Wall-to-bed heat transfer in supercritical water fluidized bed using CFD-DEM--颗粒学报PARTICUOLOGY

Zhang, T., & Lu, Y. (2021). Wall-to-bed heat transfer in supercritical water fluidized bed using CFD-DEM. Particuology, 56, 113-123. https://doi.org/10.1016/j.partic.2020.10.011

Wall-to-bed heat transfer in supercritical water fluidized bed using CFD-DEM

Tianning Zhang, Youjun Lu ^*

State Key Laboratory of Multiphase Flow in Power Engineering (SKLMFPE), Xi’an Jiaotong University, Xi’an, Shaanxi 710049, PR China

10.1016/j.partic.2020.10.011

Volume 56, June 2021, Pages 113-123

Received 28 June 2020, Revised 25 September 2020, Accepted 12 October 2020, Available online 30 November 2020, Version of Record 8 March 2021.

E-mail: yjlu@mail.xjtu.edu.cn

Highlights

• Two methods to deal with multiphase heat flux boundary are compared in SCWFB.

• Zhang’s method predicts more accurate wall-to-bed heat transfer coefficients.

• Variables that are difficult to experimentally study are simulated.

• Effects of solid physical properties on wall-to-bed heat transfer are considered.

Abstract

Supercritical water fluidized bed (SCWFB) reactors are designed to gasify biomass or coal with high efficiency. In this paper, the wall-to-bed heat transfer characteristics in SCWFB are studied using the computational fluid dynamics and discrete element method (CFD-DEM) coupled with a constant heat flux boundary. Two different methods are considered to deal with the multiphase heat flux boundary in CFD-DEM because there is currently no single widely accepted approach. Zhang’s method predicts a more accurate wall-to-bed heat transfer coefficient in SCWFB than Lattanzi’s method according to comparisons of the simulation results with an empirical correlation. The influences of temperature, pressure, velocity, and the solid phase properties, such as the particle diameter, particle heat capacity, particle thermal conductivity, and particle density, on the SCWFB wall-to-bed heat transfer characteristics are studied based on Zhang’s method. The simulation results help reveal the SCWFB heat transfer characteristics.

Graphical abstract

Keywords

Supercritical water; Fluidized bed; Heat transfer; DEM-CFD; Constant heat flux

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