scholarly journals Simulating transient heat transfer in graphene at finite Knudsen number via the Boltzmann transport equation and molecular dynamics

2020 ◽  
Vol 102 (20) ◽  
Author(s):  
Joel G. Christenson ◽  
Matthew P. Kroonblawd ◽  
Ryan A. Austin ◽  
Laurence E. Fried ◽  
Ronald J. Phillips
Keyword(s):  
Heat Transfer ◽  
Molecular Dynamics ◽  
Transport Equation ◽  
Knudsen Number ◽  
Boltzmann Transport Equation ◽  
Transient Heat Transfer ◽  
Boltzmann Transport

Study of an Iterative Solution for Boltzmann Transport Equation and Calculation of Thermal Conductivity

2018 ◽  
Vol 777 ◽  
pp. 421-425 ◽  
Author(s):  
Chhengrot Sion ◽  
Chung Hao Hsu
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Numerical Calculation ◽  
Iterative Method ◽  
Transport Equation ◽  
Linear Systems ◽  
Heat Transport ◽  
Boltzmann Transport Equation ◽  
Iterative Solution ◽  
Boltzmann Transport

Many methods have been developed to predict the thermal conductivity of the material. Heat transport is complex and it contains many unknown variables, which makes the thermal conductivity hard to define. The iterative solution of Boltzmann transport equation (BTE) can make the numerical calculation and the nanoscale study of heat transfer possible. Here, we review how to apply the iterative method to solve BTE and many linear systems. This method can compute a sequence of progressively accurate iteration to approximate the solution of BTE.

DSMC for Phonon Transport in Solid Thin Films

2009 ◽  
Author(s):  
Mitsuhiro Matsumoto ◽  
Masaya Okano
Keyword(s):  
Heat Transfer ◽  
Thin Films ◽  
Relaxation Time ◽  
Transport Equation ◽  
Boltzmann Transport Equation ◽  
Thermal Design ◽  
Dynamics Simulation ◽  
Boltzmann Transport ◽  
Phonon Dynamics ◽  
Solid Thin Films

As the scale of electronic devices decreases, heat transfer analysis and thermal design becomes more important. In particular, heat transfer through various solid thin films is strongly affected by thickness dependence of thermal conductivity and interfacial thermal resistance. Analysis of phonon dynamics based on a linearized Boltzmann transport equation, or the so-called relaxation time approximation, has been widely used, but detailed analysis using molecular dynamics simulation reveals that couplings among various phonon modes can affect the energy transfer. In this study, we propose a DSMC scheme to simulate phonon dynamics starting from the original Boltzmann transport equation. In contrast to the linearized model, this scheme requires no relaxation time as an input parameter, and we can investigate the couplings among phonons with different modes, although we have to assume some appropriate model of phonon-phonon collisions. As a test calculation, energy flux was evaluated for model thin films of various thicknesses, and a phenomenon similar to the Casimir limit was retrieved. This scheme will enable us to include other factors, such as phonon-electron couplings.

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