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Wyświetlanie 1-7 z 7
Tytuł:
Identification of fouling deposited on the heat transfer surfaces of the steam power plants heat exchangers
Autorzy:
Hajduk, T.
Powiązania:
https://bibliotekanauki.pl/articles/241825.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
steam power plant
heat exchanger
heat transfer surface deposit
spectral analysis
Opis:
The term “fouling” refers to a substance, which settles on the heat transfer surface and causes the rise of thermal resistance to the heat transfer process. Sometimes, fouling is regarded as deposit but that term should be only used to fouling in the form of solid. Taking the traditional division of matter states as a criterion for fouling classification, there are three sorts of fouling: the solid ones, e.g. boiler scale, metal oxides, mud; the liquid ones, e.g. lubricating turbine oil and the volatile ones, air as for example an inert gas. Despite maintaining the recommended methods of correction for the steam power plants working agents, such as: the feed water, the boiler water, the condensate and the water vapour, for example by using the phosphate-ammonia correction, both corrosion and deposition phenomena occur in the water and the steam sides of the heat exchanger. Recognition of the type and the amounts of deposits gathered on heat transfer surfaces of the steam power plants heat exchangers is used within the thermal-flow diagnostics and also supports the planning of overhaul and routine repair of these devices. The results of the author’s own experimental research based on the method of spectral analysis were presented in the paper. The study was carried out in order to identify the type of fouling settled on both the outer side (steam side) and the internal side (waterside) on the heat transfer surfaces.
Źródło:
Journal of KONES; 2016, 23, 4; 135-142
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An influence of fouling gathered on the heat transfer surfaces on the heat performance characteristics of the ship steam systems heat exchangers
Autorzy:
Hajduk, T.
Powiązania:
https://bibliotekanauki.pl/articles/1841551.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
marine power plant
gathering of fouling
heat transfer surface
heat performance characteristics
thermal resistance
heat trransfer
heat exchangers
Opis:
More than half of the incidents reported to EMSA relate to nautical events such as collision, groundings and contacts. Knowledge of accurate and high-integrity positioning is therefore not only a need for future automated shipping but a base for today’s safe navigation. Examples on accidents include Ever Given in the Suez Canal and HNoMS Helge Ingstad in Norway. A Network-RTK (NRTK) service can be used as an augmentation technique to improve performance of shipborne GNSS receivers for future positioning of manned and unmanned vessels in restricted areas, such as port areas, fairways, and inland water ways. NRTK service providers generate RTK corrections based on the observations of networks of GNSS reference stations which enables the users to determine their position with centimeter accuracy in real-time using a shipborne GNSS receiver. Selection of appropriate communication channels for dissemination of NRTK corrections data is the key to a secure positioning (localization) service. In PrePare-Ships project, the modern maritime communication system VDES (VHF Data Exchange System) is proposed to distribute SWEPOS (NRTK in Sweden) correction data to shipborne positioning modules. VDES is a very reliable technique and it is compatible with most onboard functionalities. In order to minimize the impact on the overall VDES data capacity in a local area, NRTK correction data shall only occupy a single VDES slot with a net capacity of 650 bytes. Update rates may vary but are preferably at 1Hz. However, NRTK correction data size changes instantly, depending on the number of visible GNSS satellites, and the data rate can therefore sometimes reach in excess of 1000 byte/s. In this study, a smart technique is proposed to reduce size of NRTK correction data to instantly adapt with the VDES requirements by choosing a combination of specific signals, satellites or even constellations such that the data rate is not more than 650 byte/s, and at the same time it achieves optimal positioning performance with the accuracy required by the PrePare-Ships project application.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2021, 15, 1; 183-189
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The assessment of surface layers texture of the fouling gathered on the heat transfer surfaces within regenerative feedwater heat exchangers
Autorzy:
Hajduk, T.
Powiązania:
https://bibliotekanauki.pl/articles/246269.pdf
Data publikacji:
2017
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
steam power plants
heat recovery devices
fouling
surface layer texture
Opis:
The fouling presence on the heat transfer surfaces, both on the waterside and the steam side of the steam power plants heat recovery exchangers usually leads to the loss of their heat transfer capacities. This loss appears owing to the high value of heat resistance of fouling. Furthermore, these deposits are most often formed with irregularities in the surface layers. These textures are usually characterized by a varied, often stochastic and difficult to define, geometric structures. The most common measure of their inequalities is the roughness parameter describing the surface geometry. The fouling surface layer texture can, on one hand, cause enhancement of the heat transfer process, but on the other hand, it may contribute to an additional increase in thermal degradation of the heat exchanger. Many experimental studies have shown that the greater the unevenness of the heat transfer surface on the waterside of a given heat transfer device, the smaller increase in the thermal resistance of the impurities over time, thereby increasing the amount of heat transferred. It should be emphasized, however, that the rise in roughness results in an increase in the heat transfer coefficient, while simultaneously intensifying the flow resistance of the working medium. Taking into account the heat transfer surface by steam side, the increase in the roughness promotes the formation of a thicker condensate layer, thus impairing the condensate drainage organization. It can be explained by the fact that deposits settle in a sort of quasi-rib effect, although with undefined ribbed grid, it may lead to the overflow of inter-finned passages. The article shows the previously mentioned phenomena and also presents the descriptive quantities for the fouling surface layer texture, based on the results of the author’s own experimental research.
Źródło:
Journal of KONES; 2017, 24, 4; 55-60
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of the thermal degradation process within the steam power plants heat exchangers
Autorzy:
Hajduk, T.
Powiązania:
https://bibliotekanauki.pl/articles/244895.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
steam power plants
fouling of heat transfer surface
thermal degradation determinants
Opis:
The consequence of the deposits presence on the heat transfer surface of the following heat exchangers: shell-and-tube condensers, the regenerative feed water exchangers, are commonly the loss of heat exchanger capacity, owing to the high value of heat conductive resistance of fouling. The process is more often defined as the thermal (heat) degradation of a given heat transfer device. The symptoms of heat degradation are usually defined as the difference between the values of thermal-flow parameters for the current and the reference state. Moreover, this process always entails an increase in the cost of energy conversion, leading to increasing the emission output of greenhouse gases consequently increasing the environmental degradation. It is worth mentioning that deposits settled on the waterside of heat transfer surface could also initiate the process of tubes obliteration. This phenomenon is characteristic for condensers cooled by seawater in particular. Reducing internal diameter of any single heat exchanger pipe by the deposits cause the rise in flow resistance and also reduce the condenser cooling water pump capacity. Ultimately, it leads to the reduction in water flow rate, resulting in an additional increase in the resistance of heat transfer. Furthermore, reducing the flow rate of cooling water causes the enhancement of the fouling settling rate. The paper describes the above-mentioned phenomena and presents the quantitative determinants of the thermal degradation description for heat exchangers based on the results of the author’s own experimental research.
Źródło:
Journal of KONES; 2016, 23, 4; 127-133
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research of deposit accumulated on heat exchange surfaces in the light of thermal degradation of heat exchange aparatus of steam power plants. Part I: study of real sediment
Autorzy:
Hajduk, T.
Powiązania:
https://bibliotekanauki.pl/articles/260631.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
steam power plants
heat exchangers
deposits
spectral analysis
surface geometric texture
Opis:
The presence of deposits on heat exchange surfaces in condensers and regenerative exchangers of ship and land steam power plants is always connected with the increase of the wall temperature on the water vapor side due to additional thermal resistances resulting from accumulated deposits. This increase always results in an increase in the condensing pressure, which results in the deterioration of the condensation process of the water vapor, leading to thermal degradation of a given heat exchanger. In addition, the resulting deposits form unevenness with a diversified, often stochastic, geometric structure of the surface layer surface, whose measure is most often the roughness parameters, describing the geometric structure of the surface. In addition, the increase in surface roughness of the heat transfer surface on the water vapor side promotes the formation of a thicker layer of condensate, thus worsening the organization of condensate runoff, which results in interference of the thermal degradation phenomenon of a given heat exchange apparatus. As a result, these phenomena lead to a reduction in the efficiency of a given thermal system, and thus entail an increase in the costs of energy conversion and consequently cause an increased degradation of the natural environment. In the article, based on the results of the author’s own experimental research, the types of pollution accumulating on heat exchange surfaces on the water vapor side of heat exchange apparatus in marine and land steam power plants and quantitative measures of the unevenness of the surface layer of these sediments are presented.
Źródło:
Polish Maritime Research; 2018, 1; 99-107
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determinanty procesu degradacji termicznej aparatów wymiany ciepła w siłowniach parowych
The Heat Exchanger Thermal Degradation Process Determinants within the Steam Power Plants
Autorzy:
Hajduk, T.
Powiązania:
https://bibliotekanauki.pl/articles/342415.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Morski w Gdyni. Wydawnictwo Uniwersytetu Morskiego w Gdyni
Tematy:
siłownie parowe
wymienniki ciepła
degradacja cieplna
steam power plants
heat exchangers
thermal degradation
Opis:
Obecność zanieczyszczeń na powierzchniach wymiany ciepła aparatów wymiany ciepła w okrętowych i lądowych siłowniach parowych jest przyczyną m.in. wzrostu spiętrzeń temperatur oraz związanego z tym pogorszenia stopnia próżni w skraplaczach. W końcowym efekcie proces degradacji termicznej wymienników ciepła prowadzi do zmniejszenia sprawności danego układu cieplnego. Symptomy degradacji termicznej najczęściej definiowane są jako różnica między wartościami parametrów cieplno-przepływowych dla stanu referencyjnego i wartościami dla stanu aktualnego. W efekcie końcowym zjawisko degradacji cieplnej pociąga za sobą wzrost kosztów przetwarzania energii, a w konsekwencji prowadzi do zwiększonej degradacji środowiska naturalnego. W artykule opisano powyższe zjawiska oraz zaprezentowano determinanty degradacji termicznej wymienników ciepła siłowni parowych, opierając się na rezultatach własnych badań eksperymentalnych.
he deposits presence on the heat transfer surfaces of the heat exchangers within the stationary and the ship steam power plants cause an inscrease in terminal temperature difference values and entails a decrease of the vacuum level, as well. That fact leads to reducing the total efficiency of the thermal unit. Symptoms of heat degradation are usually defined as the difference between the values of thermal-flow parameters for the current and the reference state. Moreover, thermal degradation of any heat transfer device always entails an increase in the cost of energy conversion, leading to increasing the emission output of greenhouse gases and finally increasing the environmental degradation process. The above-mentioned phenomena, the determinants of the thermal degradation as well as the results of the author’s own experimental research have been presented in the paper.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Gdyni; 2017, 100; 87-99
1644-1818
2451-2486
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Gdyni
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ocena mocy cieplnej aparatów wymiany ciepła siłowni parowych dla różnych stanów ich użytkowania w aspekcie degradacji termicznej
The Thermal Power Appraisal of Steam Power Plant Heat Exchangers for Their Various Operating Modes in the Aspect of Their Thermal Degradation
Autorzy:
Hajduk, T.
Powiązania:
https://bibliotekanauki.pl/articles/341593.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Morski w Gdyni. Wydawnictwo Uniwersytetu Morskiego w Gdyni
Tematy:
siłownie parowe
skraplacze
wymienniki regeneracyjne
degradacja cieplna
użytkowanie wymienników ciepła
steam power plants
condensers
heat recovery exchangers
thermal degradation
operating modes of heat exchangers
Opis:
Odkładające się osady na powierzchniach wymiany ciepła wymienników ciepła w okrętowych i lądowych siłowniach parowych są przyczyną m.in. wzrostu spiętrzeń temperatur oraz związanego z tym pogorszenia stopnia próżni w skraplaczach. Proces degradacji termicznej prowadzi zawsze do zmniejszenia strumienia cieplnego transportowanego przez wymienniki, a w końcowym efekcie do zmniejszenia sprawności danego układu cieplnego. Okazuje się jednak, że utrata mocy cieplnej wymiennika ciepła nie zależy tylko od wartości samych oporów ciepłych osadów, ale jest również ściśle skorelowana z atrybutami cieplnymi wymiennika ciepła, tj. wartościami współczynnika przenikania ciepła w różnych stanach eksploatacyjnych wymiennika. W artykule opisano powyższe zjawiska oraz zaprezentowano rezultaty własnych badań eksperymentalnych.
The fouling presence on the heat transfer surfaces of the heat exchangers within the stationary and the ship steam power plants cause an increase in terminal temperature difference values and entails a decrease of the vacuum level, as well. The thermal degradation process always leads to reducing the thermal flux transported by the heat exchangers and decreasing total efficiency of the thermal unit, finally. It turns out, however, that the loss of thermal power of a heat exchanger does not only depend on the fouling thermal resistance but is also closely correlated with the thermal attributes of given heat exchanger, i.e. the heat transfer coefficient values at various operating conditions for that heat exchanger. The article describes the above-mentioned phenomena and presents the results of the author’s own experimental research.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Gdyni; 2018, 108; 43-54
1644-1818
2451-2486
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Gdyni
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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