Natural convection of large Prandtl number fluids: a controversy answered by a new thermal lattice Boltzmann model

Sheng Chen*, Kai H. Luo, Amit Kumar Jain, Dharminder Singh, Don McGlinchey

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)
53 Downloads (Pure)

Abstract

The purpose of this work is to deepen our understanding of natural convection with large Prandtl number fluids and to resolve some controversies in the previous publications. To achieve this purpose, a new thermal multiple-relaxation-time lattice Boltzmann model is proposed. Natural convection in a square cavity, a benchmark test case, is investigated numerically using the new model. The Prandtl number is up to 100. For the first time, it is numerically observed that there are two critical Prandtl numbers in the natural convection, which will affect the correlation between the Nusselt number and Prandtl number critically. Three heat transfer characteristic ranges of natural convection are defined in this work, according to the two critical Prandtl numbers. In each range, the dominant heat transfer mechanism is different, which can solve a long-standing issue in the discipline of heat and mass transfer: completely opposing statements on the correlation between the Nusselt number and Prandtl number for natural convection, were published in the open literature. For the first time, this work reveals cause behind the controversial reports and provides the guidance for the future research.

Original languageEnglish
Article number102827
Number of pages13
JournalCase Studies in Thermal Engineering
Volume44
Early online date20 Feb 2023
DOIs
Publication statusPublished - Apr 2023

Keywords

  • Natural convection
  • Lattice Boltzmann
  • Prandtl number
  • Nusselt number
  • Multiple-relaxation-time (MRT) model

ASJC Scopus subject areas

  • Engineering (miscellaneous)
  • Fluid Flow and Transfer Processes

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