Wyniki wyszukiwania - BazTech

1

Simplified model of thermal interactions between environment, protective clothing and skin tissue

Mochnacki B., Majchrzak E., Duda M.

Journal of Applied Mathematics and Computational Mechanics

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2014

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Vol. 13, nr 4

91--96

EN

In the paper the simplified model of thermal processes proceeding in the domain of biological tissue secured with protective clothing is discussed. In particular, the simplification of the mathematical model consists in the omission of the real layer of fabric for which the transient temperature field is determined by the Fourier equation and the introduction in this place of the additional thermal resistance appearing in the boundary condition determining the heat exchange between tissue and environment. In this way both the mathematical model of the thermal processes in the system considered and also numerical realization are greatly simplified. To verify the effectiveness of the approach proposed, the solution of the basic problem and the simplified one have been solved (1D task) using the finite difference method and the results have been compared. It turned out that the results are close and from the practical point of view such simplification is fully acceptable.

2

Numerical simulation of the heating process in the domain of tissue insulated by protective clothing

Ciesielski M., Mochnacki B.

Journal of Applied Mathematics and Computational Mechanics

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2014

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Vol. 13, nr 2

13--20

EN

In this paper the 2D heterogeneous tissue domain (forearm cross-section) insulated by a layer of protective clothing is considered. The aim of considerations is to develop an algorithm simulating the tissue heating process resulting from the sudden change of external boundary conditions. Here, the authors exploit a certain version of the control volume method (CVM) using the Voronoi tessellation. The mathematical model of heat exchange in the domain analyzed is formulated in the form of a boundary-initial problem based on the system of partial differential equations (energy equations) supplemented by the adequate boundary and initial conditions. In the final part of the paper, the examples of numerical simulations are shown.

3

Numerical modeling of thermal processes in the living tissue domain secured with a layer of protective clothing

Mochnacki B., Majchrzak E., Duda M.

Journal of Applied Mathematics and Computational Mechanics

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2014

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Vol. 13, nr 1

87--94

EN

In the paper the problem of thermal processes proceeding in the domain of biological tissue secured with protective clothing is discussed. In particular, the mathematical model of heat exchange corresponding to conditions of high temperature in the system environment - layer of protective clothing - air gap - skin tissue is formulated in the form of a certain boundary - initial problem. Next, the numerical algorithm based on the boundary element method is presented. In the final part of the paper the examples of numerical simulations are shown.

4

Eksploatacja technicznych obiektów budowlanych w aspekcie przejścia ciepła przez przegrody

Janczarek M.

Postępy Nauki i Techniki

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2011

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nr 9

112-124

PL

Artykuł zawiera analizę przejścia ciepła przez przegrodę zewnętrzną technicznego obiektu budowlanego z uwzględnieniem wpływu zmiennej temperatury atmosferycznej na temperaturę wewnętrzną komory. Poprzez odpowiednie wykorzystanie wpływu sinusoidalnych zmian zewnętrznej temperatury w postaci przesunięcia fazowego wektora strumienia ciepła do wnętrza pomieszczenia uzyskano tłumienie oscylacji temperatury obiektu budowlanego, które pozwala obniżyć koszty energii zużywanej na utrzymywanie określonych warunków cieplnych w pomieszczeniu.

EN

This paper describes research work on methods concerning heat transfers through walls of thermal technical chambers. The paper presents the analysis of complex problems in the field of energy savings and material selection during long term storage of fruit in thermal chambers in controlled gaseous environment. The purpose for the research is to point out areas subjected to the highest energy losses caused by building's construction and geographical orientation of walls in the aspect of daily atmospheric temperature changes emerging on chamber exterior. The paper is focused on the new concept of thermal analysis derived from harmonic character of temperature changes in building environment - especially in fruit storages - with aspect on conductive heat transfers through walls. This changeable influence of variable weather temperature on internal temperature of technical chamber depends on thermal inertia of building.

5

Modelowanie przenikania ciepła przez przegrode zewnetrzną komory cieplnej

Janczarek M. M., Skalski P.

Rynek Energii

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2000

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nr 1

27-30

PL

Przedstawiono metodę modelowania przenikania ciepła przez przegrodę komory technicznej przy pomocy pełnego równania Fouriera dla różnych warunków brzegowych i początkowych. Przykładowo wyznaczono temperatury powierzchni zewnętrznych przegrody oraz temperaturę wewnątrz tej przegrody.

EN

Variation of external air temperature, which is changing from the hot one by day to the cold one by night, has an effect on the internal temperature, which depends on the conductive heat transfer through the walls of thermal technical spaces. By the suitable construction of the enclosure walls composed of several slabs of different thickness and conductivities we can obtain a phase angle displacement (when the time lag attains twelve hours it is the best situation), which reduces the amplitude of internal temperature inside buildings. This paper describes the development of methods and research work concerning conductive heat transfers through the walls of thermal technical spaces. The issue of thermal conductivity is treated by a large number of methods, for example: Laplace transformations method, Fourier transforms, etc. In our work we found two models: analogous and differential, with the help of them it is possible to establish control of heat processes in thermal technical spaces.