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Wyszukujesz frazę "inverse heat transfer problem" wg kryterium: Temat


Wyświetlanie 1-11 z 11
Tytuł:
The inverse determination of volume fraction of fibres in reinforced composite with imperfect thermal contact between constituents
Odwrotne określenie objętościowego udziału włókien we wzmocnionym kompozycie z niedoskonałym kontaktem termicznym pomiędzy składnikami
Autorzy:
Mierzwiczak, M.
Kołodziej, J. A.
Powiązania:
https://bibliotekanauki.pl/articles/279324.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
effective thermal conductivity
inverse heat transfer problem
boundary collocation method
Newton method
Opis:
The paper considers the problem of determination of the volume fraction of fibres in an unidirectionally reinforced composite in order to provide the appropriate effective thermal conductivity. The problem formulated in such a way should be treated as an inverse heat transfer problem. The thermal conductivities of constituents (fibres and matrix) and fibres arrangement are known. The calculations are carried out for an imperfect thermal contact between the fibres and matrix.
W pracy rozważa się problem określenia objętościowego udziału włókien w jednokierunkowo wzmocnionym kompozycie w celu uzyskania odpowiedniego efektywnego współczynnika przewodzenia ciepła. Problem sformułowany w ten sposób jest traktowany jako odwrotny problem przewodzenia ciepła. Współczynniki przewodzenia ciepła składników (włókien i matrycy) oraz sposób ułożenia włókien są znane. Obliczenia są wykonane dla niedoskonałego kontaktu termicznego pomiędzy włóknami i matrycą.
Źródło:
Journal of Theoretical and Applied Mechanics; 2011, 49, 4; 987-1001
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulations of hardening and cooling of the early-age concrete
Autorzy:
Knor, G.
Powiązania:
https://bibliotekanauki.pl/articles/31343104.pdf
Data publikacji:
2013
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
concrete structures
inverse heat transfer problem
pipe cooling system
konstrukcje betonowe
wymiana ciepła
metody odwrotne
rurowy system chłodzenia
Opis:
The paper presents a new method of control, modeling and identification of thermal fields in concrete structures. The proposed methodology boils down to four interdependent tasks: 1) the determination of a time-dependent intensity of the heat of hardening and other thermophysical properties of concrete by means of the numerical inverse problem solution, which is based on experimental measurements of temperature, 2) numerical modeling of the evolution of the thermal field in the maturing concrete structure, using material properties determined in the first point, 3) experimental verification of a thermal field modeling (point 2) using 2D and 3D concrete samples, 4) the formulation of the problem of optimum design of the cooling system to mitigate thermal stress concentrations during maturing of massive concrete structures.
Źródło:
IPPT Reports on Fundamental Technological Research; 2013, 4; 11-18
2299-3657
Pojawia się w:
IPPT Reports on Fundamental Technological Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inverse heat transfer problem in digital temperature control in plate fin and tube heat exchangers
Autorzy:
Taler, D.
Sury, A.
Powiązania:
https://bibliotekanauki.pl/articles/240927.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
odwrotny przepływ ciepła
regulacja temperatury
wymiennik ciepła
digital PID control
heat exchanger
inverse heat transfer problem
model-based control
temperature control
Opis:
The aim of the paper is a steady-state inverse heat transfer problem for plate-fin and tube heat exchangers. The objective of the process control is to adjust the number of fan revolutions per minute so that the water temperature at the heat exchanger outlet is equal to a preset value. Two control techniques were developed. The first is based on the presented mathematical model of the heat exchanger while the second is a digital proportional-integral-derivative (PID) control. The first procedure is very stable. The digital PID controller becomes unstable if the water volumetric flow rate changes significantly. The developed techniques were implemented in digital control system of the water exit temperature in a plate fin and tube heat exchanger. The measured exit temperature of the water was very close to the set value of the temperature if the first method was used. The experiments showed that the PID controller works also well but becomes frequently unstable.
Źródło:
Archives of Thermodynamics; 2011, 32, 4; 17-32
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An inverse medium problem for the heat equation
Autorzy:
Maponi, P.
Powiązania:
https://bibliotekanauki.pl/articles/1954522.pdf
Data publikacji:
1999
Wydawca:
Politechnika Gdańska
Tematy:
differential equations
heat transfer equations
inverse problem
Opis:
In the article we consider the two-dimensional heat equation in a circular domain where the thermal diffusivity is a piecewise constant function in the radial directon and is a constant function in the angular direction. In particular we consider the problem of computation of a perturbation in this stratified medium having some information/knowledge about the temperature on the boundary of the domain due to heat flux applied to the same boundary. A linearized version of this inverse problem is considered and a linear integral equation is used for the numerical solution of the inverse problem. Some numerical examples are reported.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 1999, 3, 3; 277-292
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of the average and local boundary condition of heat transfer during cooling with a water spray under surface boiling
Autorzy:
Jasiewicz, Elżbieta
Hadała, Beata
Malinowski, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/29520235.pdf
Data publikacji:
2020
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
water spray cooling
heat transfer coefficient
heat flux
inverse problem
heat conduction equation
Opis:
The study determined the local and average heat transfer coefficient and the heat flux on the surface of a cylinder cooled with a water nozzle. The inverse method was used to identify the heat transfer coefficient. An objective function was defined to determine the distance between the measured and calculated temperatures. Two models describing the heat transfer coefficient on the cooled surface were considered. The first model described changes in the heat transfer coefficient as a function of the sample radius and cooling time, and the second one assumed the dependence of the heat transfer coefficient solely on time. Numerical simulations showed significant differences in the determined heat transfer coefficients depending on the adopted model of the boundary condition. The performed tests included experimental temperature measurements at selected points of the sensor, numerical simulations of temperature changes, and the inverse solution.
Źródło:
Computer Methods in Materials Science; 2020, 20, 4; 147-155
2720-4081
2720-3948
Pojawia się w:
Computer Methods in Materials Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wyznaczanie przewodności cieplnej materiałów tekstylnych przy użyciu termowizji
Thermal conductivity evaluation of textile materials using infrared measurements
Autorzy:
Felczak, M.
Michalak, M.
Więcek, B.
Powiązania:
https://bibliotekanauki.pl/articles/154532.pdf
Data publikacji:
2011
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
przewodzenie ciepła
odwrotne zagadnienia termiczne
termowizja
heat transfer
inverse heat conduction problem
Opis:
W pracy przedstawiono nową metodę wyznaczania parametrów termicznych materiałów włókienniczych, w tym także anizotropowych. Do próbek włókienniczych dostarczana jest energia cieplna i mierzona jest wartość temperatury po obu stronach materiału. Praca jest kontynuacją badań właściwości ciepłoizolacyjnych materiałów włókienniczych w dynamicznych warunkach za pomocą metody termograficznej w wykorzystaniem luster [1-6]. W stanowisku pomiarowym, którego schemat przedstawiono w cytowanych pracach zostało zastosowane źródło energii cieplnej umożliwiające szybkie nagrzewanie badanej próbki. Wykonano pomiary termowizyjne rozkładu temperatury i na podstawie uzyskanych wyników oraz modelowania termicznego wyznaczono przewodność cieplną badanych włóknin.
A new method for evaluation of homogenous anisotropic textiles thermal parameters is presented in this paper. The research is a continuation of investigating the thermal properties of textile materials [1-6]. The thermal energy was supplied to textile materials and the temperature distribution on both surfaces of the textile waas recorded using an infrared camera. The setup enabled fast textile heating. A thermal energy impulse was supplied to nonwovens. Using the obtained results and the finite element model of heat conduction, the thermal conductivity of a textile is evaluated. In order to obtain the thermal conductivity, it is necessary to solve an inversed heat conduction problem. The parameterized direct heat conduction model is used to calculate it. The research included both isotropic and anisotropic textile materials. The work was performed as a part of the Research Project 3 T08E 050 28 financed by KBN, entitled "3688/B/T02/2009/36 "The elaboration of the method of evaluation of temperature dependent thermal parameters of smart textile materials".
Źródło:
Pomiary Automatyka Kontrola; 2011, R. 57, nr 10, 10; 1223-1226
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
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:
The application of Beck’s method combined with FEM and Trefftz functions to determine the heat transfer coefficient in a minichannel
Autorzy:
Maciejewska, B.
Powiązania:
https://bibliotekanauki.pl/articles/281153.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
Beck’s method
FEM
Trefftz functions
heat transfer coefficient
inverse heat conduction problem
flow boiling
Opis:
The aim of this study is to determine the heat transfer coefficient between the heated surface and the boiling fluid flowing in a minichannel on the basis of experimental data. The calculation model is based on Beck’s method coupled with the FEM and Trefftz functions. The Trefftz functions used in the Hermite interpolation are employed to construct the shape functions in the FEM. The unknown local values of the heat transfer coefficient at the foil- -fluid contact surface are calculated from Newton’s law. The temperature of the heated foil and the heat flux on the foil surface are determined by solving a two-dimensional inverse heat conduction problem. The study is focused on the identification of the heat transfer coefficients in the subcooled boiling region and the saturated nucleate boiling region. The results are compared with the data obtained through the one-dimensional method. The investigations also reveal how the smoothing of measurement data affects calculation results.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 1; 103-116
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement of heat flux density and heat transfer coefficient
Autorzy:
Taler, D.
Taler, J.
Grądziel, S.
Powiązania:
https://bibliotekanauki.pl/articles/240288.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
pomiar temperatury
strumień ciepła
współczynnik przenikania ciepła
zagadnienie odwrotne
heat flux
heat transfer coefficient
inverse problem
temperature measurement
Opis:
The paper presents the solution to a problem of determining the heat flux density and the heat transfer coefficient, on the basis of temperature measurement at three locations in the flat sensor, with the assumption that the heat conductivity of the sensor material is temperature dependent. Three different methods for determining the heat flux and heat transfer coefficient, with their practical applications, are presented. The uncertainties in the determined values are also estimated.
Źródło:
Archives of Thermodynamics; 2010, 31, 3; 3-18
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An analytical method for solving the two-phase inverse Stefan problem
Autorzy:
Hetmaniok, E.
Słota, D.
Wituła, R.
Zielonka, A.
Powiązania:
https://bibliotekanauki.pl/articles/200444.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Inverse Stefan problem
homotopy analysis method
heat transfer
solidification
przepływ ciepła
krzepnięcie
homotopijna metoda analizy
Opis:
In the paper we present an application of the homotopy analysis method for solving the two-phase inverse Stefan problem. In the proposed approach a series is created, having elements which satisfy some differential equation following from the investigated problem. We reveal, in the paper, that if this series is convergent then its sum determines the solution of the original equation. A sufficient condition for this convergence is formulated. Moreover, the estimation of the error of the approximate solution, obtained by taking the partial sum of the considered series, is given. Additionally, we present an example illustrating an application of the described method.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2015, 63, 3; 583-590
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
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
    Wyświetlanie 1-11 z 11

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