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EN
This article presents the results of investigations focused on the role of molecularly ordered structures (molecular clusters) on combustion process. The proposed new mechanism of the reactions initiation takes into account the role of molecular clusters in energy (heat and energy of electrons emitted by the surface of the walls of combustion chamber) conductivity regulation. Literature survey shows that molecular clusters created by aromatic hydrocarbons are responsible for particulate matter. The combustion process itself is not uniform in whole combustion chamber. Such diversity, caused mainly by heterogeneous thermal state of combustion chamber is recognized as significant reason to create various products of combustion including carbon oxides, carbon dioxides and nitrogen oxides. Jet fuel and its blends with n-butanol and biobutanol in concentration from 10 to 75 % (V/V) were subjected to laboratory tests. Such blends were also tested on the test rig with a miniature turbojet engine – MiniJETRig. Engine operating parameters and carbon oxide emission were measured. The relations between electrical conductivity and parameters of engine test (e.g. temperature in selected points in combustion chamber) were assessed. Engine tests were carried out according to specific profile of engine test, which models different engine operating modes. The results of experimental investigations, shown in the article, initially confirm the proposed mechanism of the oxidation reactions initiation during combustion process.
EN
Hydrocarbon containing synthetic fuels represent a promising alternative fuels. Despite different chemical compositions, their properties should be similar to properties of mineral fuels, as they are designed for the same drive units. The basic parameter related to the protection of the adequate service life of the power supply devices, including precision pairs, is lubricity. Lubricity depends on a number of factors, including these related to the chemical composition of fuel components and operating additives introduced into fuels in order to modify their properties. The preliminary results of research on the effect of additives: lubricating, anti-corrosion and anti-electrostatic once, on the lubricating properties of a synthetic fuel are shown in the paper. It was observed that there are relations between the content of additives and the dynamics of film formation. It is significant that this does not apply only to the lubricating additive, but also the additive, which protects the correct electrostatic balance by providing sufficiently high electrical conductivity of the fuel. This may indicate that the formation of a lubricating film remains in relation to the intensity of energy transport from the lubricated surface to the molecules of lubricating additives inside the film. The results shown in the paper preliminary confirm the hypothesis, that synthetic components of fuels change the concentration of ordered molecular structures (which are present in mineral part of fuels and which can be responsible for energy transport inside the lubricating film), what resulted in worse fuel ability to create protective film, and anti-electrostatic additive improves lubricity of blends of synthetic and mineral components.
EN
The topic of developing a methodology and a stand test for the evaluation of materials intended for the construction of tribogenerators has been actualized in this article. The proposed method concerns the use of sliding friction in the course of which the mechanical energy is converted into electric energy using the triboelectric and electrostatic effect. The stand test scheme and research methodology are discussed. A preliminary study of friction pairs was carried out, proving the effectiveness of the methodology.
PL
W artykule opisano metodykę i stanowisko do oceny materiałów przeznaczonych do budowy tribogeneratorów. Zaproponowana metoda dotyczy przypadku wykorzystania tarcia ślizgowego, w trakcie którego energia mechaniczna zamienia jest na energię elektryczną z wykorzystaniem efektu tiboelektrycznego i elektrostatycznego. Omówiono schemat budowy stanowiska oraz metodykę badań. Przeprowadzono wstępne badania par ciernych, udowadniając skuteczność metodyki.
EN
This paper presents results of tribological tests performed under lubricated friction conditions using a T-01M analyser. The lubricant was biodegradable cutting fluid containing a special-purpose additive – zinc aspartate. The discs for the ball-on-disc configuration were made of HS6-5-2C steel. The study involved testing coated and uncoated steel specimens. The a-C:H and TiAlN coatings were produced using physical vapour deposition (PVD). The structure of the coatings was analysed before and after the tribological tests with a JSM-7100F scanning electron microscope. The coating hardness was measured using a CSM Instruments nano-hardness tester (NHT). The coating surface texture of the coated and uncoated discs was determined by means of a Talysurf CCI Lite profilometer. The thin boundary films that formed in the friction area prevented the surfaces from coming into direct contact. The films improved the motion resistance and provided anticorrosive protection during the tests. The biodegradable cutting fluid used in the study had no negative effect on the environment.
PL
W artykule zestawiono wyniki badań tribologicznych wykonane na testerze T-01M w warunkach tarcia ze smarowaniem biodegradowalną cieczą chłodząco-smarującą zawierającą dodatek uszlachetniający – asparginian cynku. Tarcze były wykonane ze stali HS6-5-2C bez i z naniesioną powłoką a-C:H oraz TiAlN techniką fizycznego osadzania z fazy gazowej PVD. Obserwacje struktury powłok przed testem tribologicznym wykonano mikroskopem skaningowym SEM JSM-7100F. Twardość powłok przed testem tribologicznym zmierzono za pomocą nanotwardościomierza NHT CSM Instrument. Natomiast analizę struktury geometrycznej powierzchni tarcz bez powłoki i z powłokami przed oraz po testach tribologicznych wykonano profilometrem optycznym Talysurf CCI Lite. W miejscu tarcia powstały warstwy graniczne, które zabezpieczyły przed bezpośrednim kontaktem powierzchni współpracujących tarciowo. Warstwy te przyczyniły się do zmniejszenia oporów ruchu oraz zapewniły ochronę antykorozyjną w czasie prowadzenia testów. Ponadto użyta do badań ciecz chodząco-smarująca jest biodegradowalna i nie wykazała negatywnego wpływu na środowisko.
EN
The paper covers the mechanism of lubrication layer formation by fuels containing synthetic hydrocarbons and alcohols. Development of alternative fuels containing FAME, alcohols, and synthetic hydrocarbons has increased the interest in the mechanism of lubrication of fuelling systems parts. Fuel lubricity tests have been conducted using the HFRR and BOCLE testing rigs. Fuels under testing, both for CI engines and for aviation turbine ones, contained synthetic components: saturated hydrocarbons both of even and odd number of carbon atoms, and butanol, isomers. These components have been added to conventional fuels, such as diesel fuel and Jet A-1 fuel at the concentration of 0–20% (V/V). All fuels under testing contained commercially available lubricity improvers (carboxylic acid). Test results were analysed using model αi described in [L. 6, 7]. As a result of the analysis, it has been found that the liquid phase, which is a lubricating film, should contain agglomerates or molecular clusters responsible for the transport of energy introduced into lubricating film by electrons emitted from metal surface. The mechanism enabling a description of the effect of base fuel without lubricity improvers on efficiency of such additives has been suggested.
PL
Przedmiotem artykułu jest mechanizm tworzenia warstwy smarującej przez paliwa zawierające syntetyczne węglowodory i alkohole. Rozwój paliw alternatywnych spowodował wzrost zainteresowania mechanizmem smarowania elementów układów zasilania silników. Badania smarności paliw prowadzono z użyciem aparatów HFRR i BOCLE. Badane paliwa do silników o ZS i paliwa do turbinowych silników lotniczych zawierały trzy serie syntetycznych komponentów: węglowodory parafinowe o parzystej liczbie atomów węgla, węglowodory parafinowe o nieparzystej liczbie atomów węgla oraz izomery butanolu. Powyższe syntetyczne komponenty były dodawane do mineralnych paliw: oleju napędowego i paliwa Jet A1 w ilości 0–20% (V/V). Wszystkie badane paliwa zawierały komercyjnie dostępne dodatki smarnościowe (kwas karboksylowy). Wyniki badań eksperymentalnych były analizowane z zastosowaniem modelu αi opisanego w publikacjach [L. 6, 7]. W rezultacie przeprowadzonej analizy stwierdzono, że faza ciekła – film smarny powinna zawierać aglomeraty lub klastry molekularne, które są odpowiedzialne za transport energii wprowadzanej do filmu smarnego przez elektrony emitowane z powierzchni metalu. Zaproponowano mechanizm, który może wyjaśnić wpływ paliwa bazowego (bez dodatków smarnościowych) na efektywność działania dodatków smarnościowych.
EN
This article compares the test results concerning the wear of cutting tools after face turning under dry friction conditions and lubricated friction conditions with biodegradable cutting fluid or mineral-oil based emulsion. The turning was performed using a CTX 310 ECO machine tool. The wear of the cutting tools was measured by means of stereo zoom microscopy (SX80), while the elements were identified through scanning electron microscopy (JSM 7100F). The tribological tests were conducted for a ball-on-disc configuration in sliding contact using a T-01M tribometer. The surface textures of the face turned specimens were measured with a Talysurf CCI Lite optical profiler. The study also involved determining the foaming tendency and corrosive effects of both cutting fluids. The use of the biodegradable cutting fluid with low foaming tendency resulted in lower wear and higher corrosion resistance of the tool.
PL
W artykule przedstawiono wyniki badań zużycia narzędzi skrawających po procesie toczenia czołowego w warunkach tarcia technicznie suchego, ze smarowaniem biodegradowalną cieczą obróbkową oraz emulsją opartą na oleju mineralnym. Badania wykonano na tokarce CTX 310 ECO. Po obróbce zmierzono zużycie narzędzi za pomocą stereoskopowego mikroskopu inspekcyjnego SX80, a identyfikację pierwiastków przeprowadzono z użyciem skaningowego mikroskopu elektronowego JSM 7100F. Testy tribologiczne wykonano na urządzeniu T-01M. Pomiary struktury geometrycznej powierzchni elementów toczonych czołowo wykonano profilometrem optycznym Talysurf CCI Lite. Dodatkowo przeprowadzono badania pienienia i korozji cieczy obróbkowych. Zastosowane w badaniach biodegradowalne chłodziwo wpłynęło na zmniejszenie wybranych wskaźników opisujących zużycie narzędzia, a także zapewniło lepsze właściwości przeciwkorozyjne oraz przeciwpienne.
EN
Recent events in Ukraine related to Russia’s impact on some regions of this country raised concerns in the international security environment, not only focused on this region, but in a broader, international aspect. Complex internal situation of Ukraine, as well as Kremlin’s aspirations to constantly strengthen its position as a major player on the international politics stage, caused a stalemate in a resolution of such serious problem as jeopardizing the security of not only Ukraine, but the international one as well.
EN
The aim of this article is presentation of the new method of preliminary evaluation of biocomponents influence on the process of biofuels combustion in aviation turbine engines. This method is based on the tests of evaluated biofuels on engine stand MiniJetRig equipped with small turbine engine. The idea of this new method is to compare the combustion process of evaluated biofuel with the combustion of reference fuels. The reference fuel used in presented research was mineral Jet A1. Two compositions of pure hydrocarbons were blended with Jet A1 fuel and tested using MiniJetRig. The main criterion of combustion process assessment was CO concentration in exhaust gases. As the final criterion of evaluated biofuel the ΔCO = [COWx – COJet] was adopted, where COWx – the concentration of CO in exhaust gases emitted during combustion of evaluated fuel and COJet – the concentration of CO in exhaust gases emitted during combustion of Jet A1 fuel. This method was preliminary verified using HEFA biofuel previously accepted for aviation application. The obtained results qualify this biofuel as similar to Jet A1 ones – the DCO was within limits –30 – +20. The presented method needs further research, using much more evaluated fuels, to confirm their usefulness for laboratory pre-selection of new biofuels.
EN
The aim of this paper is presentation of the possibility of combustion processes modelling so that to better describe the influence of fuels chemistry on fuels combustion. This is important for prediction the behaviour of different alternative fuels in processes in combustion chamber. Currently used mathematical models do not sufficiently take into account the influence of fuels chemical composition on combustion process. The idea of new mathematical model is proposed in this paper. The paper presents the main assumptions of this model and the results of its preliminary verification using MiniJetRig.
EN
This paper discusses briefly the production technology of dimethyl ether, taking into account plant raw materials and the physical and chemical properties of DME as compared to diesel fuel. The benefits and disadvantages of DME as a fuel are presented and changes in the emission of harmful substances characterised as compared to the combustion of diesel fuel. Also, basic usage problems are addressed, e.g. the wear of engine’s elements, cavity and leakages in the fuel system.
EN
In the paper, the concept of a model bench for accelerated ageing of bio-components and biofuels was presented. It is used to simulate the ageing process of biofuels and components of vegetable or animal origin, taking place during storage in the storage tanks. The construction of the bench’s essential elements and its equipment were designed and implemented in such a way as to mostly reflect actual storage conditions in large capacity tanks. An additional and unprecedented function of the bench includes the possibility to simulate the product transport conditions. Furthermore, a method of the test, with the use of simultaneously performed traditional tests on the physical and chemical properties monitored in the process of storage was presented. An analysis of the relation between values of the parameters obtained with different methods (on the model bench and under laboratory conditions) was conducted. In addition, their usefulness to assess the impact of logistic processes on the product quality was presented. In the paper, the results of the work executed within the framework of the project “Development of a prototype of the monitoring system the ageing rate and degree of bio-components and biofuels” within the Program Innovative Economy Operational Programme, Measure 1.4. “Support for goal-oriented projects” were used.
EN
The paper presents the results of investigations concerning a new method used for predicting the allowable time of storage of biocomponents – FAME. The method was based on laboratory research carried out with the use of a storage tank simulator. The aging process was carried out in the conditions increasing the reaction rate – at high temperature. There are several methods/procedures used for predicting the allowable time of storage of fuels and biocomponents – FAME, but all of them are based on tests at the temperature so high that the mechanism of aging process is different than the one observed in storage tanks. It was assumed that the aging process could be divided into two stages: at the first stage, the aging precursors are created and at the second stage, precursors are converted into the fuel aging products. These products lead to changes in fuel properties. The kinetics of precursor creation determines the rate of all reactions, which lead to the final aging products. It was found that the rate of reaction at the first stage of fuel aging can be effectively increased by an increase in temperature and even relatively high temperature does not change the mechanism of the creation of aging precursors. The method that has been worked out makes it possible to control the mechanism of aging process during quick laboratory tests. The products of aging processes were detected with the use of the IR-VIS spectrometry. The allowable time of storage was determined for several FAME samples on the basis of quick laboratory tests. The results of laboratory quick tests were verified by comparing them with the results of the aging process of FAME in storage tanks. On the basis of the test results, the algorithm of allowable time of FAME storage calculation was worked out.
EN
The aim of this paper is to examine the current views on the mechanism of the formation of a protective film by mineral fuels and biocomponents (FAMEs and alcohols). As the experimental data show, the ability of fuels / biofuels to form a protective film under different conditions is very important to the efficient operation of fuel pumps. The mating parts of pumps are protected against wear and seizure because of the interactions between the metal surfaces and the lubricant (fuel / biofuel) at the molecular level. The tribochemical research focuses on the tribochemical reactions of lubricating additives because the base fuel is frequently treated as a solvent only. Today, most fuels for CI engines contain FAME, a biocomponent that may differ in the chemical structure depending on the type and properties of the vegetable oil used. The current trend is to produce fuels from biomass hydrocarbons, which are blended with mineral diesel fuel. It has been found that the chemical structure of biohydrocarbons is responsible for changes in the lubricity of the blends. Lubricity is determined using a standard high frequency reciprocating rig (HFRR) test because of one parameter, i.e. the wear of the ball. The results of the authors’ previous studies were used to create a new model of the protective film formation by fuels containing biocomponents (oxygenates) and biohydrocarbons. The model makes it possible to describe the tribochemical processes quantitatively. The quantitative analysis is based on the parameter αi, which is the measure of reactivity of lubricating additives and/or biocomponents related to the properties of the mating parts and the operating conditions in a tribological system. The new approach to the mechanism of the protective film formation, based on the quantitative description of tribochemical reactions, enables us to begin research on new criteria for the lubricity of fuels containing lubricating additives and biocomponents.
PL
artykule omówiony został problem starzenia chemicznego biokomponentów do paliw silnikowych. Problem ten stał się ważny dla jakości benzyn i oleju napędowego w sytuacji powszechnego dodawania bioetanolu i FAME. Badaniami objęto bioetanol i FAME przechowywane w różnych warunkach w laboratorium. Zastosowano do oce-ny stopnia zestarzenia biokomponentów standardowe metody badań oraz analizę spektroskopową w zakresie IR i chromatografię gazową. Przedstawiono wyniki badań bioetanolu i FAME przechowywanych przez 1 rok oraz wyniki analiz próbek bioetanolu i FAME przechowywanych w warunkach laboratoryjnych w różnych warunkach. W wyniku przeprowadzonych badań stwierdzono, że proces starzenia bioetanolu przebiega poprzez aldehyd octowy i acetal, a FAME trójetapowo poprzez epitlenki i nadtlenki. Stwierdzono także, że zanieczyszczenia biokomponentów, tj. woda i stałe produkty korozji zbiorników magazynowych przyspieszają procesy starzenia biokomponentów.
EN
The article explains the chemical processes responsible for aging of biocomponents during their storage. This problem is import ant for quality of gasolines and diesel fuel. The study involved bioethanol and FAME stored under different conditions in the laboratory. The standard methods and IR spectroscopy as well as gas chromatography were use for aging processes assessment. The obtained results showed that aging process of bioethanol runs through aldehyde and acetal. Aging of FAME runs through three stages which comprise epioxides and peroxides. It was found that water as well as solid contaminants increase the ratio of aging processes of bioethanol and FAME.
EN
A worldwide trend to popularise gradually increasing use of biofuels in various applications was a motivation for gaining interest in FAME as a commonly available biocomponent to fuels combusted in turbine engines. These engines are mainly used in aeronautics, but many of them are also used in other, non-aeronautical areas, including marine navigation. Specific conditions in which fuels are combusted in turbine engines used in these applications are the reason why fuel mixtures of kerosene and FAME type should reveal relevant low temperature characteristics. The article presents results of tests of low temperature properties of mixtures of the jet fuel Jet A-1 and methyl esters of higher fatty acids (FAME). The prepared mixtures contained different contents of FAME. The obtained results present changes of: viscosity, cloud point, pour point, crystallising point, and cold filter plugging point, depending on the percentage by volume of FAME. They also prove that the course of changes of low temperature properties of these mixtures is affected by chemical structure of the biocomponent.
EN
Lubricity of fuels for CI engines becomes one of very important parameter since the sulphur content was decreased to 50 and actually 10 ppm. To provide effective lubrication of fuel pumps and unit injectors elements, in case fuel does not contain organic sulphur compounds, the oxygen containing organic compounds are added as lubrication additives. Biocomponents are usually introduced into mineral diesel fuel containing additives package, which includes lubricating additive (organic acid). The aim of this paper is investigation of the influence of polar oxygenates added to petroleum diesel fuel in concentration between 5 and 20% (V/V) on lubricating additive effectiveness in protective layer creation. The results of HFRR tests obtained for blends of commercial diesel fuel containing lubricating additive with biobuthanol models (MB) leads to conclusion that: − generally the buthanol isomers addition increases wear of upper ball of HFRR apparatus, − wear of upper ball of HFRR apparatus depends on the average film thickness and does not depend on tested fuels viscosity at 40°C, − dilution of commercial diesel fuel by biobuthanol models and consequently decreasing of lubricating additive concentration cannot be the only reason of deterioration of tested blends lubricity. It was concluded, that the possible reason of lubricity deterioration by buthanol added to commercial diesel fuel in concentration between 5 and 20% (V/V) are antagonistic interactions between oxygenates (buthyl alcohol) and lubricating additive. These antagonistic interactions depend on the structure of buthanol isomers.
17
Content available remote On the mechanism of catalysis induced by mechano-activation of solid body
EN
The paper presents a new model of the mechanism of mechanocatalysis and tribocatalysis. The reason for the increase in heterogeneous catalysis effect after mechanical activation of a catalyst has not been fully understood yet. There is no known theory, which would explain the mechanism of the influence of mechanical energy introduced to catalyst particles on the rate of chemical reaction. All existing theories are based on Arrhenius equation and assume that catalysts increase reaction rate due to decreasing of activation energy Ea. We hypothesize that both for standard and catalyzed heterogeneous reactions the same Ea (real activation energy) is needed to trigger the reaction processes and the catalytic effect is the result of energy introduced to the reaction system, its accumulation by a catalyst and then emission of high flux of energy to the space near the catalyst particles. This energy emitted by molecules of reagents can reach a value equal to the value of Ea at lower ambient temperature than it would result from Arrhenius equation. This hypothesis is based on αi model described in previous papers by Kajdas and Kulczycki as well as the results of tribochemical research described by Hong Liang et al., which demonstrate that the reaction rate is higher than that resulting from temperature.
EN
Research of usefulness of fuels for long-term storage is an important research of products of special use (meant for stock keeping as national or military reserves). Important fact is that fuels after storage should be used according to their initial use so their phisico-chemical and exploratory properties should remain the same during the whole storage cycle. Basic condition, enabling to foreseen that fuel will keep its quality at sufficient level in certain timeframe should be positive results of ageing tests. Below the doubts are presented whether methodology of evaluation is correct because of important differences in mechanisms of accelerated laboratory tests as well as real storage in typical conditions of storage tanks with large capacity. Differences in courses of chemical reactions and conditions of their initiation and course were pointed out. Scheme of equipment for marking content of existing gums, scheme of equipment for testing induction period, scheme of filtering and oxidizing equipment to test resistance of fuel to oxidation, effectiveness of collisions of molecules of reactants, scheme of chemical ageing process of fuels storaged in different temperature, function for different conditions ageing process of FAME, influence of value of potential molecules energy on initializing of chemical reactions are presented in the paper.
EN
This paper describes the analysis and conclusions regarding the use of butanol/biobutanol as a component of conventional mineral fuels employed in different areas of transportation. Butanol from biomass - biobutanol is interesting as biocomponent of gasoline, diesel fuel as well as aviation fuels. This is especially important in case of air transport, which is the carbon dioxide emission source of the fastest growth. Biobutanol is tested as biocomponent of gasoline, including aviation ones, but there are no information about biobutanol added to mineral Jet fuel as well as diesel fuel. Direction of research conducted by leading aviation companies indicates that hydrocarbon biocomponent will be main biofuel used as aviation turbine fuel. One of reported technology is focused on use of butane-1-ol as semi-finished products for isoparaffinic hydrocarbons generation that then would be used for aviation turbine fuels production. In order to do such analysis the preliminary lab testing of blends of butanol isomers with aviation fuel Jet A-1 and diesel fuel were performed. The paper contains the results of standard tests for blends of mineral fuels with butane-1-ol and butane-2-ol added in concentration of 0-20 %(V/V). Both the advantages and disadvantages regarding the use of such component of mineral fuels are presented. Butanol decreases value of flash point and significantly influence on conductivity of Jet fuel. In case of aviation fuel for turbine engines, and diesel fuel, the restrictions regarding direct use of butanol are important. However, butanol can be treated as semi-finished material for synthesizing of biohydrocarbons used in above applications.
PL
Współcześnie produkowane paliwa zawierają, zależnie od gatunku, różnego rodzaju biokomponenty, takie jak: estry metylowe kwasów tłuszczowych, alkohole, etery. Związki te są dodatkowymi czynnikami inicjującymi i nasilającymi toczące się w paliwie procesy starzenia, w wyniku których produkt ulega zmętnieniu oraz rozwarstwieniu. Wiadomo, że magazynowane paliwa powinny być przechowywane w stałej temperaturze. Zmiany temperatury powodują wiele niekorzystnych procesów. Szybkość i częstotliwość tych zmian sprzyja nagromadzaniu się tlenu i wody w zbiornikach magazynowych na skutek specyficznego zjawiska „pompowania” lub „wtłaczania”. Jednak pomimo zachowania optymalnych fizykochemicznych warunków magazynowania, paliwo będzie zawsze ulegać procesom degradacji bez względu na przedsięwzięte środki zabezpieczeń.
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