Thermomass Theory: A Mechanical Pathway to Analyze Anomalous Heat Conduction in Nanomaterials

Dong, Yuan; Cao, Bing-Yang; Guo, Zeng-Yuan

doi:10.5772/67780

Cited by 3 publications

(2 citation statements)

References 57 publications

(69 reference statements)

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“…Available at www.ThermalFluidsCentral.org established (Wang, 2014;Cao and Guo, 2007;Guo and Hou, 2010;Dong et al, 2017;Dong et al, 2012;Gupta and Mukhopadhyay, 2019;Freitas et al, 2016;Wang et al, 2014;Jou et al, 2011;Cimmelli et al, 2016;Dong, 2016). For the second challenge, the fundamental reason why the principle of minimum entropy generation is not applicable to the optimization of heat transfer without energy conversion is that entropy is the core physical quantity in thermodynamics, whose research object is the conversion law between heat and other forms of energy, rather than in heat transfer, whose research object is the transfer law of heat.…”

Section: Frontiers In Heat and Mass Transfermentioning

confidence: 99%

Physical Heat Transfer

Wang¹,

Guo²

2019

Frontiers in Heat and Mass Transfer

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The classical heat transfer theory is established on the empirical models of Fourier's heat conduction law and Newton's cooling law. Although the classical theory has been successfully used in a wide range of industrial engineering applications, it lacks deep understanding of the physical mechanisms for energy transport and analytical methodology based on solid mathematical and mechanical principles. The rapid development of modern science and technology challenges the traditional heat transfer theory in two aspects: (1) Fourier's law of heat conduction is no longer valid under the ultra-fast laser heating or nanoscale conditions; (2) The optimization principle minimizing entropy generation is not suitable for heat transfer problems without heat to work conversion. In order to solve the first challenge, we reexamined the nature of heat and introduced new physical quantities, such as thermomass, thermomass velocity, thermomass energy. Then the heat transfer problems can be analyzed in the framework of vectorial fluid mechanics, and the thermomass momentum conservation equation has been established and known as a general law of heat transfer. For the second challenge, we introduced new physical quantities, entransy and entransy dissipation, by analogy between the heat conduction process and the electric conduction process. Unlike entropy as the core physical quantity in thermodynamics dealing with energy conversion, entransy is the quantity to represent the ability of heat transfer in an incompressible system. The entransy dissipation represents the irreversibility of heat transfer process. On this basis, the least action principle to minimize entransy dissipation can be used to optimize the heat transfer process and enhance energy efficiency. Because the physical essence of entransy is the thermomass potential energy, the entransy-based variational method is actually the energy method in heat transfer. All the new physical quantities, principles and methods form a new and independent knowledge system in heat transfer, which may be named "Physical heat transfer".

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Section: Frontiers In Heat and Mass Transfermentioning

confidence: 99%

Physical Heat Transfer

Wang¹,

Guo²

2019

Frontiers in Heat and Mass Transfer

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“…The smaller channel device was assumed to (13) nm for the current (2018) and less than (6) nm for long-term (2026) [4]. The Fourier's law has generally used to predict the diffusive heat conduction [5]. In nanoscale the characteristic time and size of nanodevice was smaller than the mean free path (MFP).…”

Section: Introductionmentioning

confidence: 99%

Study of Heat Dissipation Mechanism in Nanoscale MOSFETs Using BDE Model

Rezgui¹,

Nasri²,

Aissa³

et al. 2018

Green Electronics

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In this chapter, we report the nano-heat transport in metal-oxide-semiconductor field effect transistor (MOSFET). We propose a ballistic-diffusive model (BDE) to inquire the thermal stability of nanoscale MOSFET's. To study the mechanism of scattering in the interface oxide-semiconductor, we have included the specularity parameter defined as the probability of reflection at boundary. In addition, we have studied the effective thermal conductivity (ETC) in nanofilms we found that ETC depend with the size of nanomaterial. The finite element method (FEM) is used to resolve the results for a 10 nm channel length. The results prove that our proposed model is close to those results obtained by the Boltzmann transport equation (BTE).

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Revisit nonequilibrium thermodynamics based on thermomass theory and its applications in nanosystems

Hua,

Dong

2024

Journal of Non-Equilibrium Thermodynamics

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The development of non-Fourier heat conduction models is encouraged by the invalidity of Fourier’s law to explain heat conduction in ultrafast or ultrasmall systems. The production of negative entropy will result from the combination of traditional nonequlibrium thermodynamics and non-Fourier heat conduction models. To resolve this paradox, extended irreversible thermodynamics (EIT) introduces a new state variable. However, real dynamics variables like force and momentum are still missing from nonequilibrium thermodynamics and EIT’s generalized force and generalized flux. Heat has both mass and energy, according to thermomass theory and Einstein’s mass-energy relation. The generalized heat conduction model containing non-Fourier effects was established by thermomass gas model. The thermomass theory reshapes the concept of the generalized force and flux, temperature, and entropy production in nonequilibrium thermodynamics and revisits the assumption for the linear regression of the fluctuations in Onsager reciprocal relation. The generalized heat conduction model based on thermomass theory has been used to study thermal conductivity, thermoelectric effect, and thermal rectification effect in nanosystems.

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Thermomass Theory: A Mechanical Pathway to Analyze Anomalous Heat Conduction in Nanomaterials

Cited by 3 publications

References 57 publications

Physical Heat Transfer

Physical Heat Transfer

Study of Heat Dissipation Mechanism in Nanoscale MOSFETs Using BDE Model

Revisit nonequilibrium thermodynamics based on thermomass theory and its applications in nanosystems

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