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Tytuł:
Electro-thermal Co-simulation of Ics with runtime back-annotation capability
Autorzy:
Timár, A.
Bognár, G.
Poppe, A.
Rencz, M.
Powiązania:
https://bibliotekanauki.pl/articles/397825.pdf
Data publikacji:
2010
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
elektrotermiczna symulacja
rozkład temperatury
logi-termiczna symulacja
logi-thermal simulation
electro-thermal simulation
temperature distribution
Opis:
A novel approach to logical and thermal co-simulation of ASIC circuits is presented in this paper. Numerous electro-thermal simulator implementations are present nowadays, but these simulators approach the electro-thermal simulation domain by co-simulating electronic and thermal effects at a low structural level.This approach has the advantage of being very accurate but at the expense of simulation time. In this paper an alternative way to simulate standard cell ASIC circuits electrically and thermally in a concurrent process, in RTL level is presented. Our approach considers standard cells of a digital design as basic building blocks and calculates a thermal distribution map on the surface of the chip. The temperature map is calculated from the cells' power characteristics and the switching activity of the regularly working circuit. We call the presented approach logi-thermal simulation. An implementation of the method is also presented in this paper: a new simulation software, CettTherm is under heavy development in the Department of Electron Devices at BME, Hungary.
Źródło:
International Journal of Microelectronics and Computer Science; 2010, 1, 3; 287-292
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal bridge effect of air gaps in wall construction
Autorzy:
Kosiński, P.
Powiązania:
https://bibliotekanauki.pl/articles/297806.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie
Tematy:
air thermal bridge
loose mineral wool
air infiltration
thermal simulation
Opis:
The paper presents the phenomenon of thermal bridges caused by air infiltration. The problem of poor air tightness is very common in the former Eastern Bloc countries. The laboratory investigation was set up to recognize the impact of air infiltration on heat flux through the building envelope. The frame wall model insulated with loose mineral wool was investigated in non-isothermal climatic chamber. As a result of cold air infiltration, surfaces of gaps and areas adjacent to them were cooled, which is illustrated on temperature profiles. The forty minutes infiltration of 0o C air resulted as a 3.5o C cooling of gap area. The thermal simulation in Delphin confirmed the laboratory results.
Źródło:
Technical Sciences / University of Warmia and Mazury in Olsztyn; 2015, 18(3); 159-169
1505-4675
2083-4527
Pojawia się w:
Technical Sciences / University of Warmia and Mazury in Olsztyn
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison between thermal simulation results generated by PLECS software and laboratory measurements
Autorzy:
Mysiński, Wojciech
Sysło, Bartłomiej
Powiązania:
https://bibliotekanauki.pl/articles/377458.pdf
Data publikacji:
2019
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
thermal simulation
PLECS
buck converter
thermal time constant
IGBT
diode
power losses
Opis:
This article deals with the subject of simulation of power losses and thermal processes occurring in semiconductors, as illustrated by an example of a DC/DC buck converter. The simulations were performed in PLECS software. The results obtained from the program were compared with measurement results of a laboratory converter model. The physical model is based on the same components as assumed in the simulation. Similarly, the parameters of the transistor control signal were the same. During operation of the converter, the temperature changes were analyzed using a K-type thermocouple. Based on the obtained results of the temperature measurement in the steady state of the converter operation, the correctness of the simulation carried out in the PLECS program was verified and confirmed.
Źródło:
Poznan University of Technology Academic Journals. Electrical Engineering; 2019, 99; 29-40
1897-0737
Pojawia się w:
Poznan University of Technology Academic Journals. Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat transfer simulations in the frequency domain with the application of thermal influence coefficients method
Autorzy:
Gnidzińska, K.
Jabłoński, G.
Napieralski, A.
De Mey, G
Powiązania:
https://bibliotekanauki.pl/articles/397746.pdf
Data publikacji:
2013
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
thermal modelling
thermal simulation
AC
alternating current
modelowanie cieplne
symulacja termiczna
prąd przemienny
Opis:
In this paper an extension of thermal influence coefficients method to frequency domain has been presented. The method allowed the steady-state analysis of three-dimensional heat flow in multilayered structures. The presented modelling is based on Fourier and Hankel transforms, two-port network theory and correction coefficients for close-area distances, allowing emulation of finite heat sources by infinitesimal ones.
Źródło:
International Journal of Microelectronics and Computer Science; 2013, 4, 4; 164-169
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal modelling of modern processors using FEM and compact model
Autorzy:
Galicia, M.
Zając, P.
Maj, C.
Szermer, M.
Napieralski, A.
Powiązania:
https://bibliotekanauki.pl/articles/397698.pdf
Data publikacji:
2015
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
thermal simulation
finite-element method
multi-core
thermal modelling
symulacje termiczne
metoda elementów skończonych
wielordzeniowość
modelowanie cieplne
Opis:
A variety of thermal models has been proposed to predict the temperatures inside modern processors. In this paper, we describe and compare two such approaches, a detailed FEMbased simulation and a simpler architectural compact model. It is shown that both models provide comparable results when it comes to predicting the maximal temperature, however there are also non-negligible differences when estimating thermal gradients within a chip. Furthermore, transient simulation results show some differences in temperature profile during processor heating.
Źródło:
International Journal of Microelectronics and Computer Science; 2015, 6, 3; 110-116
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Investigation of the Air Gap Distribution of Jackets with Different Fits and its Influence on Human Temperature
Autorzy:
Awais, Muhammad
Krzywinski, Sybille
Kyosev, Yordan
Powiązania:
https://bibliotekanauki.pl/articles/2056297.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
thermal simulation
3D fit simulation of clothing
3D scanning
air gap
clothing fit
thermo-physiological model
Opis:
The air gaps underneath clothing have a great influence on the thermal regulation of the human body. The distribution of the air gaps depends on the shape of the human body as well as on clothing style, fit, and deformation properties. This paper reports on the influence of clothing fit on thermophysiological parameters of the human body through thermal simulation. Four different fits of jacket and a test person were considered for the investigation and for simulation purposes. The results of the simulation concluded that different thermal regulations of the human body were exhibited for different fits of the jacket, which is due to distinct air gaps between the human body and clothing for each fit of the jacket. This research work presents a fast method to predict the influence of clothing fit on thermal comfort, which is usually studied by a time-consuming, laborious method – the wear trial.
Źródło:
Fibres & Textiles in Eastern Europe; 2021, 6 (150); 77--86
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation-based investigation for heat transfer behavior of steel reinforcements in concrete machine frames and their thermal effects
Autorzy:
Glänzel, Janine
Geist, Alexander
Ihlenfeldt, Steffen
Powiązania:
https://bibliotekanauki.pl/articles/99966.pdf
Data publikacji:
2019
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
finite element method
reinforced concrete
thermal solid simulation
temperature field
Opis:
The determination of the thermal-elastic behavior is one of the main aspects in the design phase of new machine frames. Prototypically simulation models are used for preliminary investigations, which are based on finite element approaches and usually work with simplified material laws. By the manufacturing of machine frames of concrete steel reinforcements are used to ensure the operation reliability due to the high sensitivity of concrete to tensile stresses. Because of different thermal conductivity and specific heat capacity of steel and concrete the reinforcement has a not negligible influence on the total thermal behavior of the system, which cannot be covered with conventional material laws, e.g. from material libraries. Preliminary investigations show, that a volume fraction more than 1 % of the reinforcement of the total volume can cause a relative error up to ten percent in the temperature field. To reflect the real behavior of reinforced concrete for a machine bed, the influence should be exanimated for two different approaches. Next to the real illustration of the geometry of the reinforcement in the FE-model, decoupled simulation approaches are used on reduced models, which should approach numerically the material behavior of the reinforcement.
Źródło:
Journal of Machine Engineering; 2019, 19, 3; 17-30
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
PV installations and the safety of residential buildings
Autorzy:
Litzbarski, Leszek S.
Seklecki, Konrad
Adamowicz, Marek
Grochowski, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/27323685.pdf
Data publikacji:
2023
Wydawca:
Centrum Rzeczoznawstwa Budowlanego Sp. z o.o.
Tematy:
safety of construction
mechanical load calculation
thermal impact simulation
PV installation
photovoltaic
PV
fotowoltaika
Instalacje fotowoltaiczne
bezpieczeństwo konstrukcji
symulacja wpływu termicznego
obliczanie obciążenia mechanicznego
Opis:
The dynamic development of the photovoltaic industry entails threats that have a direct impact on the safety of residential buildings. Appropriate design of a PV installation can be a challenge due to the multifaceted nature of this issue. The designer should take into account issues related to the selection of electrical parameters of the installation, adapting lightning and surge protection in accordance with applicable standards, ensure the optimization of the system in terms of efficiency and fire safety and calculate the mechanical stress on the rooftop. Unfortunately, most PV installations in Poland are built without any engineering project, which is allowed by the current law. In this article, we describe the results of simulations of real mechanical loads inflicted from the installation of PV panels on flat roofs for various regions of Poland. We also present the results of the simulation of the thermal impact of hot-spots on the roof surface, which can be a potential source of fire. In addition, we propose changes to the regulations that may increase the safety of PV installations mounted on the roofs of residential buildings.
Źródło:
Inżynieria Bezpieczeństwa Obiektów Antropogenicznych; 2023, 4; 1--10
2450-1859
2450-8721
Pojawia się w:
Inżynieria Bezpieczeństwa Obiektów Antropogenicznych
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal evolution of solid targets irradiated by pulsed plasma beams
Autorzy:
Szymczyk, W.
Piekoszewski, J.
Werner, Z.
Szyszko, W.
Powiązania:
https://bibliotekanauki.pl/articles/147099.pdf
Data publikacji:
2002
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
computer simulation
heat flow
thermal evolution
Opis:
Thermal evolution of various targets irradiated with high intensity pulsed ion or plasma beams was determined by computer simulation i.e. by solving numerically one dimensional heat flow equation. The calculations were carried out using the adopted ETLIT computer code (Energy Transport in Laser Irradiated Targets) based on Finite Element Method. The surface temperature, melt depth and liquid duration were computed as a function of pulse energy density, pulse duration, melting temperature and thermal diffusivity of a given material. In particular, some examples are shown for such materials as: Cu, Al, Zn, Fe, Ti, Mo, W, and Al2O3. Various practical aspects of the obtained results are discussed, with a special attention given to less or no intuitively predictable dependencies.
Źródło:
Nukleonika; 2002, 47, 4; 163-166
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Perormance evaluation of liquid-cooled photovoltaic system using numerical method
Autorzy:
Khanjari, Y.
Kasaeian, A.
Pourfayaz, F.
Alayi, R.
Powiązania:
https://bibliotekanauki.pl/articles/957951.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
photovoltaic thermal
water-cooled
simulation
performance
Opis:
The purpose of present study is establishing a simulation model to consider the performance of a water photovoltaic thermal system (PV/T) via the computational fluid dynamics method (CFD). The proposed model includes a water riser tube and an absorber plate to consider the conduction and convection heat transfer mechanisms. The simulation procee was carried out in the ANSYS FLUENT software. The effects of two different parameters on the efficiency and performance of the system were investigated numercically. The performance of the PV/T system versus the changes on the absorbed radiation on the plate and the inlet fluid temperature were analyzed. The temperature distribiution of different sections of the system was obtained. For validation of the presented method, a comparison study was carried out with the experimental results in the literature; satisfactory convergences were found between the measured data and the experimental results.
Źródło:
Advances in Science and Technology. Research Journal; 2016, 10, 32; 184-192
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Simulation and Experimental Investigation of the Thermal Characteristics of Refractory Bricks Produced Using Fireclay and Agroforestry Wastes
Autorzy:
Obidiegwu, Eugenia Obiageli
Esezobor, David Ehigie
Mgbemere, Henry Ekene
Odili, Cletus Chiosa
Powiązania:
https://bibliotekanauki.pl/articles/2105205.pdf
Data publikacji:
2022
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
simulation
insulating bricks
microstructure
thermal characteristics
Opis:
Manufacturing and processing industries usually consume large quantities of materials and energy in the course of their operations. The energy supplied for high-temperature processes are used partially for the actual technical process and between 30 to 40% of the energy escapes through the walls of the reactor into the atmosphere, leading to a high degree of thermal inefficiency and fuel consumption. This paper studies the thermal behaviour of insulating refractory bricks produced from a blend of fireclay and agroforestry wastes. The fireclays used were obtained from Ukpor deposit in Anambra State (Latitude 5.95°N, Longitude 6.92°E), Osiele deposit in Abeokuta, Ogun State (Latitude 7.18°N, Longitude 3.45°E) and Kankara Katsina State (Latitude 11.93°N, Longitude 7.41°E), all of which are in Nigeria. Samples were prepared with various weight percentages (60–100 wt.%) clays and (0–40 wt.%) of agroforestry waste, with grain sizes between 212 and 600 µm. Raw materials and the developed refractory bricks were characterised using appropriate standard techniques. The chemical, mineralogical constituents and phases present in the microstructure were examined. Physical and thermo-mechanical properties were investigated. The insulating refractory bricks developed have porosity of 78.83% , cold crushing strength (CCS) 3.144 kN/m2 and thermal conductivity 0.04–0.046 W/(m∙K) that compare favourably with imported bricks 75–85%, 2.756 kN/m2 and 0.049 W/(m∙K) in both physical, mechanical and thermal properties respectively. The reason is that the agroforestry waste used (coconut shell), served to create the pores that improve insulation after burning. Also the ash that remains serves as reinforcement to improve the mechanical properties. The thermal behaviour of the bricks was studied using Finite Element Method and shows a strong correlation with the experimental findings. This indicates that the produced insulating bricks have the thermal properties required for insulation of furnaces.
Źródło:
Journal of Casting & Materials Engineering; 2022, 6, 2; 45--57
2543-9901
Pojawia się w:
Journal of Casting & Materials Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Intelligent hybrid material slide component for machine tools
Autorzy:
Möhring, H. C.
Wiederkehr, P.
Baumann, J.
König, A.
Spieker, C.
Müller, M.
Powiązania:
https://bibliotekanauki.pl/articles/100179.pdf
Data publikacji:
2017
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
process stability simulation
thermal analysis
machine tool
Opis:
In mid-scale and large five axis overhead gantry type milling machines, the vertical z-slide (ram) often constitutes one of the most sensitive and critical components regarding stiffness, structural vibrations and thermal influences. During machining, the z-slide is loaded by (quasi-) static process and drive forces, transient acceleration forces, periodic excitations by the tool engagement, as well as by thermal effects resulting from altering ambient conditions, heated chips, cooling lubricant and power losses in drives, guides and bearings. Deflections, thermal deformations and vibrations of the z-slide lead to geometric machining errors and inacceptable surface location errors at the workpieces. Furthermore, instable cutting conditions and regenerative chatter limit applicable material removal rates and, thus, productivity. In this work, a newly developed hybrid material structure for an exemplary z-slide, involving metal parts and mineral cast, is introduced. Structural optimization methods as well as process simulation techniques were applied in order to derive the final design solution. The integration of active cooling circuits for thermal stabilization is investigated and the use of fibre optical strain sensors is analysed with respect to a state monitoring of the machine tool component.
Źródło:
Journal of Machine Engineering; 2017, 17, 1; 17-30
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of break shoes wearing in drum break - numerical approach
Autorzy:
Damaziak, K.
Jachimowicz, J.
Małachowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/246894.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
road transport
simulation
brakes
thermal dynamic computations
Opis:
Braking system is one of the key components influencing passenger safety. Today, a design process of brakes is usually experience - driven, based on brake manufactures know - how. Using this approach, it is fairly difficult predict the brake components exact working condition or durability - parameters still more often required in a modern design process, what results in a rising demand for an exact simulation of a braking process. This paper presents numerical analyses of a drum brake. Both static and dynamic FE analyses were conducted in order to verify behaviour of numerical procedures affecting the braking process. The phenomena of heat generation by friction forces and the influence of a wear pattern was emphasized during dynamic calculations, while static analyses were focused on sensitivity to thermal properties of materials. FE models, including loads and boundary conditions, are described in details. Some of the data used during the simulation were taken from experiments. These laboratory tests are also briefly described in the paper. Based on the obtained results, it is shown that a numerical procedure converting sliding energy coming from friction to heat used in a coupled mechanical - thermal dynamic calculation works properly, but is very sensitive to material thermal properties. Proper FE modelling of the contact area and contact forces is also crucial. Unfortunately, due to lack of real material data, the presented results have quantitive character only.
Źródło:
Journal of KONES; 2010, 17, 2; 81-87
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parallel computing in automation of decoupled fluid-thermostructural simulation approach
Autorzy:
Glänzel, Janine
Naumann, Andreas
Kumar, Tharun Suresh
Powiązania:
https://bibliotekanauki.pl/articles/100135.pdf
Data publikacji:
2020
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
thermal effects
simulation
machine tool
environment
positioning error
Opis:
Decoupling approach presents a novel solution/alternative to the highly time-consuming fluid-thermal-structural simulation procedures when thermal effects and resultant displacements on machine tools are analyzed. Using high dimensional Characteristic Diagrams (CDs) along with a Clustering Algorithm that immensely reduces the data needed for training, a limited number of CFD simulations can suffice in effectively decoupling fluid and thermal-structural simulations. This approach becomes highly significant when complex geometries or dynamic components are considered. However, there is still scope for improvement in the reduction of time needed to train CDs. Parallel computation can be effectively utilized in decoupling approach in simultaneous execution of (i) CFD simulations and data export, and (ii) Clustering technique involving Genetic Algorithm and Radial Basis Function interpolation, which clusters and optimizes the training data for CDs. Parallelization reduces the entire computation duration from several days to a few hours and thereby, improving the efficiency and ease-of-use of decoupling simulation approach.
Źródło:
Journal of Machine Engineering; 2020, 20, 2; 39-52
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parameterization of environmental influences by automated characteristic diagrams for the decoupled fluid and structural-mechanical simulations
Autorzy:
Glänzel, Janine
Kumar, Tharun Suresh
Naumann, Christian
Putz, Matthias
Powiązania:
https://bibliotekanauki.pl/articles/99399.pdf
Data publikacji:
2019
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
thermal effects
simulation
machine tool
environment
positioning error
Opis:
Thermo-elastic effects contribute the most to positioning errors in machine tools especially in operations where high precision machining is involved. When a machine tool is subjected to changes in environmental influences such as ambient air temperature, velocity or direction, then flow (CFD) simulations are necessary to effectively quantify the thermal behaviour between the machine tool surface and the surrounding air (fluid). Heat transfer coefficient (HTC) values effectively represent this solid-fluid heat transfer and it serves as the boundary data for thermo-elastic simulations. Thereby, deformation results can be obtained. This two-step simulation procedure involving fluid and thermo-structural simulations is highly complex and time-consuming. A suitable alternative for the above process can be obtained by introducing a clustering algorithm (CA) and characteristic diagrams (CDs) in the workflow. CDs are continuous maps of a set of input variables onto a single output variable, which are trained using data from a limited number of CFD simulations which is optimized using the clustering technique involving genetic algorithm (GA) and radial basis function (RBF) interpolation. The parameterized environmental influences are mapped directly onto corresponding HTC values in each CD. Thus, CDs serve as look-up tables which provide boundary data (HTC values along with nodal information) under several load cases (combinations of environmental influences) for thermo-elastic simulations. Ultimately, a decoupled fluid-structural simulation system is obtained where boundary (convection) data for thermo-mechanical simulations can be directly obtained from CDs and would no longer require fluid simulations to be carried out again. Thus, a novel approach for the correction of thermo-elastic deformations on a machine tool is obtained.
Źródło:
Journal of Machine Engineering; 2019, 19, 1; 98-113
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and verification of the chip thermal model: the assessment of a power modules resistance to high current peaks
Autorzy:
Pavlásek, P.
Mrázik, M.
Pavelek, M.
Dobrucký, B.
Powiązania:
https://bibliotekanauki.pl/articles/377849.pdf
Data publikacji:
2018
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
power modules
thermal model
simulation
finite element method
Opis:
The paper is focused on creating a thermal model which provides information about the thermal conditions in the semiconductor devices. Increasing the current density and pressure on prices make the optimization of thermal systems an important part in the design process. Simulation analysis has become with development of computer technology an excellent equipment to achieve it. In creating the model, we take account of material and geometric parameters of bonded chips. By the simulation we obtain the necessary information about the components and thermal stresses, these results can be applied in the device design procedure and technology of production. Resistance to bonded diodes is determined by chip parameters and bonding parameters such as the number of bundles, their spacing, and material. Resistance in practice is determined by experimentally measuring IFSM, a peak permeable, unrepeatable current. Also, in the work we analysed voltage-current VA characteristics of power diodes such as threshold voltage, also the closing voltage we tested functionality and we observe changes in the behaviour of the component and, last but not least, the characteristics of thermal resistance and thermal impedance that served as elements for the construction of an equivalent model. In the next part of the paper, in the context of the works, the methods of bindings of PCB components are currently being extended and used in current technological processes and we also concentrate on the dimensional parameters of the modules used to create an equivalent electrical circuit. The presented assembled simplified model respects the chip size, number of bonding wires, and their layout on the chip. For the concept of nine bonds, we had two types of placement from a variety of bonds, so we also respected this factor in the design of the model. As an example, there is a diode module investigated (SKEE SEMIPACK® 2, 1600V/174A).
Źródło:
Poznan University of Technology Academic Journals. Electrical Engineering; 2018, 95; 57-65
1897-0737
Pojawia się w:
Poznan University of Technology Academic Journals. Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Problems of the starting and operating of hydraulic components and systems in low ambient temperature (Part V) methods ensuring correct start-up of hydraulic components of ship’s onboard devices in low ambient temperatures
Autorzy:
Jasiński, R.
Powiązania:
https://bibliotekanauki.pl/articles/259768.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
hydraulic drive
hydraulic components
thermal shock
computer simulation
Opis:
A large number of hydraulic devices and systems are started in low ambient temperatures. A good example of such a device is the hoisting winch on the ship. Starting hydraulic drive units in thermal shock conditions (rapid supply of hot oil to the cold unit) may lead to incorrect operation of the actuating system, for instance, due to the loss of clearance between cooperating elements. The article presents methods to prevent the disappearance of effective clearance in a hydraulic motor started in thermal shock conditions. For this reason, the structure of the hydraulic satellite motor was complemented by elements creating special channels through which hot oil could flow and additionally heat fixed parts of the motor. This solution ensures faster heating of motor housing, thus decreasing the temperature difference between the housing and the satellites during motor start-up in thermal shock conditions.
Źródło:
Polish Maritime Research; 2017, 4; 47-56
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Problems of the starting and operating of hydraulic components and systems in low ambient temperature (Part IV) Modelling the heating process and determining the serviceability of hydraulic components during the starting-up in low ambient temperature
Autorzy:
Jasiński, R.
Powiązania:
https://bibliotekanauki.pl/articles/260163.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
hydraulic drive
hydraulic components
thermal shock
computer simulation
Opis:
Designers of hydraulically driven machines and devices are obliged to ensure during design process their high service life with taking into account their operational conditions. Some of the machines may be started in low ambient temperature and even in thermal shock conditions (due to delivering hot working medium to cold components). In order to put such devices into operation appropriate investigations, including experimental ones - usually very expensive and time-consuming, are carried out. For this reason numerical calculations can be used to determine serviceability of a hydraulic component or system operating in thermal shock conditions. Application of numerical calculation methods is much less expensive in comparison to experimental ones. This paper presents a numerical calculation method which makes it possible to solve issues of heat exchange in elements of investigated hydraulic components by using finite elements method. For performing the simulations the following data are necessary: ambient temperature, oil temperature, heat transfer coefficient between oil and surfaces of elements, as well as areas of surfaces being in contact with oil. By means of computer simulation method values of clearance between cooperating elements as well as ranges of parameters of correct and incorrect operation of hydraulic components have been determined. In this paper results of computer simulation of some experimentally tested hydraulic components such as axial piston pump and proportional spool valve, are presented. The computer simulation results were compared with the experimental ones and high conformity was obtained.
Źródło:
Polish Maritime Research; 2017, 3; 45-57
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efficient quantification of free and forced convection via the decoupling of thermo-mechanical and thermo-fluidic simulations of machine tools
Autorzy:
Glaenzel, J.
Ihlenfeldt, S.
Naumann, C.
Putz, M.
Powiązania:
https://bibliotekanauki.pl/articles/100153.pdf
Data publikacji:
2018
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
thermal effects
simulation
machine tool
environment
positioning error
Opis:
Thermo-elastic deformations represent one of the main reasons for positioning errors in machine tools. Investigations of the thermo-mechanical behaviour of machine tools, especially during the design phase, rely mainly on thermo-elastic simulations. These require the knowledge of heat sources and sinks and assumptions on the heat dissipation via convection, conduction and radiation. Forced convection such as that caused by moving assemblies has both a large influence on the heat dissipation to the surrounding air. The most accurate way of taking convection into account is via computational fluid dynamics (CFD) simulations. These simulations compute heat transfer coefficients for every finite element on the machine tool surface, which can then be used as boundary conditions for accurate thermo-mechanical simulations. Transient thermo-mechanical simulations with moving assemblies thus require a CFD simulation during each time step, which is very time-consuming. This paper presents an alternative by using characteristic diagrams to interpolate the CFD simulations. The new method uses precomputed thermal coefficients of a small number of load cases as support points to estimate the convection of all relevant load cases (i.e. ambient conditions). It will be explained and demonstrated on a machine tool column.
Źródło:
Journal of Machine Engineering; 2018, 18, 2; 41-53
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Working temperature calculation of single-core cable by nonlinear finite element method
Autorzy:
Meng, Xiaokai
Han, Peijie
Liu, Yongxin
Lu, Zhumao
Jin, Tao
Powiązania:
https://bibliotekanauki.pl/articles/141018.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cable
finite element simulation model
thermal conductivity
operating temperature
Opis:
By simulating the actual working conditions of a cable, the temperature variation rule of different measuring points under different load currents was analyzed. On this basis, a three-dimensional finite element model (FEM) was established, and the difference and influence factors between the simulation temperature and the experimental measured value were discussed, then the influence of thermal conductivity on the operating temperature of the conductor layer was studied. Finally, combined with the steady-state thermal conductivity model and the experimental measured data, the relation between thermal conductivity and load current was obtained.
Źródło:
Archives of Electrical Engineering; 2019, 68, 3; 643-656
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The analysis of thermal comfort in the school and the wedding house
Analiza komfortu cieplnego w szkole i domu weselnym
Autorzy:
Zender-Świercz, E.
Jędrzejczyk, O.
Kaczorowska, K.
Powiązania:
https://bibliotekanauki.pl/articles/402185.pdf
Data publikacji:
2018
Wydawca:
Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw
Tematy:
thermal comfort
air conditioning
simulation
komfort termiczny
klimatyzacja
symulacje
Opis:
The environment, where people are staying, should provide thermal comfort. It means that the equilibrium of the amount of heat produced in the human body and the amount of heat lost to the environment should be kept. To achieve the suitable conditions of air there the air conditioning, ventilation and heating systems are used. These systems regulate the air parameters and maintain them at the desired level. Designers locate, most commonly, the supply units of air conditioning systems in the ceiling in the central part of the room or near the windows without taking into account the specificity of the premises. However, such an approach may contribute to the lack of thermal comfort. The sensation of air is a very subjective indicator that depends on many variables. The authors of the article made an attempt to analyze the influence of the type of air conditioning system and location of air supply units on the thermal comfort in rooms of different use.
Środowisko, w którym przebywa człowiek powinno zapewniać odczuwanie komfortu. tzn. powinna być zachowana równowaga pomiędzy ilością ciepła wytwarzanego w ciele człowieka a ilością ciepła traconego do otoczenia. Aby uzyskać taki stan powietrza w pomieszczeniach, stosuje się różne systemy wentylacji, klimatyzacji i ogrzewania. Układy te regulują parametry powietrza i utrzymują je na żądanym poziomie. Projektanci lokalizują elementy nawiewne instalacji klimatyzacji najczęściej w suficie w centralnej części pomieszczenia lub przy oknach bez uwzględniania specyfiki pomieszczenia. Jednak takie spojrzenie na instalację może przyczynić się do braku warunków komfortu cieplnego. Postrzeganie stanu powietrza jest bardzo subiektywnym wskaźnikiem zależnym od wielu zmiennych. W artykule podjęto próbę analizy wpływu rodzaju instalacji klimatyzacji oraz rozmieszczenia elementów nawiewnych w pomieszczeniach o różnym przeznaczeniu.
Źródło:
Structure and Environment; 2018, 10, 1; 75-81
2081-1500
Pojawia się w:
Structure and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the cook-off processes of HMX-based mixed explosives
Autorzy:
Chen, L.
Ma, X.
Lu, F.
Wu, J.
Powiązania:
https://bibliotekanauki.pl/articles/358000.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
explosives
chemical kinetics
thermal decomposition
cook-off
numerical simulation
Opis:
In order to investigate the characteristics of the thermal reaction for two kinds of mixed explosives, PBXC-10 (HMX/TATB/Binder, 38/57/5) and JO-8 (HMX/Binder, 95/5), multi-point measured temperature cook-off tests were carried out at different heating rates. The thermal transfer and finite chemical reactions that include the β→δ transition of HMX, and the endothermic and exothermic cook-off processes were analyzed. A 3D model of the explosive cook-off test was developed to simulate the thermal and chemical behaviour in a thermal ignition. The decomposition mechanisms for HMX and TATB are described by the multistep, chemical kinetic model. The thermal properties, decomposition pathways, and chemical kinetic reaction rate constants for each component are used to develop the reaction courses at various weight percentages. The thermal decomposition reaction of a multi-component, mixed explosive can be predicted as long as the chemical kinetics model of each single-base explosive and binder are known. The phase transition of HMX has an influence on the temperature of the explosive, especially for an explosive with a high HMX content. For mixed explosives containing HMX and TATB, most of the heat release is produced by the decomposition of HMX before ignition, but TATB can delay the ignition time and decrease the reaction violence in the cook-off process.
Źródło:
Central European Journal of Energetic Materials; 2014, 11, 2; 199-218
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Operating Window in Selective Laser Melting Processes
Autorzy:
Kozak, Jerzy
Zakrzewski, Tomasz
Witt, Marta
Dębowska-Wąsak, Martyna
Powiązania:
https://bibliotekanauki.pl/articles/36833418.pdf
Data publikacji:
2023
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
selective laser melting
SLM
thermal limitation
mathematical modeling
simulation
Opis:
Selective laser melting (SLM) is one of the most effective methods of additive manufacturing (AM). It is used to manufacture products with very complex geometries using a wide range of materials. Practical process conditions are limited by the occurrence of undesirable melting instabilities that degrade the surface quality and lead to product defects. These disadvantages are related to the thermal limitations of the SLM process. The lower thermal limit is due to the need to completely melt the powder layer and partially remelt the underlying layer again to ensure proper bonding between the layers. Exceeding the upper thermal limit in the molten metal pool may cause extensive evaporation, boiling and ejection of molten metal droplets outside the melting area. The article presents an approach and methodology that enable the determination of thermal limits and the operating window of SLM/selective laser sintering (SLS) processes in a relatively simple way. The studies have been performed using various settings of SLM process parameters. The usefulness of the preliminary determination of thermal limitations and approximate prediction of operating window of SLM has been confirmed experimentally and by more accurate computer simulation.
Źródło:
Transactions on Aerospace Research; 2023, 4 (273); 18-32
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of Machine Tool Operational Properties
Autorzy:
Jędrzejewski, J.
Kwaśny, W.
Powiązania:
https://bibliotekanauki.pl/articles/99436.pdf
Data publikacji:
2015
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
machine tool
intelligence
accuracy
holistic modelling
simulation
thermal properties
Opis:
This paper presents the main directions in the development of machine tools and the practical implementations of new technologies by machine tool producers, aimed at meeting the business requirements. The possibilities of applying intelligent functions in high-performance machine tools and the trends in the development of intelligent machine tools are discussed. The vital importance of the holistic modelling and numerical simulation of the operational properties of machine tools at all the stages of their creation and the necessity of integrating the machine tool with the control system and the process during simulation and virtualization are highlighted.
Źródło:
Journal of Machine Engineering; 2015, 15, 1; 5-24
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy consumption, thermal comfort and indoor air quality assessment in a school building using three air-cooling systems
Autorzy:
Romero, María Jesús
Comino, Francisco
Ruiz de Adana, Manuel
Powiązania:
https://bibliotekanauki.pl/chapters/31233748.pdf
Data publikacji:
2021
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
HVAC systems
classroom
thermal comfort
energy consumption
energy simulation
Opis:
Efficient air-cooling systems for hot climatic conditions, such as southern Europe, are required in the context of Nearly Zero Energy Buildings. Regenerative indirect evaporative coolers, RIEC, and desiccant regenerative indirect evaporative coolers, DRIEC, could be considered an innovative alternative to direct expansion conventional systems, DX. The main objective of this work was to evaluate the seasonal performance of three air-cooling systems in terms of thermal comfort, air quality and energy consumption in a standard classroom. Several energy simulations were carried out to evaluate these indexes in the climate zone of Lampedusa, in Mediterranean area, by using European Standards. The simulations were based on experimentally validated models. DRIEC system was the recommended system to serve a standard classroom in terms of thermal comfort and RIEC system in terms of air quality and energy consumption. DX system achieved similar comfort favourable conditions to DRIEC system. However, it always worked in III unfavourable category of air quality and consumed three times more than RIEC and DRIEC systems.
Źródło:
Innovations – Sustainability – Modernity – Openness. Modernity in engineering; 115-121
9788366391901
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-25 z 67

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