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Gdańsk University of Technology

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Publications from the year 2023

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  • Water-Lubricated Journal Bearings Marine Applications, Design, and Operational Problems and Solutions
    • Wojciech Litwin
    2023

    Water-Lubricated Journal Bearings: Marine Applications, Design, and Operational Problems and Solutions provides cutting-edge design solutions, common problems and methods for avoiding them, and material selection considerations for the use of water-lubricated journal bearings in marine environments. These bearings have many advantages, including the absence of the potential for oil contamination. They are also sensitive, and their production processes can be challenging, but this book outlines techniques and concepts designed to overcome these challenges, emphasizing their role in durable and reliable propulsion systems in modern, safe, and environment-friendly shipping.Propeller shafts, water-lubricated stern tube bearings, problems frequently encountered with water-lubricated propeller shaft bearings and sliding bearings alongside solutions to these problems are all covered, as are the hydrodynamic properties of water-lubricated bearings, operation at low revolution speeds, high-speed bearings, hybrid bearings, and more. Foundational concepts of tribology related to friction, lubrication, wear, and fluid/solid and solid/solid interactions in ship stern tube and water-lubricated turbine machinery are also discussed.

  • WAYS TO IMPROVE THE EFFICIENCY OF WASTEWATER TREATMENT OF A CARDBOARD AND PAPER MILL
    • Larysa Sablii
    • Veronika Zhukova
    • Jakub Drewnowski
    2023 Full text ENVIRONMENTAL PROGRESS

    The results of research on physical and chemical methods for the preliminary treatment of wastewater of a cardboard and paper factory in Khmelnytskyi region of Ukraine are presented. At the cardboard and paper factory, wastewater is treated at a sewage treatment plant, which includes sand traps, primary radial sedimentation tanks, aeration tanks with activated sludge regenerators, secondary radial sedimentation tanks, and bioponds. The use of coagulation and chlorination methods before biological treatment in aeration tanks was proposed. Alumoflock 18 % was used as a coagulant, polyacrylamide was used as a flocculant, and sodium hydroxide was used as an alkalizing reagent. The study was conducted on a mixture of industrial and domestic wastewater with COD and BOD5 – 3200 and 1575 mg/dm3, respectively, and on industrial wastewater with COD and BOD5 – 4480 and 1960 mg/dm3, respectively. The effects of reducing COD and BOD5 indicators in the first case after coagulation were 30 and 40 %, after chlorination - 37.81 and 43.17 %, respectively, in the second after coagulation – 28.57 and 47.24 %, respectively. It was established that a significant proportion of organic substances according to the COD indicator is in a dissolved state – 60–70 %. It has been proven that as a result of chlorination, the maximum reduction of “pure” COD is achieved, therefore, the possibility and expediency of chlorination of water after the secondary settling tank with increased doses should be considered in the wastewater treatment technology of the cardboard and paper factory.

  • Western Front of the City Centre of Gdańsk. An Urban Conservation Study
    • Łukasz Bugalski
    2023

    The western front of Gdańsk`s city centre is the key fragment of a ring road scheme, which was created at the turn of the 20th century during the great transformation of the city. It was at that time that new streets and squares were delineated on the site of the early modern earthen bastions, which for more than three centuries marked Gdańsk`s border. The new city development was set up in their surroundings. In 1945, Gdańsk was destroyed and attempts at its redevelopment were undertaken after the war. The majority of the prepared designs were not implemented at all or were implemented fragmentarily only, which led to a visible degradation of the western front, which currently functions mainly as a thoroughfare. Łukasz Bugalski undertakes an effort to read the subsequent layers making up the urban heritage inscribed in the urban structure of the western front of Gdańsk's city center. Analysing the urban plans, designs and concepts, he provides evidence that the area - although currently rather chaotically organised - has a huge potential.

  • What should we know when choosing feather, blood, egg or preen oil as biological samples for contaminants detection? A non-lethal approach to bird sampling for PCBs, OCPs, PBDEs and PFASs
    • Aneta Pacyna-Kuchta
    2023 Full text CRITICAL REVIEWS IN ENVIRONMENTAL SCIENCE AND TECHNOLOGY

    Birds are considered as good bio-monitors and they can provide highly valuable data about the level of contamination in their habitat. During the design of biomonitoring studies one of the first issues after choosing species is the choice of biological material. Non-lethally collected samples have recently been gaining greater attention as they offer several ethical and practical advantages. However, not all sample matrices are suitable for biomonitoring of certain compounds. The main aim of this review is to bring to closer attention the utility of non-lethally collected samples from avian species, based on recent literature. The selected samples are feathers, blood, preen oil and eggs, as these are the types of biological materials most often chosen and may reveal birds’ exposure from their diet. It is not my intention to single out one of them as the ultimate tool for organic compound analysis, but rather to present their utility in order to support or advise on future choices, as a single matrix might not be sufficient to fully evaluate birds’ exposure. Therefore, this paper presents the current status of the non-lethal approach in avian species for determination of PCBs, OCPs, PBDEs and PFASs

  • When all we have is not enough: a search for the optimal method of quantifying inflation expectations
    • Aleksandra Rutkowska
    • Magdalena Szyszko
    • Michał Pietrzak
    2023 Full text Economic Research-Ekonomska Istrazivanja

    Although inflation expectations are pivotal variables for central banks, they are not directly observable. Therefore, central banks use qualitative survey results to proxy consumer expectations, and their quantification in this manner is often criticized. In this study, we investigate and identify an optimal quantification procedure for survey results based on a set of regression and probabilistic models. Specifically, we seek to identify the method that returns time series that are most highly correlated with an unbiased representative of survey-based expectation: balance statistics. We place additional constraints on this criterion to identify the procedure that returns expectations that are most closely related to consumer intentions (directional co-movements and forecast accuracy). Our sample covers the European Union member states over the period of January 2002 to June 2019. We also test a post-crisis subsample. Our results suggest that different procedures may be optimal for different economies, in line with previous findings on cross-country divergences of expectations formation. However, we find that the most applied assumption of normal distribution does not prove to be the best one. Our recommendation is to apply probabilistic procedures rather than regression methods.

  • Where the Second World War in Europe broke out: the land-scape history of Westerplatte, Gdańsk/Danzig
    • Wojciech Samól
    • Szymon Kowalski
    • Arkadiusz Woźniakowski
    • Piotr Samól
    2023 Full text Land

    Westerplatte is known as the place where the Second World War in Europe broke out. However, its history covers many other events involving Polish, German, Russian and even French politics over the last three centuries - neglected by many papers published in the current discussion. Due to its location at the entrance to the main harbour on the Baltic Sea entrance, Wester-platte-Peninsula is cartographically the best-documented part of the delta of the Vistula river. The authors obtained the historical sources for this paper from seven archives, mainly from Po-land and Germany. That in-depth archival research allows the reconstruction of the spatial his-tory of Westerplatte based on a comprehensive archival survey and the digital and cartograph-ical analysis of 207 maps that originated between the 17th and 20th centuries. The results allow the authors to present the complex process of the place's environmental, urban and military transformations of the landscape that played an important role in European history. Studies presented in this article might form the basis for establishing new policy of preserving the cul-tural landscape. Such a tool may allow us to keep a balance between fluctuations of the current historical politics and more universal (solid) requirements for the protection of tangible and in-tangible heritage.

  • White light thermoplasmonic activated gold nanorod arrays enable the photo-thermal disinfection of medical tools from bacterial contamination
    • Federica Zaccagnini
    • Piotr Radomski
    • Maria Laura Sforza
    • Paweł Ziółkowski
    • Seok-In Lim
    • Kwang-un Jeong
    • Dariusz Mikielewicz
    • Nicholas P. Godman
    • Dean R. Evans
    • Jonathan E. Slagle
    • Michael E. Mcconney
    • Daniela De Biase
    • Francesca Petronella
    • Luciano de Sio
    2023 Full text Journal of Materials Chemistry B

    The outspread of bacterial pathogens causing severe infections and spreading rapidly, especially among hospitalized patients, is worrying and represents a global public health issue. Current disinfection techniques are becoming insufficient to counteract the spread of these pathogens because they carry multiple antibiotic-resistance genes. For this reason, a constant need exists for new technological solutions that rely on physical methods rather than chemicals. Nanotechnology support provides novel and unexplored opportunities to boost groundbreaking, next-gen solutions. With the help of plasmonicassisted nanomaterials, we present and discuss our findings in innovative bacterial disinfection techniques. Gold nanorods (AuNRs) immobilized on rigid substrates are utilized as efficient white lightto-heat transducers (thermoplasmonic effect) for photo-thermal (PT) disinfection. The resulting AuNRs array shows a high sensitivity change in refractive index and an extraordinary capability in converting white light to heat, producing a temperature change greater than 50 1C in a few minute interval illumination time. Results were validated using a theoretical approach based on a diffusive heat transfer model. Experiments performed with a strain of Escherichia coli as a model microorganism confirm the excellent capability of the AuNRs array to reduce the bacteria viability upon white light illumination. Conversely, the E. coli cells remain viable without white light illumination, which also confirms the lack of intrinsic toxicity of the AuNRs array. The PT transduction capability of the AuNRs array is utilized to produce white light heating of medical tools used during surgical treatments, generating a temperature increase that can be controlled and is suitable for disinfection. Our findings are pioneering a new opportunity for healthcare facilities since the reported methodology allows non-hazardous disinfection of medical devices by simply employing a conventional white light lamp.

  • Whither the need and motivation for open government data (OGD) promotional strategies?
    • Charalampos Harris Alexopoulos
    • Stuti Saxena
    • Marijn Janssen
    • Nina Rizun
    2023 Full text Digital Policy Regulation and Governance

    Purpose It has been underscored in the extant literature that open government data (OGD) has not percolated across the length and breadth of any country, let alone the awareness of the OGD among the stakeholders themselves. In this vein, this study aims to underline the reasons as to why OGD promotion merits consideration apart from underlining the manner in which OGD promotion may be done. Design/methodology/approach Based on literature review on the OGD conceptual models and government promotion initiatives, the study further sketches an OGD model across four quadrants: beginners, followers, fast-trackers, trend-setters on the basis of the progress made in their OGD initiatives besides underlining the four elements of OGD promotional strategy as media, arena, substance and stakeholders. Also, the study explores the drivers and barriers to OGD promotional initiatives. Findings The study shows that across the OGD quadrants, the promotional strategies vary in terms of the 4As (acceptability, affordability, accessibility and awareness), and the same get reflected across MASS. Further, the drivers for OGD promotional initiatives are building citizens’ trust and forging stakeholder participation and collaboration in administration, thereby furthering transparency in administration, meeting the needs of the stakeholders, providing the desired impetus to value creation and innovation by the stakeholders and the need for furthering economic growth. Likewise, the barriers toward OGD promotion are linked with the lack of political will, lack of organizational leadership, mission and vision, lack of involvement of government departments, lack of budget and lack of requisite infrastructure for promotion. Originality/value Hitherto, OGD research has underscored the need to make the users aware of the potential of OGD initiative; however, no study has been undertaken to understand the manner in which the awareness may be driven among the users – the present study is a first step in this direction.

  • Whole-genome sequencing and antimicrobial potential of bacteria isolated from Polish honey
    • Ahmer Hafeez
    • Karolina Pełka
    • Kamila Buzun
    • Randy Worobo
    • Piotr Szweda
    2023 Full text APPLIED MICROBIOLOGY AND BIOTECHNOLOGY

    The aim of this study was the whole-genome analysis and assessment of the antimicrobial potential of bacterial isolates from honey harvested in one geographical location—the north of Poland. In total, 132 strains were derived from three honey samples, and the antimicrobial activity of CFAM (cell-free after-culture medium) was used as a criterion for strain selection and detailed genomic investigation. Two of the tested isolates (SZA14 and SZA16) were classified as Bacillus paralicheniformis, and one isolate (SZB3) as Bacillus subtilis based on their ANI and phylogenetic analysis relatedness. The isolates SZA14 and SZA16 were harvested from the same honey sample with a nucleotide identity of 98.96%. All three isolates have been found to be potential producers of different antimicrobial compounds. The secondary metabolite genome mining pipeline (antiSMASH) identified 14 gene cluster coding for non-ribosomal peptide synthetases (NRPs), polyketide synthases (PKSs), and ribosomally synthesized and post-translationally modified peptides (RiPPs) that are potential sources of novel antibacterials. The BAGEL4 analysis revealed the presence of nine putative gene clusters of interest in the isolates SZA14 and SZA16 (including the presence of six similar clusters present in both isolates, coding for the production of enterocin Nkr-5-3B, haloduracin-alpha, sonorensin, bottromycin, comX2, and lasso peptide), and four in B. subtilis isolate SZB3 (competence factor, sporulation-killing factor, subtilosin A, and sactipeptides). The outcomes of this study confirm that honey-derived Bacillus spp. strains can be considered potential producers of a broad spectrum of antimicrobial agents.

  • Why is TASK Quarterly a Significant Journal to Publish Your Article? —A Bibliometric Analysis of a Scientific and Technical Journal
    • Beata Adamczak
    2023 Full text TASK Quarterly

    A bibliometric analysis of TASK Quarterly in the years 1997-2021 in terms of various bibliometric indicators was performed to celebrate the 25th anniversary of the publication of the first issue of the journal. The number of publications and citations increased over the mentioned span of years. The leading countries in terms of the greatest number of papers published in TASK Quarterly are Poland, Italy, Germany, Ukraine, USA and Russia. Moreover, it is shown that international collaboration can result in a greater number of citations per publication. The average publication time in TASK Quarterly is 77 days, including the average submission-acceptance time (44 days) and the average acceptance publication time (33 days). Based on the author’s findings, it can be seen that although TASK Quarterly is a journal devoted mainly to physical and computer sciences, many publications also focus on the aspects related to mathematics, biomedical engineering and biophysics. CFD, molecular dynamics, the finite element method (FEM) and numerical simulations are the most frequently used keywords in articles published in TASK Quarterly.

  • Will NILM Technology Replace Multi-Meter Telemetry Systems for Monitoring Electricity Consumption?
    • Bartłomiej Gawin
    • Robert Małkowski
    • Robert Rink
    2023 Full text ENERGIES

    The estimation of electric power utilization, its baseload, and its heating, light, ventilation, and air-conditioning (HVAC) power component, which represents a very large portion of electricity usage in commercial facilities, are important for energy consumption controls and planning. Non-intrusive load monitoring (NILM) is the analytical method used to monitor the energy and disaggregate total electrical usage into appliance-related signals as an alternative to installing multiple electricity meters in the building. However, despite considerable progress, there are a limited number of tools dedicated to the problem of reliable and complete energy disaggregation. This paper presents an experiment consisting in designing an electrical system with electrical energy receivers, and then starting NILM disaggregation using machine learning algorithms (MLA). The quality of this disaggregation was assessed using dedicated indicators. Subsequently, the quality of these MLA was also verified using the available BLUED data source. The results show that the proposed method guarantees non-intrusive load disaggregation but still requires further research and testing. Measurement data have been published as open research data and listed in the literature section repository.

  • Winding function approach based design of novel five-phase brushless doubly fed induction generator
    • Roland Ryndzionek
    • Krzysztof Blecharz
    • Filip Kutt
    • Grzegorz Kostro
    • Michał Michna
    • Marcin Morawiec
    2023

    The paper presents the concept of the new design of the five-phase brushless doubly fed induction generator. The generator is dedicated to the modern wind turbine. The innovative design approach uses a five-phase power supply from the stator control winding side of the generator with a stator three-phase classic power winding. The research results presented indicate that the electromagnetic coupling between the control and power windings of a brushless, doubly fed induction generator can be avoided. The five phase control winding allows for more flexible machine control and also opens new possible configurations in terms of winding distribution and core designs for the brushless doubly fed generators.

  • Wireless Body Area Network for Preventing Self-Inoculation Transmission of Respiratory Viral Diseases
    • Łukasz Pawlicki
    • Alicja Fotyga
    • Jakub Rewieński
    • Mateusz Groth
    • Łukasz Kulas
    • Grzegorz Fotyga
    2023 Full text SENSORS

    This paper proposes an idea of Wireless Body Area Networks (WBANs) based on Bluetooth Low-Energy (BLE) standards to recognize and alarm a gesture of touching the face, and in effect, to prevent self-inoculation of respiratory viral diseases, such as COVID-19 or influenza A, B, or C. The proposed network comprises wireless modules placed in bracelets and a necklace. It relies on the received signal strength indicator (RSSI) measurements between the bracelet and necklace modules. The measured signal is cleared of noise using the exponential moving average (EMA). Next, we use a classification algorithm based on a Least-Squares Support Vector Machine (LSSVM) in order to detect facial touches. When the results of the classification indicate that the hand is moving toward the face, an alarm is sent through the neck module and the vibrator embedded in the wrist module is switched on. Based on the performed tests, it can be concluded that the proposed solution is characterized by high accuracy and reliability. It should be useful, especially for individuals who are regularly exposed to the risk of respiratory infections

  • Wireless Link Selection Methods for Maritime Communication Access Networks—A Deep Learning Approach
    • Michał Hoeft
    • Krzysztof Gierłowski
    • Józef Woźniak
    2023 Full text SENSORS

    In recent years, we have been witnessing a growing interest in the subject of communication at sea. One of the promising solutions to enable widespread access to data transmission capabilities in coastal waters is the possibility of employing an on-shore wireless access infrastructure. However, such an infrastructure is a heterogeneous one, managed by many independent operators and utilizing a number of different communication technologies. If a moving sea vessel is to maintain a reliable communication within such a system, it needs to employ a set of network mechanisms dedicated for this purpose. In this paper, we provide a short overview of such requirements and overall characteristics of maritime communication, but our main focus is on the link selection procedure—an element of critical importance for the process of changing the device/system which the mobile vessel uses to retain communication with on-shore networks. The paper presents the concept of employing deep neural networks for the purpose of link selection. The proposed methods have been verified using propagation models dedicated to realistically represent the environment of maritime communications and compared to a number of currently popular solutions. The results of evaluation indicate a significant gain in both accuracy of predictions and reduction of the amount of test traffic which needs to be generated for measurements.

  • Władza misjonarzy. Zmierzch i świt świeckiej religii w Dolinie Krzemowej
    • Jan Kreft
    2023

    "Władza misjonarzy" to książka o misjonarskim zapale zmieniania świata i o kryzysie świeckiej religii towarzyszącej liderom nowych technologii, o ich świętokradztwach i sprofesjonalizowanej pokucie mającej przywrócić harmonię technologicznego raju na ziemi z Alphabetem, Metą, Apple i TikTokiem w roli głównej. Także o skruszonych inżynierach, żałujących każdej chwili, którą poświęcili na wymyślanie uzależniających algorytmicznych rozwiązań na naszych smartfonach i komputerach. Gdy technologia, rynek i konkurencja stawały się religią, szefowie firm nowych technologii i mediów zostawali misjonarzami Nowego Technooświecenia. Facebook (Meta) i Google (Alphabet) – organizacje o silnych kosmologiach – „emanowały boskością” i instrumentalnie wykorzystywały „święte” wartości, takie jak sprawiedliwość. Współczesne etyczne katastrofy Big Tech i „zmierzch technobogów” oznaczają kryzys legitymizowania przez świecką religię ich niewinności, sprawczości i bezkarności. Zanika wiara w ich dobre intencje i neoliberalną sakralizację rynku. Upada imperatyw „policzalności wszystkiego”, dostrzegana jest fasadowość języka świeckiej religii i ujawniane są „fałszywe metafory”. Na horyzoncie widać jednak świt nowego technouniwersum. Na gruzach „świętego przymierza” między użytkownikiem a Big Tech rodzą się nowe wizje i mity. Już nie „naprawy świata”, ale „poprawy” człowieka, a czasem jego zastępowania, jak w wypadku „generatywnej sztucznej inteligencji”

  • Właściwości katalityczne i biomedyczne związków zawierających jony rutenu(II) oraz rutenu(III)
    • Kacper Pobłocki
    • Marta Pawlak
    • Juliusz Walczak
    • Joanna Drzeżdżon
    • Dagmara Jacewicz
    2023 Full text Wiadomości Chemiczne

    Ruthenium complexes appear in scientific publications mainly as catalysts in the olefins metathesis process. In this review, we want to indicate the research niche regarding the use of ruthenium(II) and ruthenium(III) complexes in other catalytic processes, i.e. polymerization or epoxidation of olefins and depolymerization. We would like to combine the catalytic properties of ruthenium(II,III) complex compounds with their biomedical activity due to the growing problem of drug resistance (including antibiotic resistance). Scientists have been designing new metallopharmaceuticals exhibiting biological activity for several years, therefore this requires a critical review of the literature. The main goal of designing new metallodrugs is to create compounds with new or stronger biological properties compared to free ligands. Ruthenium compounds are considered potential substitutes for known drugs. In particular, Ru(II) and Ru(III) based complexes have reduced toxicity and can be tolerated in vivo. In addition, a wide spectrum of ruthenium oxidation states, a different mechanism of action and the kinetics of ligand substitution increase the advantage over coordination complex compounds based on platinum. In conclusion, in this review, we will focus on the latest reports from the literature on the catalytic properties and biomedical activity of ruthenium(II) and ruthenium(III) chemical compounds.

  • Wodór czynnikiem stabilizującym odnawialne źródła energii
    • Witold Lewandowski
    2023

    Zastosowanie wodoru do magazynowania i buforowania energii ze źródeł odnawialnych, o cyklicznie i losowo zmiennym natężeniu, pozwoli korzystać z niej w zaplanowany i przewidywalny sposób. Wymagać to będzie takiego opracowania systemu energetycznego kraju, aby po jego zbilansowaniu nadwyżka energii zmagazynowanej w wodorze wystarczyła do wyrównania jej wahań: dobowych (energia słoneczna), atmosferycznych (wiatrowa), sezonowych (biomasa, biogaz, odpady) i innych z pozostałych odnawialnych źródeł. Przewymiarowana, w stosunku do potrzeb chwilowych, moc pozyskiwana z tych urządzeń powinna zapewnić niezbędną ilość energii zarówno na potrzeby bieżące, jak i do zapewnienia odpowiedniej ilości wodoru niwelującego wahania w mocy sieci. Energia chemiczna zmagazynowana w wodorze,, przechowywanym w specjalnie zaprojektowanych podziemnych zbiornikach, może być przetworzona, może natomiast być przetworzona w zależności od potrzeb w szczytowych kotłach parowych, turbinach gazowych, ogniwach paliwowych, – w zależności od potrzeb, w energię elektryczną i cieplną oraz na bieżąco w energię mechaniczną w środkach transportu drogowego, kolejowego, lotniczego lub morskiego.

  • Working Conditions in the Context of Global Value Chains and Routinisation: An Example of Polish Workers
    • Dagmara Nikulin
    • Joanna Wolszczak-Derlacz
    2023 Full text Gospodarka Narodowa

    The paper aims to explore the linkages between global production fragmentation, routinisation and the well-being of workers in Poland. In particular, the focus is placed on the selected measures of working conditions, such as the social environment, work intensity, and working time quality to examine their dependence on involvement in international trade and the routinisation level. We merge individual data describing the working conditions and well-being of workers with sector-level data containing information on involvement in global production processes and occupational data on the job routinisation level. The findings reveal a moderate association between working conditions and global value chain (GVC) involvement among Polish workers. In more GVC-dependent sectors, workers receive lower remuneration on average. The relationship between GVC and other working conditions is significant, but the economic significance is marginal. Similarly, the routinisation of work is negatively correlated with wages and working conditions (except work intensity). The main contribution of this study is its multidimensional approach to analysing working conditions, which significantly expands existing evidence in the literature.

  • Wpływ generacji rozproszonej na system elektroenergetyczny
    • Zbigniew Lubośny
    2023

    Monografia zawiera referaty zaprezentowane podczas XX Jubileuszowej Konferencji Naukowej Aktualne Problemy w Elektroenergetyce – APE’23, która odbyła się na Politechnice Gdańskiej w dn. 21–22 czerwca 2023 r. Celem Konferencji było przedstawienie aktualnych problemów elektroenergetyki, kreowanie jej perspektyw rozwojowych oraz umożliwienie nawiązania współpracy środowiska naukowego i przemysłu. Wśród poruszanych zagadnień znalazły się kwestie sterowania praca systemu elektroenergetycznego, regulacji napięcia w systemie elektroenergetycznym, wpływu generacji rozproszonej na system elektroenergetyczny oraz jego bezpieczeństwa pracy.

  • Wpływ grubości kryzy cylindrycznej na stabilność współczynnika przepływu przy niskich wartościach liczby Reynoldsa
    • Andrzej Mrowiec
    • Anna Golijanek-Jędrzejczyk
    2023

    W pracy przedstawiono wyniki badań eksperymentalnych i numerycznych dla kryzy cylindrycznej o przewężeniu β = 0,5 przy przepływającej wodzie w kanale DN50. Analizie poddano trzy kryzy cylindryczne dla wybranych wartości stosunku długości (grubości) otworu przepływowego do jego średnicy L/d (0,5; 1,0 i 2,0). Eksperymenty przeprowadzono w zakresie zmiany liczb Reynoldsa 1800 < Re < 17000, a symulacje numeryczne dla wybranego punktu określonego wartością strumieniem objętości qv = 0,55 dm3/s. Zrealizowane dotychczas badania doświadczalne nie pozwalają na przedstawienie najkorzystniejszej bezwymiarowej zależności długości otworu kryzy (L/d). Pozwalają jednak stwierdzić że w przebadanym zakresie liczby Reynoldsa dla L/d = 1,0 i L/d = 2,0 wartość współczynnika przepływu stabilizuje się i osiąga wartość C ˃ 0,8. Co jest zgodne z rozważaniami teoretycznymi i badaniami eksperymentalnymi, które przeprowadzono przy przepływie gazu przez długie otwory o małych średnicach (grube kryzy) [11]. Jednak najważniejszą zaletą tego typu kryz w porównaniu do innych jest możliwość wykonywania pomiarów w obu kierunkach przepływu, przy prawidłowym ich wykonaniu (ze względu na ostre krawędzie), dzięki czemu mogą być one wykorzystywane już dla przepływów laminarnych, gdzie nie radzą sobie znane znormalizowane kryzy centryczne.