Next Article in Journal
The Impact of Process Heat on the Decarbonisation Potential of Offshore Installations by Hybrid Energy Systems
Previous Article in Journal
Numerical Investigation of the Secondary Swirling in Supersonic Flows of Various Nature Gases
Review

Legitimacy of the Local Thermal Equilibrium Hypothesis in Porous Media: A Comprehensive Review

1
Energy and Renewable Energies Technology Centre, University of Technology, Baghdad 19006, Iraq
2
Department of Mechanical and Aerospace Engineering, Monash University, Clayton, VIC 3800, Australia
3
Department of Electrochemical Engineering, University of Technology, Baghdad 19006, Iraq
4
Mechanical Engineering Department, University of Technology, Baghdad 19006, Iraq
5
School of Engineering and Technology, Central Queensland University, Brisbane, QLD 4009, Australia
*
Author to whom correspondence should be addressed.
Academic Editors: Gianpiero Colangelo and Chi-Ming Lai
Energies 2021, 14(23), 8114; https://doi.org/10.3390/en14238114
Received: 26 October 2021 / Revised: 22 November 2021 / Accepted: 26 November 2021 / Published: 3 December 2021
Local thermal equilibrium (LTE) is a frequently-employed hypothesis when analysing convection heat transfer in porous media. However, investigation of the non-equilibrium phenomenon exhibits that such hypothesis is typically not true for many circumstances such as rapid cooling or heating, and in industrial applications involving immediate transient thermal response, leading to a lack of local thermal equilibrium (LTE). Therefore, for the sake of appropriately conduct the technological process, it has become necessary to examine the validity of the LTE assumption before deciding which energy model should be used. Indeed, the legitimacy of the LTE hypothesis has been widely investigated in different applications and different modes of heat transfer, and many criteria have been developed. This paper summarises the studies that investigated this hypothesis in forced, free, and mixed convection, and presents the appropriate circumstances that can make the LTE hypothesis to be valid. For example, in forced convection, the literature shows that this hypothesis is valid for lower Darcy number, lower Reynolds number, lower Prandtl number, and/or lower solid phase thermal conductivity; however, it becomes invalid for higher effective fluid thermal conductivity and/or lower interstitial heat transfer coefficient. View Full-Text
Keywords: convection heat transfer; porous media; LTE; LTNE convection heat transfer; porous media; LTE; LTNE
Show Figures

Figure 1

MDPI and ACS Style

Al-Sumaily, G.F.; Al Ezzi, A.; Dhahad, H.A.; Thompson, M.C.; Yusaf, T. Legitimacy of the Local Thermal Equilibrium Hypothesis in Porous Media: A Comprehensive Review. Energies 2021, 14, 8114. https://doi.org/10.3390/en14238114

AMA Style

Al-Sumaily GF, Al Ezzi A, Dhahad HA, Thompson MC, Yusaf T. Legitimacy of the Local Thermal Equilibrium Hypothesis in Porous Media: A Comprehensive Review. Energies. 2021; 14(23):8114. https://doi.org/10.3390/en14238114

Chicago/Turabian Style

Al-Sumaily, Gazy F., Amged Al Ezzi, Hayder A. Dhahad, Mark C. Thompson, and Talal Yusaf. 2021. "Legitimacy of the Local Thermal Equilibrium Hypothesis in Porous Media: A Comprehensive Review" Energies 14, no. 23: 8114. https://doi.org/10.3390/en14238114

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop