Lattice Boltzmann Modeling of Ultrafast Laser Heating on Metal Film

2013 ◽  
Author(s):  
Dadong Wang ◽  
Yanbao Ma
Keyword(s):  
Transport Equation ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Laser Heating ◽  
Metal Film ◽  
Phonon Scattering ◽  
Boltzmann Transport Equation ◽  
Ultrafast Laser ◽  
Boltzmann Transport ◽  
Boltzmann Method

Lattice Boltzmann method based on Boltzmann transport equation is developed to simulate the nanoscale heat transport in metal film. The Boltzmann transport equation is applicable to describe both electron and phonon scattering processes: the absorption of photon energy by electrons and the subsequent heating of metal lattice (phonons) through electron-phonon collisions. We show that the Boltzmann transport equation can give rise to the well-known two-temperature model. To validate our numerical tool, ultrafast laser heating on metal film is analyzed by lattice Boltzmann method and finite difference method based on two-step model separately, and exactly the same results are obtained. The predicted transient reflectivity changes agree with picosecond laser heating experiments data also.

scholarly journals Modelling of transient heat transport in metal films using the interval lattice Boltzmann method

2016 ◽  
Vol 64 (3) ◽  
pp. 599-606 ◽  
Author(s):  
A. Piasecka Belkhayat ◽  
A. Korczak
Keyword(s):  
Lattice Boltzmann Method ◽  
Heat Transport ◽  
Lattice Boltzmann ◽  
Relaxation Times ◽  
Metal Films ◽  
Thin Metal ◽  
Heating Process ◽  
Boltzmann Transport ◽  
Thin Metal Films ◽  
Boltzmann Method

Abstract In the paper a description of heat transfer in one-dimensional crystalline solids is presented. The lattice Boltzmann method based on Boltzmann transport equation is used to simulate the nanoscale heat transport in thin metal films. The coupled lattice Boltzmann equations for electrons and phonons are applied to analyze the heating process of thin metal films via laser pulse. Such approach in which the parameters appearing in the problem analyzed are treated as constant values is widely used, but in the paper the interval values of relaxation times and electron-phonon coupling factor are taken into account. The problem formulated has been solved by means of the interval lattice Boltzmann method using the rules of directed interval arithmetic. In the final part of the paper the results of numerical computations are shown.

Prediction of Non-Equilibrium Heat Conduction Using Parallel Computation of the Phonon Boltzmann Transport Equation

2014 ◽  
Author(s):  
Syed A. Ali ◽  
Gautham Kollu ◽  
Sandip Mazumder ◽  
P. Sadayappan
Keyword(s):  
Heat Conduction ◽  
Transport Equation ◽  
Parallel Computation ◽  
Large Scale ◽  
Phonon Scattering ◽  
Boltzmann Transport Equation ◽  
Computational Time ◽  
Spectral Space ◽  
Boltzmann Transport ◽  
Non Equilibrium

Non-equilibrium heat conduction, as occurring in modern-day sub-micron semiconductor devices, can be predicted effectively using the Boltzmann Transport Equation (BTE) for phonons. In this article, strategies and algorithms for large-scale parallel computation of the phonon BTE are presented. An unstructured finite volume method for spatial discretization is coupled with the control angle discrete ordinates method for angular discretization. The single-time relaxation approximation is used to treat phonon-phonon scattering. Both dispersion and polarization of the phonons are accounted for. Three different parallelization strategies are explored: (a) band-based, (b) direction-based, and (c) hybrid band/cell-based. Subsequent to validation studies in which silicon thin-film thermal conductivity was successfully predicted, transient simulations of non-equilibrium thermal transport were conducted in a three-dimensional device-like silicon structure, discretized using 604,054 tetrahedral cells. The angular space was discretized using 400 angles, and the spectral space was discretized into 40 spectral intervals (bands). This resulted in ∼9.7×109 unknowns, which are approximately 3 orders of magnitude larger than previously reported computations in this area. Studies showed that direction-based and hybrid band/cell-based parallelization strategies resulted in similar total computational time. However, the parallel efficiency of the hybrid band/cell-based strategy — about 88% — was found to be superior to that of the direction-based strategy, and is recommended as the preferred strategy for even larger scale computations.

Estimation of an Appropriate Lattice Structure for Phonon Transport Using Lattice Boltzmann Method

2013 ◽  
Author(s):  
Ankur Chattopadhyay ◽  
Arvind Pattamatta
Keyword(s):  
Thermal Conductivity ◽  
Heat Conduction ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Energy Transport ◽  
Lattice Structure ◽  
Detailed Comparison ◽  
Phonon Transport ◽  
Boltzmann Transport ◽  
Boltzmann Method

Heat transport at nanoscales departs substantially from the well established classical laws governing the physical processes at continuum level. The Fourier Law of heat conduction cannot be applied at sub-continuum level due to its inability in modeling non-equilibrium energy transport. Therefore one must resort to a rigorous solution to the Boltzmann Transport Equation (BTE) in the realm of nanoscale transport regime. Some recent studies show that a relatively inexpensive and accurate way to predict the behavior of sub continuum energy transport in solids is via the discrete representation of the BTE referred to as the Lattice Boltzmann method (LBM). Although quite a few numerical simulations involving LBM have been exercised in the literature, there has been no clear demonstration of the accuracy of LBM over BTE; also there exists an ambiguity over employing the right lattice configurations describing phonon transport. In the present study, the Lattice Boltzmann Method has been implemented to study phonon transport in miniaturized devices. The initial part of the study focuses upon a detailed comparison of the LBM model with that of BTE for one dimensional heat transfer involving multiple length and time scales. The second objective of the present investigation is to evaluate different lattice structures such as D1Q2, D1Q3, D2Q5, D2Q8, D2Q9 etc. for 1-D and 2-D heat conduction. In order to reduce the modeling complexity, gray model assumption based on Debye approximation is adopted throughout the analysis. Results unveil that the accuracy of solution increases as the number of lattice directions taken into account are incremented from D2Q5 to D2Q9. A substantial increase in solution time with finer directional resolutions necessitates an optimum lattice. A novel lattice dimension ‘Mod D2Q5’ has been suggested and its performance is also compared with its compatriots. It is also demonstrated that the inclusion of the center point within a particular lattice structure can play a significant role in the prediction of thermal conductivity in the continuum level. However, as the size of the device comes down to allow high Knudsen numbers, in the limiting case of ballistic phonon transport, the choice of lattice seems to have negligible effect on thermal conductivity.

Using the Lattice Boltzmann Method to Simulate the Heat Conduction in a Thin Film Induced by Ultra-Fast Laser

2015 ◽  
Vol 723 ◽  
pp. 896-900
Author(s):  
Yu Dong Mao ◽  
Ming Tian Xu
Keyword(s):  
Thin Film ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Laser Heating ◽  
Silicon Film ◽  
Fourier Law ◽  
Higher Temperature ◽  
Boltzmann Method ◽  
Heating Technology ◽  
Thin Silicon Film

Ultra-fast laser heating technology has been widely used in the micro-/nanodevices. The Lattice Boltzmann method (LBM) is employed to simulate the heat conductions of laser heating appeared in a thin film. The results obtained by the LBM show that a wavelike behavior is appeared, but it can not be found in Fourier prediction. Comparing the results obtained by the Fourier law and LBM, we find that the LBM solution shows higher temperature than the Fourier prediction. Moreover, simultaneously heating both surfaces of a thin silicon film by ultra-fast lasers can induce two thermal waves traveling in the opposite directions, and when they meet together, the energy will enhance significantly.

Size and edge roughness dependence of thermal conductivity for vacancy-defective graphene ribbons

2015 ◽  
Vol 17 (14) ◽  
pp. 8822-8827 ◽  
Author(s):  
Guofeng Xie ◽  
Yulu Shen
Keyword(s):  
Thermal Conductivity ◽  
Transport Equation ◽  
Phonon Scattering ◽  
Boltzmann Transport Equation ◽  
Boundary Scattering ◽  
Boltzmann Transport ◽  
Single Vacancy ◽  
Edge Roughness ◽  
Defective Graphene

By incorporating the phonon–phonon scattering, phonon-boundary scattering and phonon-vacancy scattering into the linearized Boltzmann transport equation, we theoretically investigate the effects of size and edge roughness on thermal conductivity of single vacancy-defective graphene ribbons.

Remote processes

2020 ◽  
pp. 632-648
Author(s):  
Sandip Tiwari
Keyword(s):  
Electron Transport ◽  
Transport Equation ◽  
Short Range ◽  
Phonon Scattering ◽  
Boltzmann Transport Equation ◽  
Local Effect ◽  
Seebeck Effect ◽  
Boltzmann Transport ◽  
Coulomb Interactions ◽  
High Permittivity

This chapter discusses remote processes that influence electron transport and manifest themselves in a variety of properties of interest. Coulomb and phonon-based interactions have appeared in many discussions in the text. Coulomb interactions can be short range or long range, but phonons have been treated as a local effect. At the nanoscale, the remote aspects of these interactions can become significant. An off-equilibrium distribution of phonons, in the limit of low scattering, will lead to the breakdown of the local description of phonon-electron coupling. Phonons can drag electrons, and electrons can drag phonons. Soft phonons—high permittivity—can cause stronger electron-electron interactions. So, plasmon scattering can become significant. Remote phonon scattering too becomes important. These and other such changes are discussed, together with phonon drag’s consequences for the Seebeck effect, as illustrated through the coupled Boltzmann transport equation. The importance of the zT coefficient for characterizing thermoelectric capabilities is stressed.

Sub-Continuum Heat Conduction in Electronics Using the Lattice Boltzmann Method

2003 ◽  
Author(s):  
Sartaj S. Ghai ◽  
Rodrigo A. Escobar ◽  
Myung S. Jhon ◽  
Cristina H. Amon
Keyword(s):  
Heat Conduction ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Internal Heat ◽  
Numerical Data ◽  
Computational Effort ◽  
Silicon On Insulator ◽  
Boltzmann Transport ◽  
Boltzmann Method

The lattice Boltzmann method (LBM) is used to examine multi-length scale, confined heat conduction problems in one dimension for which sub-continuum effects are important. This paper describes the implementation of the method and its application to electronic devices. A silicon-on-insulator device with internal heat generation is used as a case study to illustrate the advantages of the LBM. We compare our results with various hierarchical equations of heat transfer such as Fourier, Cattaneo, and Boltzmann transport equations, as well as with experimental and numerical data from the literature. Our results provide excellent agreement with other methodologies, at a far less computational effort.

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