Investigation of couple effects on hyperbolic heat and mass transfer

• Main Authors: Hui-Chuan Lin, 林慧娟
• Other Authors: Ming-I Char
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/28883212425615631396

博士 === 國立中興大學 === 應用數學系所 === 98 === In this paper, the couple effects of hyperbolic heat and mass transfer in a thin film irradiated by ultrashort-pulsed lasers were investigated. Non-Fourier or non-Fickian model, considered as a hyperbolic model includes relaxation-time term in the equation. The temperature and concentration curves may appear discontinuities. The sharp discontinuity curve is a characteristic of the hyperbolic equation and is generated by wave propagation. The vicinity of sharp discontinuities always result numerical oscillations. The Laplace transform method is used, in this study, to obtain a local-analytic solution in the transformed domain and then inverted to obtain the results in physical quantities. The local-analytical-method for solving sharp discontinuity curves to avoid numerical oscillation and obtain accurate results is presented in this paper. When the heating time is ultra-short and close to the time needed for electrons and lattice to reach thermal equilibrium, the two-step model is needed to be taken into account. One of the studyes in this paper is an investigation of the couple effects on two-step hyperbolic heat and mass transfer that irradiated by ultrashort-pulsed lasers. Therefore, two-step couple equations of electron and lattice will be studied in this study. When considering the Soret effects for mass transfer, the intensity of the concentration decline or rise is larger as the Soret coefficient is larger. Similarly, when considering the Dufour effects for heat transfer, the intensity of the heat wave rise is larger as the Dufour coefficient is larger. When considering the couple effects of Soret and Dufour, the mass and heat wave fronts occur at the same locations and shift to left comparing with no couple effect. The shift distance is larger in the right side as the waves propagated to right. Summary of this paper, couple effects on hyperbolic heat and mass transfer in a slab that irradiated by ultrashort-pulsed lasers have studied. The subjects studied include wave propagation, wave reflection, Soret effect, Dufour effect, couple effect and the electron and lattice temperature distributions in the ultra-short time.