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Tytuł:
Analysis of non-equidistant baffle spacing in a small shell and tube heat exchanger
Autorzy:
Aziz, Abdullah
Rehman, Shafique
Powiązania:
https://bibliotekanauki.pl/articles/240423.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
thermal distribution
baffle spacing
heat exchanger
turbulence modeling
CFD study
Opis:
Most of the formulations regarding the characteristics of a shell and tube heat exchanger have a common assumption; namely that the baffle plates are equidistant. This assumption fails to cater the real world scenario for defective baffles as the alteration in a shell and tube heat exchanger invalidates the equidistant baffle spacing of the plates. In this regard, a small six baffles heat exchanger was modeled in the computational fluid dynamics software package and studied by removing each baffle plate one at a time. Effect of removing each baffle plate on the temperature, pressure, heat transfer coefficient, and total heat transfer rate was recorded. It was observed that variation in the pressure drop for the same number of baffle plates varies along the axial order of the plates. The change in pressure drop due to the removal of the baffle plate near the inlet and the outlet was lowest and reaches a maximum in the axial center. It was also found that the plates below the radial center contribute higher towards the overall heat transfer as compared to those above.
Źródło:
Archives of Thermodynamics; 2020, 41, 2; 201-221
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of the Ansys Fluent program for modelling environmental phenomena in a living room
Autorzy:
Kosiń, Mariusz
Powiązania:
https://bibliotekanauki.pl/articles/2174974.pdf
Data publikacji:
2021
Wydawca:
Politechnika Częstochowska
Tematy:
modelowanie numeryczne
CFD
rozkład termiczny
rozkład wilgotności
komfort cieplny
rozkład temperatury
numerical modeling
thermal distribution
humidity distribution
thermal comfort
temperature distribution
Opis:
The article presents a three-dimensional numerical analysis of heat and humidity parameters carried out for a living room in a multi-family building. The aim of the analysis was to compare alternative heating methods with the existing one. Two cases were included in the analysis: case I - the existing state, case II - the existing state with an additional panel heater. In order to verify the numerical analysis for case I, the temperature and relative humidity were measured. During the heating period, the thermal conditions in the room did not favor the comfort of users, especially in one part of the room. The study may be a tool for future research related to the implementation of the climatic conditions of rooms with similar structural and functional features.
Źródło:
Budownictwo o Zoptymalizowanym Potencjale Energetycznym; 2021, 10, 2; 53--59
2299-8535
2544-963X
Pojawia się w:
Budownictwo o Zoptymalizowanym Potencjale Energetycznym
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania nad wykorzystaniem krajowej biomasy w produkcji zasypek odlewniczych
Studies on the use of domestic biomass in production of casting powders
Autorzy:
Pogorzałek, J.
Borecki, M.
Różański, P.
Powiązania:
https://bibliotekanauki.pl/articles/181713.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Metalurgii Żelaza im. Stanisława Staszica
Tematy:
biomasa
zasypki odlewnicze
właściwości fizykochemiczne
rozkład termiczny
biomass
casting powders
physical and chemical characteristics
thermal distribution
Opis:
Przedstawiono przebieg i wyniki prac badawczych mających na celu opracowanie technologii wytwarzania zasypek odlewniczych dla stalownictwa z wykorzystaniem krajowej biomasy. Przeprowadzono badania właściwości fizyko-chemicznych wybranych odpadów z przemysłu rolno-spożywczego celem porównania z właściwościami szeroko stosowanej obecnie łuski ryżowej. Wykonano analizy chemiczne, analizy termiczne TG-DSC w atmosferze obojętnej i utleniającej oraz laboratoryjne badania procesu termicznego rozkładu otrąb, plew i innych odpadów z przetwórstwa krajowych zbóż. Skuteczność opracowanych składów zasypek izolacyjnych i izolacyjno-egzotermicznych z wykorzystaniem w/w biomas oraz odpadów mineralnych w postaci żużli stalowniczych określono w warunkach laboratoryjnych. Stwierdzono możliwość zastąpienia importowanej łuski ryżowej krajowymi odpadami przemysłu zbożowego w zasypkach odlewniczych.
The paper presents the course and results of the research works aimed at developing technology for manufacturing casting powders for steelmaking using the domestic biomass. The tests of physical and chemical characteristics of selected waste from the food processing industry were carried out to compare them to those of the rice husk which is widely used at present. Chemical analyses, TG-DSC thermal analyses in inert gas atmosphere and in oxidizing atmosphere conditions and laboratory tests of thermal decomposition of bran, chaffs and other wastes from domestic cereals treatment processes were done. Insulation efficiency of developed casting powders (insulating and exothermicinsulating types) based on the above-mentioned biomasses and mineral wastes (steelmaking slags) was determined in laboratory scale. It was concluded that domestic biomasses (wastes from the food processing industry) could replace the imported rice husk in casting powders.
Źródło:
Prace Instytutu Metalurgii Żelaza; 2013, T. 65, nr 4, 4; 8-17
0137-9941
Pojawia się w:
Prace Instytutu Metalurgii Żelaza
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The use of thermal mapping in evaluation of mechanically induced electrical degradation of graphene - based transparent heaters
Zastosowanie mapowania termicznego do oceny elektrycznej degradacji uszkodzonych mechanicznie grafenowych przezroczystych elementów grzejnych
Autorzy:
Kozłowska, A.
Gawlik, G.
Piątkowska, A.
Krajewska, A.
Kaszub, W.
Powiązania:
https://bibliotekanauki.pl/articles/192205.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Technologii Materiałów Elektronicznych
Tematy:
graphene
transparent layer
heating element
infrared imaging
thermal distribution
mechanical defect
grafen
warstwa przezroczysta
element grzejny
obrazowanie w podczerwieni
rozkład termiczny
defekt mechaniczny
Opis:
The purpose of this study is to investigate temperature distributions of graphene-based transparent heaters deposited on glass. Furthermore it analyses the influence of layer discontinuities such as scratches and cracks on the performance of Joule-heated samples. Graphene mechanical strength was examined by the nanoscratch method at incremental loads using a ball on a flat sample surface. In the case of the controlled load several scratches were produced on the graphene surface. Tribological tests were conducted at different constant loads. the paper presents scanning electron micrograph (seM) observations of the modified graphene surface. Infrared imaging of Joule-heated samples indicates a significant uniformity deterioration of the thermal maps due to the current flow alteration in the presence of structural imperfections. The results obtained in the course of this study give new insight into the role of defects such as cracks or discontinuities in the overall performance of graphene transparent layers.
W pracy przeprowadzone zostały badania rozkładów termicznych elementów grzejnych zawierających warstwy grafenowe naniesione na szkło. Analizowany był wpływ nieciągłości warstwy w postaci zarysowań i pęknieć. Mechaniczna wytrzymałość grafenu badana była za pomocą metody nano-zarysowań przy narastającym obciążeniu kulki oddziaływującej na płaską powierzchnię próbki. Przy zastosowaniu kontrolowanego maksymalnego obciążenia wykonano szereg rys na powierzchni grafenu. Przeprowadzono testy tribologiczne dla różnych stałych obciążeń. W pracy zawarto wyniki analizy zmodyfikowanej powierzchni grafenu za pomocą skaningowego mikroskopu elektronowego (SEm). Obrazowanie w podczerwieni próbek podgrzewanych za pomocą wydzielanego ciepła Joula wskazały na znaczne pogorszenie jednorodności rozkładów termicznych, na skutek zmiany drogi przepływu prądu w przypadku występowania niedoskonałości strukturalnych. Wyniki pozwalają na ocenę wpływu defektów w postaci pęknięć i nieciągłości na działanie przezroczystych grafenowych warstw grzejnych.
Źródło:
Materiały Elektroniczne; 2017, T. 45, nr 1, 1; 12-17
0209-0058
Pojawia się w:
Materiały Elektroniczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Numerical Modeling of Thermal Stress Distribution in Thermal Barrier Coatings
Autorzy:
Jasik, A.
Powiązania:
https://bibliotekanauki.pl/articles/353586.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
temperature distribution
thermal stress
TBC
FEM
Opis:
The paper presents the results of numerical calculations of temperature and thermal stress distribution in thermal barrier coatings deposited by thermal spraying process on the nickel based superalloy. An assumption was made to apply conventional zirconium oxide modified with yttrium oxide (8YSZ) and apply pyrochlore type material with formula La2Zr2O7. The bond coat was made of NiCoCrAlY. Analysis of the distribution of temperature and stresses in ceramic coatings of different thicknesses was performed in the function of bond-coat thickness and the type of ceramic insulation layer. It was revealed that the thickness of NiCrAlY bond-coat has not significant influence on the stress distribution, but there is relatively strong effect on temperature level. The most important factor influenced on stress distribution in TBC system is related with type and properties of ceramic insulation layer.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 3; 1433-1437
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental testing of the vehicle heating system
Autorzy:
Kucybała, P.
Gawlik, A.
Powiązania:
https://bibliotekanauki.pl/articles/246308.pdf
Data publikacji:
2017
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
heating system
temperature distribution
temperature tests
thermal chamber
Opis:
An important problem in the design of machinery and equipment at the stage of determining their structure is the issue of providing adequate thermal comfort to users while operating in variable climatic and environmental conditions. This issue is of particular importance because all types of machinery and devices are equipped with very expensive and automated control and monitoring system, which should guarantee adequate warming conditions and should work under different climatic conditions. Examples of these tendencies are special solutions for vibroacoustic insulation of the inside of the devices, special air conditioning equipment, special constructions, ergonomic inside solutions. The process of shaping the discussed structural design of vehicles in terms of meeting the relevant technical and operational criteria is currently being increasingly realized through experimental tests of prototypes supported by numerical calculations. The purpose of this paper is to present the methodology of conducting test stand as a stage for the experimental determination and verification of temperature distribution, the location of heating and air conditioning devices in a prototype vehicle in variable climatic conditions (minus 15º C). The research was carried out in a large-scale climate chamber. It covered the process of heating up the passenger area of the bus and the time of temperature stabilization on the inside of the vehicle while operating the heating systems. An additional attempt was made to test the heating system while the vehicle was in motion and to open the vehicle door to simulate the stopping of the vehicle at the bus stop. Another aspect that was analysed was the impact of the installed convector on the vehicle when the liquid heater was off.
Źródło:
Journal of KONES; 2017, 24, 3; 135-141
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of two-stage thermal disintegration on particle size distribution in sewage sludge
Autorzy:
Kaczmarek, A. M.
Gaca, J.
Powiązania:
https://bibliotekanauki.pl/articles/777862.pdf
Data publikacji:
2013
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
laser diffraction
particle size distribution
sludge
thermal hydrolysis
Opis:
The effect of two-stage thermal disintegration of sewage sludge on the particle size distribution using laser diffraction method has been studied. The sludge was sampled from municipal sewage treatment plant after each stage of disintegration. The first stage of disintegration known as homogenization proceeds at temperature of 70-90°C and pressure of 3 bar, the second stage called thermal hydrolysis was performed at temperature of 160-170°C and pressure of 6 bar. It was found that the first stage of disintegration has the strongest impact on the reduction of the sludge particle size and changes in chemical properties. The maximum size of the particles from raw sewage before disintegration was 310 μm. After first stage of the process average size of the particles was 250 μm, and during the second stage it was reduced to 226 μm. Sludge disintegration degree (DDCOD) of 59% confirms high effectiveness of the process. We established that the redox potential (Eh) of sludge effluents was changed after each step of the studied process. Furthermore, chemical oxygen demand (COD) increases which leads to the conclusion that resizing of floccules is accompanied by hydrolysis.
Źródło:
Polish Journal of Chemical Technology; 2013, 15, 3; 69-73
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
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:
Research on heat flow in granite sample using thermal imaging camera
Autorzy:
Małek, E.
Miedzińska, D.
Niezgoda, T.
Stankiewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/242569.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
thermovision
thermal imaging camera
temperature distribution
granite
aluminum foam sample
heat flow
Opis:
Research on heat flow in granite sample and sample of aluminium foam with the use of a thermal imaging camera is presented in the paper. Temperature distribution on the surface of the sample as a function of time was obtained on the basis of data from the thermal imaging camera. Thermovision is one of the most universal technology, which is applied for detection of infrared radiation. This technique allows observing and record infrared radiation emitted by objects located in the surrounding environment. This technology allows obtaining, in a short time, temperature distribution on the surface of the sample. The thermograms (pictures showing on the surface of the object) are types of photos showing temperature distribution on the tested object surface which is achieved on the base of a specified range of electromagnetic radiation. Accurate measurement of the temperature distribution on the heated granite sample surface was obtained using a thermal imaging camera FLIR SC 6000. Thermal imaging camera was connected to the computer equipped with control software FLIR ResearchIR Max. Heat source was applied in the experiment as a cast iron hotplate with high efficiency heating, gradual control and 1500W power. Obtained results showed regular temperature distribution over the surface of researched sample.
Źródło:
Journal of KONES; 2016, 23, 4; 327-333
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of various control techniques for motor-pump sets applied in selected water distribution systems
Autorzy:
Popenda, A.
Powiązania:
https://bibliotekanauki.pl/articles/1372738.pdf
Data publikacji:
2011
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Napędów i Maszyn Elektrycznych Komel
Tematy:
elektrociepłownia
system dystrybucji wody
pompa
thermal-electric power station
water distribution system
pump
Opis:
The water distribution system applied in the thermal-electric power station EC Tychy SA is analyzed. The economical aspects of various control techniques for motor-pump sets in the aforementioned system are presented in the paper on the example of pumps working out of the cold season. The reasons of control losses occurring in the present system are depicted. The way of improvement of control effectiveness is proposed but unprofitability of the investment is also shown. A control of pumps by throttling and control by rotational speed changes are compared in the paper. It is shown that control by rotational speed changes causes similar losses like control by throttling if application of variable-speed technique is not preceded by appropriate adaptation of water distribution system, especially by adjustment of pump rated parameters.
Źródło:
Maszyny Elektryczne: zeszyty problemowe; 2011, 4, 92; 97-101
0239-3646
2084-5618
Pojawia się w:
Maszyny Elektryczne: zeszyty problemowe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Size and Morphology of Yttria Nanopowders Obtained by Solution Combustion Synthesis
Autorzy:
Gizowska, M.
Kobus, I.
Perkowski, K.
Piątek, M.
Konopka, G.
Witosławska, I.
Osuchowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/354879.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
particle size distribution
solution combustion synthesis
thermal analysis
Y2O3 nanopowder
Opis:
The work presents results of solution combustion method utilization for yttria (Y2O3) nanopowder fabrication. Experiments were carried out with four different reducing agents: urea, glycine, citric acid and malonic acid added in stoichiometric ratio. The reactions were investigated using simultaneous DSC/DTA thermal analysis. After synthesis the reaction products were calcined at temperature range of 800-1100°C and analyzed in terms of particle size, specific surface area and morphology. Best results were obtained for nanoyttria powder produced from glycine. After calcination at temperature of 1100°C the powder exhibits in a form of nanometric, globular particles of diameter <100 nm, according to SEM analysis. The dBET for thus obtained powder is 104 nm, however the powder is agglomerated as the particle size measured by dynamic light scattering analysis is 1190 nm (dV50).
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 2; 743-748
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variable thermal conductivity in micropolar thermoelastic medium without energy dissipation possessing cubic symmetry
Autorzy:
Ailawalia, Praveen
Priyanka
Powiązania:
https://bibliotekanauki.pl/articles/27312393.pdf
Data publikacji:
2023
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
transfer ciepła
mikrorotacja
temperatura
variable thermal conductivity
microrotation
temperature distribution
normal mode analysis
Opis:
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.
Źródło:
International Journal of Applied Mechanics and Engineering; 2023, 28, 1; 1--10
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comparative study of differential transformation and homotopy perturbation methods for transient combustion analysis for iron micro-particles in a gaseous oxidizing medium
Autorzy:
Yinusa, A. A.
Sobamowo, M. G.
Powiązania:
https://bibliotekanauki.pl/articles/1046539.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Differential transformation method
Homotopy perturbation method
Iron particle combustion
Temperature distribution
Thermal radiation
Opis:
In this paper, a comparative study of differential transformation and homotopy perturbation methods for transient combustion analysis of iron micro-particles in a gaseous oxidizing medium is presented. Also, parametric studies are carried out to properly understand the reaction of the process and the associated burning time. Thermal radiation effect from the external surface of burning particle and variation of iron particle density with temperature are considered. The solutions obtained by DTM and HPM are compared with those of the fourth order Runge-Kutta numerical method. Results show that DTM has more accurate results between the two approximate analytical methods considered. Also, results show that by increasing the heat realized parameter, combustion temperature increased and it faster reaches to its constant value. It is envisaged that the present study will create tremendous insight into means of properly managing combustible micro particles exiting factories and production process organization.
Źródło:
World Scientific News; 2019, 138, 2; 93-112
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy efficiency analysis of railway turnout heating system with a melting snow model heated by classic and contactless heating method
Autorzy:
Flis, Mateusz
Powiązania:
https://bibliotekanauki.pl/articles/140565.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electrical heating
enthalpy method
experimental research
melting process
railway turnouts
thermal field
heat distribution
Opis:
Maintaining railway turnout operability is crucial for ensuring railway transport safety. Electric heating of railway turnouts is a significant technical and economic issue. The classical heating is characterised by high power consumption. For this reason, research is needed to optimise the current system. This paper presents results of a numerical analysis and of experimental researches. The numerical analysis was carried out using the ANSYS software. There was conducted a numerical comparative analysis of energy loss during heating performed using two different heaters. Including the classical method and a heater thermally insulated from a rail. In the first step, heating of a working space filled with a substitute snow model was considered. The snow-covered surface area was held within the working space of the turnout. It was assumed that the snow substitute material had thermal properties approximately the same as real light snow. It was also assumed that the material is in the solid state which would not undergo a phase change. In the next step, a real snow model that included the phase change process was taken into account. The energy efficiency and heat distribution in the turnout have been analysed and compared. The experimental researches were carried out in a physical model. The results showed that the use of a contactless heater results in creating a larger area over which emitted heat affected snow in the working space. Consequently, more snow was melted around the contactless heater than the classic one. This experimental observation supported the results of the numerical analyses presented previously.
Źródło:
Archives of Electrical Engineering; 2019, 68, 3; 511-520
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of thermal barrier coating on temperature and stress distribution in diesel engine
Wpływ bariery cieplnej na rozkład temperatur i naprężeń w silniku ZS
Autorzy:
Hejwowski, T.
Dębski, H.
Powiązania:
https://bibliotekanauki.pl/articles/245709.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
silnik ZS
MES (metoda elementów skończonych)
bariera cieplna
naprężenie cieplne
rozkład temperatur
diesel engine
thermal barrier coating
FEM
thermal stress
temperature distribution
Opis:
The paper presents results of FEM investigations into the effect of thermal barrier coating (TBC) on stress and temperature distributions in the components of naturally aspirated diesel engine. Calculations were performed by means of Abaqus ver. 6.8-3 computer program. The considered coating was plasma sprayed double-layered TBC consisting 0.15 mm thick NiCrAl bond layer and 0.3 mm ZrO2-8%Y2O3 top coat. TBC reduced the maximum temperature of the cylinder head by 15K compared to uncoated metal head, increased temperature of the outlet channel by 10 K and reduced maximum temperatures in inlet and outlet valves by 2 and 1.2 K, respectively. Although maximum temperature of the pis ton head remained the same after deposition of the coating but the range of temperatures at the piston head was reduced by 23.8%. Application o f TBC considerably reduced stresses in acritical region of outlet valve- the interface of stellite hardfacing /valve. The highest thermal stresses in the TBC were in the bondcoat, which confirms the common localization of damages. Stress concentrations were also found in the metal part at the edges of TBC and at the edges of the recess machined in the piston head. The reduction of metal temperatures and thermal gradients in protected components should have some positive effect on the components' durability.
W pracy przedstawiono rezultaty badań numerycznych wpływu powłoki typu bariery cieplnej (TBC) na rozkład temperatur i naprężeń w elementach wolnossącego silnika ZS. Obliczenia numeryczne zostały wykonane przy pomocy programu Abaqus wer. 6.8-3. Rozważano natryskaną plazmowo powlokę dwuwarstwową składającą się z warstwy podkładowej o gr. 0,15 mm i warstwy ceramicznej ZrO2-8%Y2O3 o grubości 0,3 mm. TBC obniżyła maksymalną temperaturę głowicy silnika o 15 K w porównaniu do głowicy nie pokrytej powłoką oraz obniżyła maksymalne temperatury zaworów wylotowego i dolotowego o 2 K i 1,2 K, odpowiednio. Wprawdzie maksymalna temperatura tłoka pozostała stała ale obniżył się o 23,8% zakres temperatur na powierzchni tłoka. Zastosowanie powłoki znacznie obniżyło wartość naprężeń w krytycznym miejscu zaworu wylotowego- granicy podłoża i warstwy napawanej stellitem Najwyższa wartość naprężeń TBC występowała w warstwie podkładowej co potwierdziło częstą lokalizację pęknięć. Znaleziono również koncentracje naprężeń na krawędzi TBC i krawędzi wybrania w denku tłoka. Obniżenie temperatur metalu i gradientów temperatur w pokrytych elementach powinno wydłużyć trwałość elementów.
Źródło:
Journal of KONES; 2009, 16, 4; 147-154
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 38

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