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Wyświetlanie 1-8 z 8
Tytuł:
Implicit scheme of the finite difference method for the second-order dual phase lag equation
Autorzy:
Majchrzak, E.
Mochnacki, B.
Powiązania:
https://bibliotekanauki.pl/articles/280549.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
microscale heat transfer
dual phase lag model
implicit scheme of finite difference method
Opis:
The second-order dual phase lag equation (DPLE) as a mathematical model of the microscale heat transfer is considered. It is known that the starting point determining the final form of this equation is the generalized Fourier law in which two positive constants (the relaxation and thermalization times) appear. Depending on the order of the generalized Fourier law expansion into the Taylor series, different forms of the DPLE can be obtained. As an example of the problem described by the second-order DPLE equation, thermal processes proceeding in the domain of a thin metal film subjected to a laser pulse are considered. The numerical algorithm is based on an implicit scheme of the finite difference method. At the stage of numerical modeling, the first, second and mixed order of the dual phase lag equation are considered. In the final part of the paper, examples of different solutions are presented and conclusions are formulated.
Źródło:
Journal of Theoretical and Applied Mechanics; 2018, 56, 2; 393-402
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of dual phase lag model parameters using the evolutionary algorithms
Autorzy:
Mochnacki, B.
Paruch, M.
Powiązania:
https://bibliotekanauki.pl/articles/380526.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
microscale heat transfer
dual phase lag model
inverse problem
numerical modeling
przepływ mikroskalowy
model dwufazowy
zadanie odwrotne
model numeryczny
Opis:
Generalization of Fourier law, in particular the introduction of two ‘delay times’ (relaxation time τq and thermalization time τT) leads to the new form of energy equation called the dual-phase-lag model (DPLM). This equation should be applied in a 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 domain considered (e.g. thin metal film). The aim of considerations presented in this paper is the identification of two above mentioned positive constants τq, τT. They correspond to the relaxation time, which is the mean time for electrons to change their energy states and the thermalization time, which is the mean time required for electrons and lattice to reach equilibrium. In this paper the DPLM equation is applied for analysis of thermal processes proceeding in a thin metal film subjected to a laser beam. At the stage of computations connected with the identification problem solution the evolutionary algorithms are used. To solve the problem the additional information concerning the transient temperature distribution on a metal film surface is assumed to be known.
Źródło:
Archives of Foundry Engineering; 2011, 11, 3 spec.; 277-281
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Implicit scheme of the finite difference method for 1D dual-phase lag equation
Autorzy:
Majchrzak, E.
Mochnacki, B.
Powiązania:
https://bibliotekanauki.pl/articles/973620.pdf
Data publikacji:
2017
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
micro-scale heat conduction
dual-phase lag equation
finite difference method
stability of FDM implicit scheme
równanie z dwoma czasami opóźnień
metoda różnic skończonych
DPLE
schemat FDM
Opis:
The 1D dual-phase lag equation (DPLE) is solved using the implicit FDM scheme. The dual phase lag equation is the hyperbolic PDE and contains a second order time derivative and higher order mixed derivative in both time and space. The DPLE results from the generalization of the well known Fourier law in which the delay times are taken into account. So, in the equation discussed, two positive parameters appear. They correspond to the relaxation time τq and the thermalization time τ T. The DPLE finds, among others, the application as the mathematical description of the thermal processes proceeding in the micro-scale. In the paper, the numerical solution of DPLE based on the implicit scheme of the FDM is presented. The authors show that a such an approach in the case of DPLE leads to the unconditionally stable differential scheme.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2017, 16, 3; 37-46
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dual-phase lag equation. Stability conditions of a numerical algorithm based on the explicit scheme of the finite difference method
Autorzy:
Majchrzak, E.
Mochnacki, B.
Powiązania:
https://bibliotekanauki.pl/articles/122742.pdf
Data publikacji:
2016
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
heat conduction
dual-phase lag equation
finite difference method
stability conditions of FDM explicit scheme
przewodzenie ciepła
metoda różnic skończonych
Opis:
The dual-phase lag equation (DPLE) is considered. This equation belongs to the group of hyperbolic PDE, contains a second order time derivative and higher order mixed derivative in both time and space. From the engineer’s point of view, the DPLE results from the generalized form of the Fourier law. It is applied as a mathematical model of thermal processes proceeding in the micro-scale and also in the case of bio-heat transfer problem analysis. At the stage of numerical computations the different approximate methods of the PDE solving can be used. In this paper, the authors present the considerations concerning the stability conditions of the explicit scheme of finite difference method (FDM). The appropriate conditions have been found using the von Neumann analysis. In the final part of the paper, the results of testing computations are shown.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2016, 15, 3; 89-96
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dual Phase Lag Model of Melting Process in Domain of Metal Film Subjected to an External Heat Flux
Autorzy:
Mochnacki, B.
Ciesielski, M.
Powiązania:
https://bibliotekanauki.pl/articles/382640.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
theoretical basis
foundry process
solidification process
microscale heat transfer
dual phase lag model
control volume method
podstawy teoretyczne
proces odlewania
proces krzepnięcia
wymiana ciepła
model dwufazowy
Opis:
Heating process in the domain of thin metal film subjected to a strong laser pulse are discussed. The mathematical model of the process considered is based on the dual-phase-lag equation (DPLE) which results from the generalized form of the Fourier law. This approach is, first of all, used in the case of micro-scale heat transfer problems (the extremely short duration, extreme temperature gradients and very small geometrical dimensions of the domain considered). The external heating (a laser action) is substituted by the introduction of internal heat source to the DPLE. To model the melting process in domain of pure metal (chromium) the approach basing on the artificial mushy zone introduction is used and the main goal of investigation is the verification of influence of the artificial mushy zone ‘width’ on the results of melting modeling. At the stage of numerical modeling the author’s version of the Control Volume Method is used. In the final part of the paper the examples of computations and conclusions are presented.
Źródło:
Archives of Foundry Engineering; 2016, 16, 4; 85-90
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of relaxation and thermalization times in microscale heat transfer model
Autorzy:
Mochnacki, B.
Paruch, M.
Powiązania:
https://bibliotekanauki.pl/articles/279599.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
microscale heat transfer
laser heating
dual phase lag model
inverse problem
Opis:
The energy equation corresponding to the dual phase lag model (DPLM) results from the generalized form of the Fourier law, in which the two ‘delay times’ (relaxation and thermalization time) are introduced. The DPLM should be used in the case of microscale heat transfer analysis, in particular when thermal processes are characterized by extremely short duration (e.g. ultrafast laser pulse), considerable temperature gradients and very small dimensions (e.g. thin metal film). In this paper, the problem of relaxation and thermalization time identification is discussed, at the same time the heat transfer processes proceeding in the domain of a thin metal film subjected to a laser beam are analyzed. The solution presented bases on the application of evolutionary algorithms. The additional information concerning the transient temperature distribution on a metal film surface is assumed to be known. At the stage of numerical realization, the finite difference method (FDM) is used. In the final part of the paper, an example of computations is presented.
Źródło:
Journal of Theoretical and Applied Mechanics; 2013, 51, 4; 837-845
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Integro-differential form of the first-order dual phase lag heat transfer equation and its numerical solution using the Control Volume Method
Autorzy:
Ciesielski, M.
Mochnacki, B.
Majchrzak, E.
Powiązania:
https://bibliotekanauki.pl/articles/38606551.pdf
Data publikacji:
2020
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
micro-scale heat transfer
dual phase lag model
integro-differential equation
Control Volume Method
Opis:
The start point of the dual phase lag equation (DPLE) formulation is the generalized Fourier law in which two positive constants (the relaxation and thermalization times) appear. This type of equation can be used (among others) to describe the heat conduction processes proceeding in micro-scale. Depending on the number of components in the development of the generalized Fourier law into a power series, one can obtain both the first-order DPLE and the second-order one. In this paper the first-order dual phase lag equation is considered. The primary objective of this research is the transformation of DPLE differential form to the integro-differential one supplemented by the appropriate boundary-initial conditions. The obtained form of the differential equation is much simpler and more convenient at the stage of numerical computations – the numerical algorithm based on the three-time-level scheme reduces to the two-time-level one. To find the numerical solution, the Control Volume Method is used (the heating of thin metal film subjected to a laser beam is considered). The choice of the numerical method was not accidental. The method has a simple physical interpretation ensuring the preservation of the local and global energy balances. To our knowledge, it has not been used so far in this type of tasks. In the final part of the paper the examples of numerical simulations are presented and the conclusions are formulated.
Źródło:
Archives of Mechanics; 2020, 72, 5; 415-444
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of Melting and Resolidification in Domain of Metal Film Subjected to a Laser Pulse
Autorzy:
Majchrzak, E.
Mochnacki, B.
Powiązania:
https://bibliotekanauki.pl/articles/379913.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
foundry process
heat transfer
melting
solidification
dual phase lag model
numerical methods
theoretical basis
proces odlewniczy
przenikanie ciepła
topienie
krzepnięcie
model dwufazowy
metody numeryczne
podstawy teoretyczne
Opis:
Thermal processes in domain of thin metal film subjected to a strong laser pulse are discussed. The heating of domain considered causes the melting and next (after the end of beam impact) the resolidification of metal superficial layer. The laser action (a time dependent bell-type function) is taken into account by the introduction of internal heat source in the energy equation describing the heat transfer in domain of metal film. Taking into account the extremely short duration, extreme temperature gradients and very small geometrical dimensions of the domain considered, the mathematical model of the process is based on the dual phase lag equation supplemented by the suitable boundary-initial conditions. To model the phase transitions the artificial mushy zone is introduced. At the stage of numerical modeling the Control Volume Method is used. The examples of computations are also presented.
Źródło:
Archives of Foundry Engineering; 2016, 16, 1; 41-44
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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