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Investigation of the effects of geometrical parameters, eccentricity and perforated fins on natural convection heat transfer in a finned horizontal annulus using three dimensional lattice Boltzmann flux solver

Ashouri, M ; Sharif University of Technology | 2022

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  1. Type of Document: Article
  2. DOI: 10.1108/HFF-10-2020-0629
  3. Publisher: Emerald Publishing , 2022
  4. Abstract:
  5. Purpose: The purpose of this paper is to investigate the effects of geometrical parameters, eccentricity and perforated fins on natural convection heat transfer in a finned horizontal annulus using three-dimensional lattice Boltzmann flux solver. Design/methodology/approach: Three-dimensional lattice Boltzmann flux solver is used in the present study for simulating conjugate heat transfer within an annulus. D3Q15 and D3Q7 models are used to solve the fluid flow and temperature field, respectively. The finite volume method is used to discretize mass, momentum and energy equations. The Chapman–Enskog expansion analysis is used to establish the connection between the lattice Boltzmann equation local solution and macroscopic fluxes. To improve the accuracy of the lattice Boltzmann method for curved boundaries, lattice Boltzmann equation local solution at each cell interface is considered to be independent of each other. Findings: It is found that the maximum heat transfer rate occurs at low fin spacing especially by increasing the fin height and decreasing the internal-cylindrical distance. The effect of inner cylinder eccentricity is not much considerable (up to 5.2% enhancement) while the impact of fin eccentricity is more remarkable. Negative fin eccentricity further enhances the heat transfer rate compared to a positive fin eccentricity and the maximum heat transfer enhancement of 91.7% is obtained. The influence of using perforated fins is more considerable at low fin spacing although some heat transfer enhancements are observed at higher fin spacing. Originality/value: The originality of this paper is to study three-dimensional natural convection in a finned-horizontal annulus using three-dimensional lattice Boltzmann flux solver, as well as to apply symmetry and periodic boundary conditions and to analyze the effect of eccentric annular fins (for the first time for air) and perforated annular fins (for the first time so far) on the heat transfer rate. © 2021, Emerald Publishing Limited
  6. Keywords:
  7. Annular fins ; Perforated fins ; Three-dimensional lattice Boltzmann flux solver ; Boltzmann equation ; Finite volume method ; Fins (heat exchange) ; Flow of fluids ; Geometry ; Horizontal wells ; Annular fin ; Eccentricity ; Fin spacing ; Heat transfer rate ; Horizontal annulus ; Lattice boltzmann ; Parametric study ; Perforated fin ; Three-dimensional lattice boltzmann flux solv ; Three-dimensional lattices ; Natural convection
  8. Source: International Journal of Numerical Methods for Heat and Fluid Flow ; Volume 32, Issue 1 , 2022 , Pages 283-312 ; 09615539 (ISSN)
  9. URL: https://www.emerald.com/insight/content/doi/10.1108/HFF-10-2020-0629/full/html