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1

Chemically reacting Jeffrey fluid flow over a deformable porous layer with entropy generation analysis

Das Utpal Jyoti

International Journal of Applied Mechanics and Engineering

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2022

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Vol. 27, no. 3

36--48

EN

Entropy generation of a steady Jeffrey fluid flow over a deformable vertical porous layer is analysed with consideration of a first-order chemical reaction and thermal diffusion. The porous material is modelled as a homogeneous binary mixture of fluid and solid phases where each point in the binary mixture is occupied concurrently by the fluid and solid. The combined phenomenon of solid deformation and fluid movement is taken into account. The impact of relevant parameters on the fluid velocity, solid displacement, temperature and concentration profiles is discussed. It is noticed that the Jeffrey fluid parameter enhances the entropy generation number, fluid velocity and solid displacement profiles, but a reverse effect is seen for the Bejan number. Further, entropy generation, fluid velocity and solid displacement reduce due to the higher estimates of the chemical reaction parameter, while the Bejan number enhances.

2

Influence of thermal diffusion on MHD radiating flow in presence of Cu-nanoparticles, Casson fluid and angle of inclination

Brahma-Chary S., Jayarami-Reddy K., Kashaiah K.

Journal of Applied Mathematics and Computational Mechanics

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2020

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Vol. 19, nr 2

43--58

EN

In this study numerical solutions for magnetohydrodynamic transfer, thermal and mass instability, free convection flow through the plate before Casson fluid, heat dissipation, thermal radiation, heat sink, chemical reaction, tilt angle, and saturated porous medium were described. The effectiveness of this study is to analyze the effect of heat diffusion, Casson fluid, the angle of interest on the flow phenomenon of Cu-nanoparticles in the presence of thermal radiation, heat source/heat sink, destructive reaction, heat transfer and mass transfer in a simple way. The finite difference method was used to solve the governing equations which are the added partial differential equations. The effects of different material parameters on velocity, temperature and concentration profiles are explained using graphs and tables. The results are compared with previously published papers and a very good agreement is found. In the boundary layer region, fluid velocity decreases with the increasing values of magnetic field parameter, heat source/sink, Casson fluid, angle of inclination and thermal radiation parameter for Cu-nanoparticles. Also it is noticed that the solutal boundary layer thickness decreases with an increase in the chemical reaction parameter. It is because chemical molecular diffusivity reduces for higher values of Kr.

3

Thermo-diffusion of a thick circular plate via modified Green–Naghdi models

Zenkour A. M.

Archives of Mechanics

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2020

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Vol. 72, nr 3

235--256

EN

This article presents the thermo-diffusion of an isotropic thick circular plate. The Green and Naghdi’s models including the energy dissipation are anticipated in their simple forms. Novel multi single/dual-phase-lag models with higher-order timederivatives are also provided to examine the thermo-diffusion response of the circular plate. The simple and refined forms of Green and Naghdi’s types II and III are investigated in this work. The closed-form solution of thermal diffusion governing equations is attained by taking into account the boundary conditions. A validation examples of outcomes are acceptable by comparing all quantities according to the discussing of all thermoelastic models. The refined forms of Green and Naghdi’s types II and III should be applied to get accurate outcomes.

4

Unsteady MHD thermal diffusive and radiative fluid flow past a vertical porous plate with chemical reaction in slip flow regime

Ravi Kumar D., Jayarami Reddy K., Raju M. C.

International Journal of Applied Mechanics and Engineering

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2019

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Vol. 24, no. 1

117--129

EN

An analytical solution of an MHD free convective thermal diffusive flow of a viscous, incompressible, electrically conducting and heat-absorbing fluid past a infinite vertical permeable porous plate in the presence of radiation and chemical reaction is presented. The flow is considered under the influence of a magnetic field applied normal to the flow. The plate is assumed to move with a constant velocity in the direction of fluid flow in slip flow regime, while free stream velocity is assumed to follow the exponentially increasing small perturbation law. The velocity, temperature, concentration, skin friction, Nusselt number and Sherwood number distributions are derived and have shown through graphs and tables by using the simple perturbation technique.

5

Numerical solutions by EFGM of MHD convective fluid flow past a vertical plate immersed in a porous medium in the presence of cross diffusion effects via biot number and convective boundary condition

Raju R. S., Reddy B. M., Rashidi M. M., Gorla R. S. R.

International Journal of Applied Mechanics and Engineering

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2017

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Vol. 22, no. 3

613--636

EN

In this investigation, the numerical results of a mixed convective MHD chemically reacting flow past a vertical plate embedded in a porous medium are presented in the presence of cross diffusion effects and convective boundary condition. Instead of the commonly used conditions of constant surface temperature or constant heat flux, a convective boundary condition is employed which makes this study unique and the results more realistic and practically useful. The momentum, energy, and concentration equations derived as coupled second-order, ordinary differential equations are solved numerically using a highly accurate and thoroughly tested element free Galerkin method (EFGM). The effects of the Soret number, Dufour number, Grashof number for heat and mass transfer, the viscous dissipation parameter, Schmidt number, chemical reaction parameter, permeability parameter and Biot number on the dimensionless velocity, temperature and concentration profiles are presented graphically. In addition, numerical results for the local skin-friction coefficient, the local Nusselt number, and the local Sherwood number are discussed through tabular forms. The discussion focuses on the physical interpretation of the results as well as their comparison with the results of previous studies.

6

Influence of soret effect on mhd mixed convection flow of visco-elastic fluid past a vertical surface with hall effect

Jha A. K., Choudhary K., Sharma A.

International Journal of Applied Mechanics and Engineering

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2014

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Vol. 19, no. 1

79--95

EN

The present paper deals with the unsteady motion of an MHD free convection flow of an incompressible non- Newtonian viscoelastic fluid past an infinite vertical plate in the presence of a heat source and Soret effect. A parametric study illustrating the influence of various parameters on the temperature, velocity as well as on the skin-friction and rate of heat transfer is conducted. The results of the effect of the magnetic field, the parameter describing the non-Newtonian behavior, and the velocity of suction and injection on both the velocity and temperature distributions are examined and shown graphically.

7

Anemometr z falą cieplną – generowanie i analiza sygnału

Ligęza P., Kiełbasa J., Poleszczyk E., Rachalski A., Socha K., Palacz J.

Prace Instytutu Mechaniki Górotworu PAN

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2013

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Vol. 15, no. 1-2

41--45

PL

Przedstawiono badania anemometru z falą cieplną, w którym źródło fali jest sygnałem posiadającym kilka dominujących składowych harmonicznych. Zastosowano sygnał będący sumą sygnałów sinusoidalnych oraz sygnał prostokątny typu MBS (Multifrequency Binary Sequences). Przedstawiono wyniki pomiarów prędkości przepływu i dyfuzyjności cieplnej powietrza w zakresie prędkości 5-50 cm/s.

EN

Testing is done on a thermal wave anemometer in which the wave source is a signal composed of several dominant harmonics. The signal applied was the sum of the sine signal and the square signal of the MBS type. The results of flow velocity and air diffusion measurements were taken in the velocity range 5-50 cm/s.

8

MHD natural convection flow with radiative heat transfer past an impulsively moving vertical plate with ramped temperature in the presence of hall current and thermal diffusion

Seth G. S., Mahato G. K., Sarkar S.

International Journal of Applied Mechanics and Engineering

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2013

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Vol. 18, no. 4

1201--1220

EN

An investigation on an unsteady MHD natural convection flow with radiative heat transfer of a viscous, incompressible, electrically conducting and optically thick fluid past an impulsively moving vertical plate with ramped temperature in a porous medium in the presence of a Hall current and thermal diffusion is carried out. An exact solution of momentum and energy equations, under Boussinesq and Rosseland approximations, is obtained in a closed form by the Laplace transform technique for both ramped temperature and isothermal plates. Expressions for the skin friction and Nusselt number for both ramped temperature and isothermal plates are also derived. The numerical values of fluid velocity and fluid temperature are displayed graphically versus the boundary layer coordinate y for various values of pertinent flow parameters for both ramped temperature and isothermal plates. The numerical values of the skin friction due to primary and secondary flows are presented in tabular form for various values of pertinent flow parameters.

9

Analysis of Selected Physical Properties of Membrane Fabrics Influencing the Utility Comfort of Clothing

Frydrych I., Sybilska W., Wajszczyk M.

Fibres & Textiles in Eastern Europe

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2009

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Vol. 17, no. 6 (77)

50--56

EN

By carrying out measurements of the thermoinsulation properties of clothing materials, we can obtain a lot of valuable information regarding the wide characteristics of these materials. Knowing thermoinsulation property values of clothing material, we can start the proper designing of thermoinsulation clothing by selecting and combining fabrics in such a way that we obtain clothing of very good thermal properties. In this paper the results of evaluation of the thermoinsulation parameters of membrane fabrics are presented. Measurements were carried out for 12 different clothing materials with half-permeable membranes for the inner as well as for the outer side of the material. An analysis of results is given.

PL

Przeprowadzając badania właściwości ciepłochronnych materiałów odzieżowych, które sprowadzają się głównie do określenia parametrów izolacyjności cieplnej można uzyskać dużo cennych informacji, które razem tworzą szeroką charakterystykę tych materiałów. Znając wartości parametrów izolacyjności cieplnej materiałów odzieżowych można rozpocząć dopiero wtedy prawidłowe projektowanie odzieży ciepłochronnej dobierając i łącząc materiały tak, aby razem tworzyły odzież o bardzo dobrych właściwościach cieplnych. W artykule przedstawiono wyniki badań parametrów termoizolacyjności cieplnej wyrobów membranowych. Badania wykonano za pomocą przyrządu Alambeta w klimacie normalnym. Parametry termoizolacyjności cieplnej mierzono dla 12 różnych materiałów odzieżowych z membranami półprzepuszczalnymi zarówno dla strony prawej, jak i dla lewej.

10

Investigation of the Thermal Insulation Properties of Multilayer Textiles

Matusiak M.

Fibres & Textiles in Eastern Europe

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2006

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Vol. 14, no. 5 (59)

98--102

EN

Assuring the thermal stability of the human body is one of the most important functions of the clothing. Clothing creates a barrier between the skin surface and surroundings. This barrier influences not only the heat exchange by convection and radiation, but also the heat exchange by the evaporation of excreted sweat. The influence of clothing on the heat exchange between the human being and their surroundings is very complex. It depends on many factors connected with the environment, i.e. air temperature, air movement and humidity. No less an important role is played by the raw material, as well as the micro- and macrostructure of clothing. The aim of this work is to investigate the thermal insulation properties of the single- and multilayer textile materials. The thermal properties were measured with an Alambeta device. We investigated the relationships between the thermal insulation properties of the set of materials and the parameters of the particular components of sets, as well as the configuration of layers.

PL

Jedną z głównych funkcji odzieży jest zapewnienie stabilności termicznej organizmu użytkownika. Odzież wpływa na wymianę ciepła pomiędzy organizmem a otoczeniem, nie tylko poprzez przewodzenie, konwekcję, czy promieniowanie, lecz również poprzez odprowadzanie potu. Wpływ odzieży na wymianę ciepła jest bardzo złożony i zależy od wielu czynników. W artykule przedstawiono badania właściwości termoizolacyjnych materiałów włókienniczych jedno- i wielowarstwowych. Badania przeprowadzono za pomocą przyrządu Alambeta. W oparciu o uzyskane wyniki, przeanalizowano zależności pomiędzy wartościami wybranych właściwości termicznych wielowarstwowych układów materiałów: tkanin i włóknin, a właściwościami termoizolacyjnymi poszczególnych warstw układu.

11

Radiation and thermal diffusion effects on MHD unsteady Maxwell fluid past a porous flat through porous medium

Eldabe N. T. M., Hassan A. A. A, Ghaly A. Y.

Mechanics and Mechanical Engineering

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2004

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Vol. 7, nr 2

153-163

EN

Radiation and thermal diffusion effects of magnetohydrodynamic flow for non Newtonian fluid through a porous medium past an infinite porous flat plate arc presented. The flow under consideration obeys Maxwell rheological model. Solutions for velocity, temperature and concentration distributions arc obtained with the help of finite difference method. The effects of various parameters such as relaxation parameter λ of the Maxwell fluid, permeability of the fluid K, magnetic parameter M, Dufour number Df, Soret number Sr, Prandtl number Pr, radiation parameter N and Schmidt number Sc on the velocity, temperature and concentration profiles are studied and illustrated graphically. We obtained also the rate of heat transfer and concentration gradient during the course of discussion.

12

Effects of chemical reaction, heat and mass transfer on nonlinear boundary layer flow with heat source, thermal diffusion in the presence of suction

Kandasamy R.

International Journal of Applied Mechanics and Engineering

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2004

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Vol. 9, no 2

325-332

EN

The problem concerns a nonlinear laminar boundary layer, chemical reaction, heat and mass transfer flow of an incompressible and viscous fluid past a continuously moving infinite vertical porous plate in the presence of suction under the influence of heat source and thermal diffusion. The similarity transformation has been utilized to convert the governing nonlinear partial differential equations into nonlinear ordinary differential equations and then the numerical solution to the problem is given using the Gill method. The analysis of this results obtained shows that the flow field is influenced appreciably by the presence of suction at the surface, chemical reaction and magnetic effects.

13

Thin dielectric electrodiffusion masks for Ag+ - Na+ ion exchange applications

Mrozek E., Mrozek P.

Journal of Technical Physics

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2003

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Vol. 44, no 3

289-294

EN

A new method of thin dielectric mask preparation for Ag+ - Na+ ion exchange applications was developed. Electrodiffusion bonding of Al-film to glass was used to obtain very thin dielectric Al2O3 layer in the Al-glass transition zone. After Al removal, the quality of the dielectric mask was tested in Ag pure thermal diffusion and electrodiffusion processes in molten AgNO3.

14

On the modified Fick law and its potential applications

Piekarski S.

Journal of Technical Physics

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2003

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Vol. 44, no 2

125-131

EN

It can be observed that the standard Einstein-Smoluchowski equation for isothermal processes can be written in the two equivalent forms which, however, become distinct when the temperature becomes spatially varying. Therefore, we have two different equations which could potentially describe the flux of diffusing particles subjected to the potential external forces and variable temperature. The first is the standard Einstein-Smoluchowski equation, while the second is its modification containing an additional term proportional to the temperature gradient. In order to fix the terminology, the above mentioned modification of standard Einstein-Smoluchowski equation shall be called '^the modified Fick law". In this paper, we shall discuss the origin of this equation and we shall try to make a preliminary discussion of its solutions and potential applications to thermodiffusion. We propose two models: one exploiting Onsager's thermodynamics and the second one independent from it. Elementary solutions of both models are identical in the limit of small concentrations.

15

On diffusion and thermodiffusion in a gravity field

Piekarski S.

Journal of Technical Physics

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2003

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Vol. 44, no 3

329-337

EN

The modified Fick law has been introduced in the paper: S. Piekarski, On the modified Fick law and its potential applications (J. Tech. Phys., 44, 2, 125-131, 2003). The first purpose of the present paper is to give a simpler "derivation" of the modified Fick law than that originally presented. Namely, it can be introduced as a particular case of the Wojnar equation (R. Wojnar, "Nonlinear heat equation and thermodiffusion", p. 296, Eq. (2.1), Rep. on Math. Phys., No 1/2, Vol. 46, 2000). The third equation discussed is the Einstein-Smoluchowski equation. All equations mentioned above, contain a potential for the force, acting on the diffusing matter. The important fact is that, for isothermal conditions, all the equations mentioned above are identical. In this article we try to describe the effects of the constant gravitational field on the diffusion processes. We propose an explicit form of the potential for which the equilibrium concentration profiles are consistent with the experimental results. We compare shortly our results with two models of the diffusion processes in a gravitational field described in Huang's book [8] as well as with other opinions concerning this subject. As an example of technological application of the presented theory, the diffusion of the atomic hydrogen in fluid iron is proposed.

16

Numerical study on extraction of tritium generated in HMR by way of system composed of EXEL-process and thermal diffusion column cascade

Shimizu M., Takeshita K.

Nukleonika

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2002

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Vol. 47,suppl.1

89-93

EN

A new tritium extraction system composed of a trickle-bed hydrogen/water isotopic exchange column using a hydrophobic Pt-catalyst combined with an SPE-water electrolyser (EXEL-process) and a thermal diffusion column cascade was proposed for the removal of tritium from heavy water irradiated in HMR ((Heavy Water Moderated Power Reactor), volume of heavy water = 140 m3 and mean neutron flux = 5×1013 n/cm2s). Numerical study on the extraction of tritium from the heavy water was carried out and the dimensions of proposed system were determined under the conditions that the concentration of tritium in the heavy water was kept less than 2.5 Ci/lHW. The calculation results indicated that the proposed system was designed practically.

17

Comparative Analysis of the Thermal Insulation Properties of Fabrics Made of Natural and Man-Made Cellulose Fibres

Frydrych I., Dziworska G., Bilska J.

Fibres & Textiles in Eastern Europe

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2002

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Vol. 8, no. 4 (39)

40--44

EN

Yarn made of natural and man-made cellulose fibres is nowadays commonly applied in textiles. It is already apparent that the type of raw material and fabric structure influences the properties of the finished goods. The main aim of this paper was to present a comparative analysis of thermal insulation properties (such as thermal conductivity, absorption and thermal resistance) of fabrics made of cotton and Tencel. 6 samples of cotton fabrics and 9 samples of fabrics from Tencel yarns were produced for the purpose of these tests. All fabrics had warp and weft yarns of nominal linear density of 20 tex. Three kinds of weaves were applied: plain, combined and twill with nominal warp and weft densities of 320/dm. The measurements were carried out on finished fabrics with the use of the ALAMBETA device. The results are presented graphically and discussed. The finished fabrics made of Tencel yarn showed lower values of thermal conductivity and thermal absorption than fabrics made of cotton yarns, and higher values of thermal diffusion and resistance. The influence of the type of weave on thermal properties was observed for all fabrics made of cotton and Tencel.

PL

Przędze z naturalnych i sztucznych włókien celulozowych są współcześnie powszechnie stosowane w tekstyliach. Jest oczywiste, że typ surowca i struktura wyrobu wpływają na właściwości gotowych produktów. Celem badań było przeprowadzenie analizy porównawczej właściwości termoizolacyjnych (takich jak przewodność cieplna, absorpcja i oporność termiczna) tkanin wykonanych z bawełny i włókna Tencel. Dla celów tego testu wyprodukowano 6 próbek tkanin bawełnianych i 9 z przędzy Tencel. We wszystkich tkaninach stosowano osnowę i wątek o masie liniowej 20 tex. Stosowano 3 typy splotów: prosty (płócienny), kombinowany i skośny, przy nominalnej wartości gęstości osnowy i wątku 320/dm. Pomiary przeprowadzono na tkaninach wykończonych, za pomocą przyrządu ALAMBETA. Wyniki przedstawiono w artykule graficznie i przedyskutowano. Gotowe tkaniny wykonane z włókien Tencel mają niższe wartości termicznej przewodności i absorpcji niż tkaniny bawełniane, a wyższe wartości termicznej dyfuzji i oporności. Zaobserwowano wpływ rodzaju splotu na właściwości termiczne dla wszystkich tkanin wykonanych z bawełny i włókien Tencel.

18

Wyznaczanie przewodności i dyfuzyjności cieplnej ciał stałych za pomocą metody algorytmów genetycznych

Kucypera S. S.

Zeszyty Naukowe Katedry Mechaniki Stosowanej / Politechnika Śląska

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2001

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z. 17

95-100

PL

W pracy przedstawiono sposób wyznaczania przewodności i dyfuzyjności cieplnej ciał stałych przy pomocy metody szeregów Fouriera i metody algorytmów genetycznych. Szeregi Fouriera zastosowano do rozwiązania bezpośredniego zagadnienia przewodzenia ciepła i wyznaczenia rozkładu temperatury w próbkach. W celu wyznaczenia przewodności i dyfuzyjności cieplnej ciał stałych zagadnienie odwrotne sformułowano jako problem optymalizacyjny. Zagadnienie optymalizacyjne rozwiązano metodą algorytmów genetycznych Przedstawiono przykładowe wyniki badań.

EN

The way of determination of the thermal conductivity and thermal diffusivity of a solid bodies by applied series Fourier method and method of genetic algorithms has been presented in this paper. A series Fourier method was applied to solve a direct heat conduction problem and calculation the distribution of temperature within domain of samples. In order to determine the thermal conductivity and thermal diffusivity of body the inverse problem was formulated as an optimisation problem. The optimisation problem was solved by using the genetic algorithms method. The sample results of a researches have been presented.

19

Application of the BEM for numerical simulation of non-steady thermal diffusion in cylindrical domains

Majchrzak E., Dziewoński M.

Zeszyty Naukowe Katedry Mechaniki Stosowanej / Politechnika Śląska

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1999

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z. 10

209-214

EN

In the paper the boundary element method is used for numerical simulation of non-steady heat conduction in domains oriented in cylindrical coordinate system. The starting point of considerations is 3D problem, for which of fundamental solution is known. This function allow to determine the fundamental solution in a case of cylindrical domain. The first scheme of the BEM is applied in order to construct the numerical algorithm. In the final part of the paper the example of numerical computation is shown.

PL

W pracy wykorzystano metodę elementów brzegowych do numerycznej symulacji nieustalonego przewodzenia ciepła w obszarach zorientowanych w walcowym układzie współrzędnych. Punktem wyjściowym rozważań jest zadanie przestrzenne, dla którego znane jest rozwiązanie fundamentalne. Funkcja ta pozwala określić rozwiązanie fundamentalne dla obszarów walcowych. Przy tworzeniu algorytmu numerycznego zastosowano tzw. pierwszy schemat MEB. W końcowej części artykułu przedstawiono wyniki dla obliczeń testujących.