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1

Thermal analysis of concrete structures in fire situation

Chudyba Krzysztof

Materiały Budowlane

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2025

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nr 2

1--8

EN

The paper presents the questions of thermal analysis of concrete structures in fire situation. There are described general rules as well as practical methods for conductiong thermal analysis. The basic recommendations and detailed informations included within this scope in the new code for fire design are also discussed, with special attention paid to the differences in comparison with the present code PN-EN 1992-1-2.

PL

W artykule przedstawiono zagadnienie analizy termicznej konstrukcji z betonu w warunkach oddziaływania pożarowego. Podano ogólne zasady prowadzenia takiej analizy, a także opisano możliwe praktyczne sposoby jej realizacji. Skomentowano zalecenia i szczegółowe informacje zawarte w nowej normie do projektowania konstrukcji z betonu na warunki pożarowe, przedstawiając różnice w porównaniu z obecną normą PN-EN 1992-1-2.

2

Prediction of the residual stress-strain state of butt and tee joints of Al-Mg-Mn aluminium alloy produced by consumable electrode pulse-arc welding

Gao Shiyi, Korzhyk Volodymyr, Liu Zhe, Khaskin Vladyslav, Zhao Yunqiang, Illiashenko Yevhenii, Alyoshin Andriy, Kvasnytskyi Viktor, Perepichay Andrii, Prokhorenko Odarka

Advances in Science and Technology. Research Journal

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2025

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Vol. 19, no. 4

311--328

EN

Assessment of the residual stress-strain state (SSS) at MIG welding of aluminium alloys structures is relevant, because of the need to predict formation of residual stresses and strains, which may lead to lowering of fatigue strength of such a structure. Therefore, the research is devoted to determination of the influence of the mode of pulse-arc (MIG) welding of 1561 aluminium alloy of Al-Mg-Mn system (4 mm thickness) on the thermal cycle of the process and prediction of the influence of rigid restraint of the welded specimens in the assembly-welding fixture on the residual SSS of butt and tee welded joints. For this purpose, a finite element model of calculation of the temperature fields and SSS was created on the base of the conduced technological studies, which ensured up to 10% accuracy, that is an acceptable result for technological calculations. This model was used to determine the longitudinal and transverse tensile stresses and displacements, equivalent strains and stresses, out-of-plane displacements of the welded joint of Al-Mg-Mn aluminium alloy. It was found that rigid restraint of the specimens leads to formation of maximal equivalent stresses at MIG welding: for the butt joint - up to 190 MPa, forming in the points of transition from the weld to the base metal on the face surface; for the tee joint - ~250-260 MPa, forming in the weld area in the flange. Out-of-plane displacement after unfastening of the welded specimens from the assembly-welding fixture was equal to: for butt joint – up to 0.1 mm; for tee joint – up to formation of a plastic zone in the flange ~1.7 times larger than in the web, and out-of-plane bending of the web by 1.31 mm.

3

Numerical Modeling of Thermal Energy Flow Compared with Data Obtained from an Experiment

Chodór Jarosław, Chomka Grzegorz, Orłowska Magdalena

Rocznik Ochrona Środowiska

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2024

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Tom 26

403--412

EN

The article presents the results of numerical analyses of temperature distribution and heat flow distribution in the building partition. The analysis results were compared with the results of the real object. A very good convergence of the results was observed.

4

Wyznaczenie rozkładu temperatur w warstwach wymurówki pieca szybowego z pionową lancą TSL

Kolczyk Ewa

Przemysł Chemiczny

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2024

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T. 103, nr 11

1252--1255

PL

Opracowano model przepływu ciepła dla instalacji pilotowej pieca szybowego TSL. Pozwolił on wyznaczyć na różnych poziomach pieca rozkład temperatur na jego ścianach i jego spodzie, uwzględniając rodzaj materiałów i grubość warstw wymurówki. Temperatura poszczególnych warstw wykładzin w funkcji odległości od zewnętrznej ściany pieca badana na różnych poziomach miała charakter wzrostowy. Najwyższe temperatury warstw wykładzin występowały na poziomie ciekłej kąpieli. Najniższe temperatury odnotowano na poziomie sklepienia pieca. Wysokie temperatury występowały również w warstwach wykładzin znajdujących się na spodzie pieca.

EN

A heat flow model was developed for the pilot installation of a TSL shaft furnace. It allowed to det. the temp. distribution on the furnace walls and its bottom at different levels of the furnace, taking into account the type of materials and the thickness of the lining layers. The temp. of individual lining layers as a function of the distance from the external wall of the furnace, examined at various levels, was increasing. The highest temp. of the lining layers occurred at the level of the liquid bath. The lowest temp. were recorded at the level of the furnace vault. High temp. also occurred in the lining layers at the bottom of the furnace.

5

Połączenia dachowych płyt warstwowych w aspekcie zagadnień cieplno-wilgotnościowych

Krause Paweł, Pawlak-Jakubowska Anita

Materiały Budowlane

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2024

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nr 1

43--46

6

Modelowanie numeryczne rozkładu temperatury w kwadratowych przekrojach żelbetowych ogrzewanych z czterech stron w warunkach pożaru wraz z wyznaczeniem położenia izotermy 500°C oraz temperatury zbrojenia

Maciąg Michał

Inżynieria i Budownictwo

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2024

|

R. 80, nr 7

462--466

PL

W artykule przeprowadzono szereg symulacji nieustalonego przepływu ciepła w elementach żelbetowych ogrzewanych z czterech stron. Przebadano wybrane przekroje kwadratowe o długości boku od 16 do 40 cm. Przyjęto ogrzewanie elementów wg krzywej standardowej pożaru w czasie od 0 do 240 min. W pracy zbadano temperaturę przekroju w odległości a = 2, 4, 6, 8 cm od lica ogrzewanej powierzchni przekroju oraz określono położenie izotermy 500°C w sytuacji ogniowej R30-R240. Dodatkowo opracowano nomogramy, które mogą być pomocne do projektowania słupów lub belek żelbetowych w warunkach ogniowych z wykorzystaniem metody izotermy 500°C.

EN

In the article, a series of simulations of unsteady heat flow in reinforced concrete elements heated from four sides were conducted. Selected square cross-sections with side lengths ranging from 16 to 40 cm were examined. Heating of the elements was assumed according to the standard fire curve over a period from 0 to 240 minutes. The study investigated the temperature of the cross-section at distances of a = 2, 4, 6, 8 cm from the heated Surface of the cross-section and determined the location of the 500°C isotherm in fire scenarios R30-R240. Additionally, nomograms were developed that may be useful for designing reinforced concrete columns or beams under fire conditions using the 500°C isotherm method.

7

Analysis of the temperature distribution in an insulated reinforced-concrete building envelope using FBG sensors

Satława Anna, Juraszek Janusz

Budownictwo o Zoptymalizowanym Potencjale Energetycznym

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2024

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Vol. 13

210-217

EN

The progressive climate change caused by anthropological factors has led EU member states to set themselves a very ambitious goal of achieving climate neutrality by 2050. Within the Fit for 55 packages and regulations, a CO2 emissions system (EU ETS) has already been in place since 2005, affecting energy-intensive industries, energy producers and airlines. It is planned that from 2027 the ETS2 system will apply, which will cover CO2 emissions from burning fuels in buildings and road transport. The ETS2 means that gas, coal and fuel oil, i.e. fossil fuels used to heat households, will be subject to taxation. The most effective way to reduce the consumption of these fuels is to reduce the energy intensity of buildings. This can be achieved using appropriate thermal insulation of building envelopes/partitions. Knowledge of the temperature distribution inside a partition can significantly improve the process of thermo-modernization in existing buildings. The paper presents the method and results of the measurement of the thermal distribution inside a reinforced-concrete building wall using FBG sensors.

8

Effect of variable thermal conductivity in semiconducting medium underlying an elastic half-space

Ailawalia Praveen, Priyanka

Archives of Thermodynamics

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2024

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Vol. 45, no. 3

159--166

EN

The aim of the present work is to discuss the effect of varying thermal conductivity in a semiconducting medium under photothermal theory. An infinite elastic half-space is overlying the infinite semiconducting medium, and a constant mechanical force is applied along the interface. The normal mode analysis method is applied to find the analytic components of displacement, stress, carrier density and temperature distribution. It was found that all physical quantities are affected by variable thermal conductivity. The novelty of the paper lies in the fact that no such a problem of variable thermal conductivity has been discussed by any researcher so far.

9

Initiation of initial conditions in a model for thermal analysis of road pavement structures

Bilski Marcin, Górnaś Przemysław, Pożarycki Andrzej, Słowik Mieczysław, Mieczkowski Paweł

Roads and Bridges - Drogi i Mosty

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2023

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Vol. 22, no. 3

275--285

EN

The paper presents an investigation of the possibility for initiation of initial conditions in a road pavement model for thermal analysis incorporating non-stationary heat transfer. The procedure requires performance of computations for a sufficiently long initiation period to obtain the initial temperature distribution that may serve as the basis for further heat transfer analyses. The main part of the article is devoted to presentation of a numerical experiment performed for four configurations of parameters in the heat transfer model in a multilayer system, representing road pavement. Each parameter configuration corresponds to a different pavement structure (two models of flexible pavements and two models of pavements with foam concrete base course). Calculations were performed for three different amplitudes of the sinusoidal function describing the change of temperature in time, which was defined as boundary condition in the pavement model. The numerical experiment was supplemented by calculations performed on a single chosen model parameter configuration, but adopting a boundary condition based on values registered by a sensor installed in real pavement. Analysis of the obtained results confirmed that the presented method of non-stationary heat transfer analysis enables initiation of the initial conditions in the heat equation.

PL

W pracy rozpatrzono możliwość inicjacji warunków początkowych w modelu do analizy termicznej nawierzchni drogowej w warunkach niestacjonarnego przepływu ciepła. Procedura wymaga przeprowadzenia obliczeń dla odpowiednio długiego czasu inicjacji do uzyskania początkowego rozkładu temperatury, który jest podstawą dalszych analiz przepływu energii cieplnej. Główną część pracy stanowi prezentacja eksperymentu numerycznego przeprowadzonego dla czterech konfiguracji wartości parametrów modelu przepływu energii cieplnej w ośrodku wielowarstwowym, jakim jest nawierzchnia. Każda konfiguracja parametrów odpowiada innej konstrukcji (dwa modele nawierzchni podatnej i dwa modele z warstwą z pianobetonu). Obliczenia przeprowadzono kolejno dla trzech różnych wartości amplitud sinusoidalnej funkcji zmiany temperatury w czasie, którą zdefiniowano jako warunek brzegowy w modelu nawierzchni. Uzupełnieniem eksperymentu numerycznego były obliczenia przeprowadzone dla jednej wybranej konfiguracji wartości parametrów modelu, w którym warunek brzegowy stanowiły wartości temperatury zarejestrowane czujnikiem wbudowanym w nawierzchnię. Na podstawie analizy uzyskanych wyników potwierdzono, że inicjacja warunków początkowych w równaniu przewodzenia ciepła jest możliwa w oparciu o analizę niestacjonarnego przepływu ciepła przedstawioną metodą.

10

Analiza przypadków przegrzania mieszkań na ostatnich kondygnacjach budynków w technologii tradycyjnej

Pokorska-Silva Iwona, Nowoświat Artur

Materiały Budowlane

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2023

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nr 11

21--27

PL

Przegrzewanie pomieszczeń ostatniej kondygnacji sprawia, że komfort cieplny nie jest zachowany. W krajach takich jak Polska, gdzie nie używa się powszechnie klimatyzacji, problem ten jest szczególnie widoczny. W celu jego dokładnego zbadania wykonano w okresie letnim pomiary temperatury w pomieszczeniach budynków mieszkalnych wybudowanych w technologii tradycyjnej. Badania te potwierdziły problem przegrzewania tych pomieszczeń, dlatego też analizowano rozkład temperatury w miesiącach letnich w pomieszczeniach poddasza i niższych kondygnacji. Przeprowadzono również pomiar temperatury oraz symulacje numeryczne w budynku testowym. Ponadto wykazano wpływ wskaźnika utrzymania ciepła na średnią, maksymalną i minimalną temperaturę w pomieszczeniach. Za pomocą symulacji w ESP-r pokazano wpływ wskaźnika utrzymania ciepła na rozrzut wyników, gdyż okazuje się, że im większa jest jego wartość, tym rozrzut temperatury w ciągu doby jest mniejszy.

EN

It is commonly known that thermal comfort in the rooms on top floors is interrelated with their overheating. In regions (such as Poland) where air conditioning is not widely used, this problem is particularly evident. In order to thoroughly examine it, temperature measurements were made in the summer period. The measurements were made in the living quarters of buildings constructed in a traditional technology. The tests carried out confirmed that the top-floor rooms were subject to overheating. Therefore, the analysis involved also temperature distribution during the summer months both for attic rooms and rooms on lower floors. Temperature measurement and numerical measurement were also carried out in the test building. Moreover, the impact of the heat retention rate on the average, maximum, and minimum room temperatures was determined. First of all, using the simulation in ESP-r, the impact of heat retention rate on the scatter of results was demonstrated, since it turns out that the higher the value of heat retention rate, the smaller the temperature spread during the day.

11

Variable thermal conductivity in micropolar thermoelastic medium without energy dissipation possessing cubic symmetry

Ailawalia Praveen, Priyanka

International Journal of Applied Mechanics and Engineering

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2023

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Vol. 28, no. 1

1--10

EN

This investigation deals with the effect of variable thermal conductivity in a micropolar thermoelastic medium without energy dissipation with cubic symmetry. The normal mode technique is employed for obtaining components of physical quantities such as displacement, stress, temperature distribution and microrotation.

12

One-dimensional thermal shock problem for a semi-infinite hygrothermoelastic rod

Ailawalia Praveen, Kumar Lalit

International Journal of Applied Mechanics and Engineering

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2023

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Vol. 28, no. 3

1--12

EN

The present research article deals with the study of a boundary value problem of a one-dimensional semi-infinite hygro-thermoelastic rod of length l. The deformation of the rod is under consideration when the left boundary of the hygro-thermoelastic rod is subjected to a sudden heat source. The solutions of the considered variables are decomposed in terms of normal modes. Analytical expressions of displacement, moisture concentration, temperature field, and stresses are obtained and presented graphically for different periods. By studying the one-dimensional thermal shock problem for a semi-infinite hygrothermoelastic rod, the authors aim to gain insights into the fundamental behavior of materials subjected to rapid temperature changes and moisture effects.

13

Influence of environmental conditions on the temperature distribution in a pipe-embedded wall (with a thermally activated element) - analysis of the measurement results

Małek Maria Teresa, Koczyk Halina

Instal

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2023

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nr 10

9--14

EN

The article presents the influence of environmental conditions on the temperature distribution in a pipe-embedded wall. For this purpose, measurements were taken on a test stand, a concrete wall with thermoplastic pipes (with a thermally activated element) embedded inside it in its symmetry axis. The wall is insulated with polystyrene on both sides. Additionally, as a result of its closure in an insulated casing made of oriented strand board (OSB), 2 air zones were created on both sides of the wall. The concreted loop was connected to a cooling bath thermostat used to set the supply temperature in the pipes. In the case of air, its supply to the air zones was provided by ventilation ducts mounted to the housing. The tests consisted of two stages: stabilization of the temperature on the surface of the partition between the concrete and polystyrene layer and the reaction of the structure to a variable outside temperature when fresh outside air was supplied to one of the air zones. All measurements were performed for the following settings: 16°C, 18°C, 20°C and 22°C. It was noted that in order to achieve an even temperature on the wall surface, 24 hours were required from the moment the cooling bath thermostat was turned on. When outside air is supplied to one of the air zones, this partition is resistant to temperature fluctuations, and only after about 6 hours a temperature change of 0.1°C takes place for sensors located at the extreme measurement points and in the other air zone (without air inflow).

PL

W artykule przedstawiono wpływ warunków otoczenia na rozkład temperatury w ścianie z wbudowanymi przewodami. W tym celu wykonano pomiary na stanowisku badawczym, betonowej ścianie z przewodami tworzywowymi (z elementem aktywowanym termicznie) wbudowanymi wewnątrz niej w jej osi symetrii. Ściana ta została z obu stron zaizolowana styropianem. Dodatkowo w wyniku zamknięcia jej w zaizolowanej obudowie wykonanej z płyt OSB powstały dwie strefy powietrzne z obu stron ściany. Zabetonowana pętla została podłączona do ultratermostatu, służącego do nastawienia temperatury zasilania w przewodach. W przypadku powietrza jego dostarczenie do stref powietrznych zapewniały zamontowane do obudowy przewody wentylacyjne. Badania składały się z dwóch etapów: stabilizacji temperatury na powierzchni przegrody między warstwą betonu a styropianu oraz reakcji konstrukcji na zmienną temperaturę zewnętrzną podczas dostarczania do jednej ze stref powietrznych świeżego powietrza zewnętrznego. Wszystkie pomiary odbywały się dla nastaw: 16°C, 18°C, 20°C i 22°C. Zauważono, że w celu osiągnięcia wyrównanej temperatury na powierzchni ściany potrzeba 24 godzin od momentu włączenia ultratermostatu. W przypadku dostarczania powietrza zewnętrznego do jednej ze stref powietrznych, przegroda ta jest odporna na wahania temperatury i dopiero po około 6 godzinach następuje zmiana temperatury o 0,1°C dla czujników zlokalizowanych w skrajnych punktach pomiarowych oraz w drugiej strefie powietrznej (bez napływu powietrza).

14

A comparative study of one-dimensional models for stratified thermal energy storage

Osiadacz Andrzej J., Kotyński Łukasz, Kwestarz Małgorzata

Gaz, Woda i Technika Sanitarna

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2023

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Nr 9

8--14

EN

In the article, a comparative analysis of one-dimensional dynamic models describing Thermal Energy Storages is carried out. A model based on energy balance was compared with a model of conductivity and convection and with a convection model. For each of them, the effect of time on the temperature distribution in the tank was examined and temperature distributions in the tank obtained for the analysed models were compared. Also, the effect of the number of nodes (discretization intervals) on the shape of the stratification curve was studied and the impact of the flow rate of the supplied hot water on the stratification curve was examined.

PL

W artykule dokonano analizy porównawczej jednowymiarowych dynamicznych modeli opisujących Thermal Energy Storages. Porównywano model oparty na bilansie energii z modelem przewodzenia i konwekcji oraz modelem konwekcyjnym. Dla każdego modelu badano wpływ czasu na rozkład temperatury w zasobniku, porównywano rozkłady temperatury w zasobniku otrzymane dla analizowanych modeli a także badano wpływ liczby węzłów (przedziałów dyskretyzacji) na kształt krzywej stratyfikacji. Badano także wpływ natężenia przepływu dostarczanej wody gorącej na krzywą stratyfikacji.

15

Chosen possibilities of ɛ-fuzzy boundary elements method application in the analysis of conductivity problems with uncertainties

Witek Halina, Witek Bernard

Computer Assisted Methods in Engineering and Science

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2023

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Vol. 30, no. 4

407--426

EN

The paper presents a methodology of solving boundary problems with uncertainty parameters based on the use of interval perturbation numbers. This methodology allows for the analysis of very complex problems with different uncertain parameters. Fuzzy Boundary Element Method (FBEM) using ɛ-number will be called ɛ-Fuzzy Boundary Element Method (ɛ-FBEM). Detailed discussion of the problems of computing and applications will be presented on the example of the fuzzy boundary integral equation arising from the boundary problem for the potential problems with heterogeneous, fuzzy boundary conditions of Dirichlet and Neumann type, fuzzy internal sources, fuzzy boundary and fuzzy fundamental solution. The presented methodology can be used to solve various engineering problems (e.g. in civil engineering, power engineering and others) – e.g. to analyze the temperature distribution in structural elements or elements located in the vicinity of objects or devices. In the latter case the increased temperature may be a symptom of a severe failure (e.g. power transformer overload, overexcitation or a fault) which cannot be tolerated due to the threat to the object and to the entire power system. Proposed method maybe used for electrical equipment diagnosis and in consequence as a power system failure prevention. In this paper calculation methodology is illustrated on the example of an area bounded by a square, on the left boundary of which a certain temperature is set, while on the rest of the boundaries the conditions are equal to zero. A dedicated computer program allows for the calculation of both temperature and temperature derivative for any number of boundary elements using ɛ-FBEM.

16

Numerical analysis of the heating of a die for the extrusion of aluminium alloy profiles in terms of thermochemical treatment

Joachimiak Damian, Judt Wojciech, Joachimiak Magda

Archives of Thermodynamics

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2023

|

Vol. 44, no. 2

159--175

EN

Thermochemical treatment processes are used to produce a surface layer of the workpiece with improved mechanical properties. One of the important parameters during the gas nitriding processes is the temperature of the surface. In thermochemical treatment processes, there is a problem in precisely determining the surface temperature of heat-treated massive components with complex geometries. This paper presents a simulation of the heating process of a die used to extrude aluminium profiles. The maximum temperature differences calculated in the die volume, on the surface and at the most mechanically stressed edge during the extrusion of the aluminum profiles were analysed. The heating of the die was simulated using commercial transient thermal analysis software. The numerical calculations of the die assumed a boundary condition in the form of the heat transfer coefficient obtained from experimental studies in a thermochemical treatment furnace and the solution of the nonstationary and non-linear inverse problem for the heat conduction equation in the cylinder. The die heating analysis was performed for various heating rates and fan settings. Major differences in the surface temperature and in the volume of the heated die were obtained. Possible ways to improve the productivity and control of thermochemical treatment processes were identified. The paper investigates the heating of a die, which is a massive component with complex geometry. This paper indicates a new way to develop methods for the control of thermochemical processing of massive components with complex geometries.

17

Detekcja defektów cieplnych systemu ETICS w warunkach quasi-stacjonarnych

Krause Paweł

Materiały Budowlane

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2022

|

nr 6

31--33

PL

W artykule przedstawiono wstępne wyniki badań rozkładu temperatury na powierzchni ściany zewnętrznej z imperfekcjami systemu ETICS, prowadzonych w quasi-stacjonarnych warunkach pomiarowych. Badania wykazały zmianę rozkładu temperatury w obrębie defektów cieplnych o zróżnicowanych szerokościach oraz nieznaczny wpływ występującej dyslokacji cieplnej. Uzyskane wyniki wskazują na konieczność prowadzenia dalszych pomiarów w warunkach rzeczywistych.

EN

The article presents preliminary results of tests of temperature distribution on the surface of an external wall with imperfections of the ETICS system, carried out in quasi-stationary measurement conditions. The research showed a change in the temperature distribution within thermal defects of different widths and a slight influence of the occurring thermal dislocation. The obtained results indicate the necessity to conduct further measurements in real conditions.

18

Impact of thermal renovation on selected characteristics of partition walls and the consumption of heat energy

Cieśliński Krzysztof, Malaga-Toboła Urszula

Technical Transactions

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2021

|

Vol. 118, iss. 1

art. no. e2021018

EN

Renovation of multi-family residentials, including mainly thermal renovation, which includes adding thermal insulation, contributes to the improvement of living conditions. Above all, it reduces the operating costs of renovated buildings by reducing the consumption of heat energy for central heating. This article discusses the impact of light wet thermal renovation on the temperature distribution in the vertical cross-section of the partition wall and the calculation value of the temperature on the inner surface of the partition wall, as well as on the reduction of thermal energy consumption in buildings. The subject of the research was residentials erected in the large-panel, large-block, and traditional technology between 1984 and 1994, managed by Łomża Housing Cooperative (ŁSM).

19

Badania systemu ETICS z polistyrenem EPS i wełną mineralną

Krause Paweł

Przegląd Budowlany

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2021

|

R. 92, nr 11-12

90--93

PL

W celu określenia wpływu wzajemnego połączenia zróżnicowanych izolacji cieplnych w systmie ETICS na stan ochrony cieplno-wilgotnościowej zrealizowano badania w skali laboratoryjnej.

EN

In order to determine the influence of the mutual connection of different thermal insulations in the ETICS system on the condition of thermal and humidity protection, laboratory scale tests were carried out.

20

Formula for temperature distribution in multi-layer optical fibres for high-power fibre lasers

Grábner Martin, Peterka Pavel, Honzátko Pavel

Opto-Electronics Review

|

2021

|

Vol. 29, No. 4

126--132

EN

High power fibre lasers need to be cooled efficiently to avoid their thermal damage. Temperature distribution in fibre should be estimated during the fibre laser design process. The steady-state heat equation in a cylindrical geometry is solved to derive a practical formula for temperature radial distribution in multi-layered optical fibres with arbitrary number of the layers. The heat source is located in one or more cylindrical domains. The validity of the analytical formula is tested by comparison with static heat transfer simulations of typical application examples including octagonal double clad fibre, air-clad fibre, fibre with nonuniform, microstructured core. The accuracy sufficient for practical use is reported even for cases with not exactly cylindrical domains.