerical simulations. The nanofluids are prepared at four different nanoparticle concentrations φ = 0, 0.1, 0.3 and 0.5. It is notable that the radial coordinate is used into the temperature distribution function. As a result, only one source term is required for the present lattice Boltzmann model. On the other hand, the macro cylindrical energy equation is exactly recovered using Chapman–Enskog analysis.
Findings
Influence of some main parameters including Rayleigh number in range of 103 to 106, solid volume fraction of nanofluid in range of 0 to 0.5 and four different aspect ratios on the the nanofluid flow (i.e. streamlines), heat transfer (i.e. temperature distribution and average Nusselt number) and entropy generation (i.e. total entropy generation and Bejan number) are presented, quantitatively and graphically. It is found that adding TiO2 nanoparticles to the base fluid has considerable positive effect on the heat transfer performance and entropy generation. In addition, the configuration of the annulus can be good controlling parameter on the heat transfer rate during natural convection.
Originality/value
The originality of this work is using of a modern numerical method to simulate the free convection and conducting experimental observations to calculate the thermo-physical properties of nanofluid. In addition, the numerical and experimental works are combined to provide accurate results.
Keywords
Acknowledgements
Retraction notice: The publishers of International Journal of Numerical Methods for Heat & Fluid Flow wish to retract the article “Multiple-relaxation-time lattice Boltzmann model for simulation of free convection in axisymmetric nanofluid-filled annulus-experimental and numerical observations” by H Sun and D Ross which appeared in Volume 30, Issue 2, 2020.
It has come to our attention that there are concerns regarding the identity of the author “David Ross” and the originality of this paper. A reasonable description of authors’ contribution to the paper has not been provided and concerns regarding its originality have not been addressed.
Despite numerous attempts to contact the authors, the journal has received no response; the response of the authors would be gratefully received.
The International Journal of Numerical Methods for Heat & Fluid Flow submission guidelines make it clear that only those who have made a substantial contribution to the article should be credited as authors and that articles must be original. The publishers of the journal sincerely apologize to the readers.
Citation
Sun, H. and Ross, D. (2020), "Multiple-relaxation-time lattice Boltzmann model for simulation of free convection in axisymmetric nanofluid-filled annulus-experimental and numerical observations", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 30 No. 2, pp. 934-955. https://doi.org/10.1108/HFF-05-2019-0400
Publisher
:Emerald Publishing Limited
Copyright © 2019, Emerald Publishing Limited