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Bin S Mansour - One of the best experts on this subject based on the ideXlab platform.
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analytical solution of hyperbolic heat conduction equation in relation to laser short pulse heating
Physica B-condensed Matter, 2011Co-Authors: B S Yilbas, Ahmad Y Aldweik, Bin S MansourAbstract:In the present study, the hyperbolic heat conduction equation is derived from the Boltzmann transport equation and the analytical solution of the resulting equation appropriate to the laser short-pulse heating of a solid surface is presented. The time exponentially decaying pulse is incorporated as a volumetric heat source in the hyperbolic equation to account for the absorption of the incident laser Energy. The Fourier transformation is used to simplify the hyperbolic equation and the analytical solution of the simplified equation is obtained using the Laplace transformation method. Temperature distribution in space and time are computed in steel for two laser pulse parameters. It is found that Internal Energy Gain from the irradiated field, due to the presence of the volumetric heat source in the hyperbolic equation, results in rapid rise of temperature in the surface region during the early heating period. In addition, temperature decay is gradual in the surface region and as the depth below the surface increases beyond the absorption depth, temperature decay becomes sharp.
Bekir Sami Yilbas - One of the best experts on this subject based on the ideXlab platform.
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Three-Dimensional Laser Heating Model and Entropy Generation Consideration
Journal of Energy Resources Technology, 1999Co-Authors: Bekir Sami YilbasAbstract:Lasers find wide applications in heat treatment of engineering parts. The modeling and Energy analysis of the heating process can reduce substantially the time required for process optimization and control. In the present study, three-dimensional laser heating model is introduced using an electron kinetic theory approach, the Energy analysis is carried out to predict the first and second law efficiencies, and the entropy generation number is computed during the process. The equation derived for the heat conduction is in the form of an integro-differential equation, which does not yield an analytical solution. Therefore, a numerical method employing an explicit scheme is introduced to discretize the governing heat transfer equation. It is found that the electron lattice site atom collision is the determining process for the Internal Energy Gain of the substrate in the surface vicinity. In addition, the overall entropy generation number computed in the heating cycle is less than what occurs in the cooling cycle of the heat treatment process.
B S Yilbas - One of the best experts on this subject based on the ideXlab platform.
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analytical solution of hyperbolic heat conduction equation in relation to laser short pulse heating
Physica B-condensed Matter, 2011Co-Authors: B S Yilbas, Ahmad Y Aldweik, Bin S MansourAbstract:In the present study, the hyperbolic heat conduction equation is derived from the Boltzmann transport equation and the analytical solution of the resulting equation appropriate to the laser short-pulse heating of a solid surface is presented. The time exponentially decaying pulse is incorporated as a volumetric heat source in the hyperbolic equation to account for the absorption of the incident laser Energy. The Fourier transformation is used to simplify the hyperbolic equation and the analytical solution of the simplified equation is obtained using the Laplace transformation method. Temperature distribution in space and time are computed in steel for two laser pulse parameters. It is found that Internal Energy Gain from the irradiated field, due to the presence of the volumetric heat source in the hyperbolic equation, results in rapid rise of temperature in the surface region during the early heating period. In addition, temperature decay is gradual in the surface region and as the depth below the surface increases beyond the absorption depth, temperature decay becomes sharp.
Ahmad Y Aldweik - One of the best experts on this subject based on the ideXlab platform.
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analytical solution of hyperbolic heat conduction equation in relation to laser short pulse heating
Physica B-condensed Matter, 2011Co-Authors: B S Yilbas, Ahmad Y Aldweik, Bin S MansourAbstract:In the present study, the hyperbolic heat conduction equation is derived from the Boltzmann transport equation and the analytical solution of the resulting equation appropriate to the laser short-pulse heating of a solid surface is presented. The time exponentially decaying pulse is incorporated as a volumetric heat source in the hyperbolic equation to account for the absorption of the incident laser Energy. The Fourier transformation is used to simplify the hyperbolic equation and the analytical solution of the simplified equation is obtained using the Laplace transformation method. Temperature distribution in space and time are computed in steel for two laser pulse parameters. It is found that Internal Energy Gain from the irradiated field, due to the presence of the volumetric heat source in the hyperbolic equation, results in rapid rise of temperature in the surface region during the early heating period. In addition, temperature decay is gradual in the surface region and as the depth below the surface increases beyond the absorption depth, temperature decay becomes sharp.
Fan Guo - One of the best experts on this subject based on the ideXlab platform.
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particle acceleration in kinetic simulations of non relativistic magnetic reconnection with different ion electron mass ratio
arXiv: Plasma Physics, 2019Co-Authors: Fan GuoAbstract:By means of fully kinetic particle-in-cell simulations, we study whether the proton-to-electron mass ratio $m_i/m_e$ influences the Energy spectrum and underlying acceleration mechanism during magnetic reconnection. While kinetic simulations are essential for studying particle acceleration during magnetic reconnection, a reduced $m_i/m_e$ is often used to alleviate the demanding computing resources, which leads to artificial scale separation between electron and proton scales. Recent kinetic simulations with high-mass-ratio have suggested new regimes of reconnection, as electron pressure anisotropy develops in the exhaust region and supports extended current layers. In this work, we study whether different $m_i/m_e$ changes the particle acceleration processes by performing a series of simulations with different mass ratio ($m_i/m_e=25-400$) and guide-field strength in a low-$\beta$ plasma. We find that mass ratio does not strongly influence reconnection rate, magnetic Energy conversion, ion Internal Energy Gain, plasma energization processes, ion Energy spectra, and the acceleration mechanisms for high-Energy ions. Simulations with different mass ratios are different in electron acceleration processes, including electron Internal Energy Gain, electron Energy spectrum and the acceleration efficiencies for high-Energy electrons. We find that high-Energy electron acceleration becomes less efficient when the mass ratio gets larger because the \textit{Fermi}-like mechanism associated with particle curvature drift becomes less efficient. These results indicate that when particle curvature drift dominates high-Energy particle acceleration, the further the particle kinetic scales are from the magnetic field curvature scales ($\sim d_i$), the weaker the acceleration will be.