Wyniki wyszukiwania - BazTech

1

Heat flux formulation for 1D dual-phase lag equation

Majchrzak E., Kałuża G.

Journal of Applied Mathematics and Computational Mechanics

|

2015

|

Vol. 14, nr 1

71--78

EN

The thin metal film subjected to the ultra-short laser pulse is analyzed. Heat transfer processes occurring in the domain considered are described by the dual-phase lag model in which the unknown is the heat flux, not, as usual, temperature. This approach is especially convenient in the case of Neumann boundary conditions, which are taken into account here. The mathematical model supplemented by initial conditions is solved using the explicit scheme of finite difference method. In the final part of the paper the examples of computations are shown and the conclusions are formulated.

2

Analiza wrażliwości cienkiej warstwy metalowej poddanej działaniu lasera

Majchrzak E., Dziatkiewicz J., Kałuża G.

Modelowanie Inżynierskie

|

2012

|

T. 12, nr 43

155-160

PL

Rozpatrywano cienką warstwę metalową poddaną działaniu lasera o ultrakrótkim impulsie. Przewodzenie ciepła w warstwie opisano za pomocą modelu dwutemperaturowego składającego się z układu dwóch sprzężonych równań parabolicznych określających temperaturę gazu elektronowego i sieci krystalicznej. Przeprowadzono analizę wrażliwości pól temperatury ze względu na grubość warstwy. W tym celu wykorzystano podejście bezpośrednie analizy wrażliwości kształtu z zastosowaniem pochodnej materialnej. Pokazano wyniki obliczeń oraz sformułowano wnioski.

EN

The thin metal film subjected to the ultrashort laser pulse has been considered. The heat conduction in thin film has been described by two-temperature model consisting of the system of two coupled parabolic eąuations determining the electron and lattice temperatures. The sensitivity analysis of temperature fields with respect to the film thickness has been done. To this end the direct approach of shape sensitivity analysis using the concept of material derivative has been applied. The results of computations have been shown and the conclusions have been formulated.

3

Application of evolutionary algorithms for identification of dual phase lag model parameters

Mochnacki B., Paruch M.

Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej

|

2011

|

Vol. 10, nr 1

189-198

EN

The dual phase lag model (DPLM) based on the generalized form of Fourier law, in particular the introduction of two 'delay times' (relaxation time τq and thermalization time τT) leads to the considered form of energy equation. This equation should be applied in the case of microscale heat transfer modeling. In particular, DPLM constitutes a good approximation of thermal processes which are characterized by extremely short duration (e.g. ultrafast laser pulse), extreme temperature gradients and geometrical features of the domain considered (e.g. thin metal film). In this paper, the identification problem of two of the above mentioned positive constants τq, τT is discussed and the thermal processes proceeding in the domain of thin metal film subjected to a laser beam are analyzed. At the stage of computations connected with the identification problem solution, evolutionary algorithms are used. To solve the problem, additional information concerning the transient temperature distribution on a metal film surface is assumed to be known.

4

Two - temperature model of microscale heat transfer

Majchrzak E., Poteralska J.

Computer Methods in Materials Science

|

2011

|

Vol. 11, No. 2

330-336

EN

Thin metal film subjected to a short-pulse laser heating is considered. The hyperbolic two-temperature model describing the temporal and spatial evolution of the lattice and electrons temperatures is discussed. At a stage of numerical computations the finite difference method is used under the assumption that a part of thermophysical parameters in mathematical model of the process considered is temperature-dependent. In the final part of the paper the examples of computations are shown.

PL

Rozpatrywano cienką warstwę metalową poddaną działaniu lasera. Procesy cieplne w analizowanym obszarze opisano dwu-temperaturowym hiperbolicznym modelem, który uwzględnia zmiany temperatury elektronów i sieci krystalicznej. Zadaniel rozwiązano za pomocą metody różnic skończonych, przy czym uwzględniono zmienne z temperaturą wartości niektórych parametrów termofizycznych. W końcowej części artykułu przedstawiono wyniki obliczeń.

5

'One-shot' identification of laser intensity in a process of thin metal film heating

Majchrzak E., Mochnacki B., Poteralska J.

Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej

|

2009

|

Vol. 8, nr 1

131-136

EN

Thermal interactions between thin metal film and external laser pulse are considered. In particular on a basis of the knowledge of surface temperature distribution the laser intensity is estimated. The problem is described by dual-phase-lag model in which two relaxation parameters (relaxation time and thermalization time) are introduced in order to take into account the microscopic thermal interactions. The laser action is taken into account by additional term (source function) supplemented the basic energy equation. In the paper the mathematical model of the thin film heating process is discussed, the inverse problem is formulated and also the example of computations is presented.