Lattice Boltzmann simulation of TiO2-water nanofluid in a curved boundary domain at high Rayleigh numbers

Hosseini Abadshapoori, M | 2018

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  1. Type of Document: Article
  2. DOI: 10.1016/j.compfluid.2018.04.004
  3. Publisher: Elsevier Ltd , 2018
  4. Abstract:
  5. In this paper, a two-component Lattice Boltzmann Method (LBM) has been utilized to simulate the natural convection of TiO2-water nanofluid in a curved geometry. The main purpose of this research is to study the effect of nanoparticle size and also boundary conditions on the thermal characteristics of the nanofluid. Furthermore, the effect of Rayleigh number (Ra) and volume fraction of nanoparticles (ϕ) on the average Nusselt number (Nuave) have been investigated. Two different thermal boundary conditions, namely adiabatic and constant temperature, have been considered in the current work for the curved boundaries. The Rayleigh number varies from 103 to 109. Four different sizes, namely 10, 25, 65 and 90 nm, have been chosen for nanoparticles. Results show that the augmentation of nanoparticle size has a deteriorating effect on the effectiveness of nanoparticles while increasing Ra number and ϕ improves Nusselt number (Nu). It is also shown that the boundary conditions change the enhanced Nusselt number (Nu*). The effect is shown to be due to the variation of nanoparticles motion dictated by the boundary conditions. Furthermore, results reveal that increasing volume fraction increases viscosity which at higher values of ϕ might reduce Nu*. © 2018 Elsevier Ltd
  6. Keywords:
  7. High Rayleigh number ; Nanofluid ; Two component ; Boundary conditions ; Computational fluid dynamics ; Kinetic theory ; Nanoparticles ; Natural convection ; Nusselt number ; Titanium dioxide ; Volume fraction ; Curved boundary ; Lattice Boltzmann method ; Nanofluids ; Rayleigh number ; Two-component ; Nanofluidics
  8. Source: Computers and Fluids ; Volume 168 , 30 May , 2018 , Pages 159-169 ; 00457930 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0045793018301920#!