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1

Symulacje CFD w przemyśle petrochemicznym

Gałęziowska Karolina, Grzywacz Robert, Michorczyk Piotr

Przemysł Chemiczny

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2025

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T. 104, nr 11

1185--1191

PL

Dokonano krótkiego przeglądu metod modelowania CFD w przemyśle petrochemicznym. Scharakteryzowano wybrane modele oraz wskazano przykłady ich zastosowania. Poruszono problemy i wskazano możliwe kierunki rozwoju.

EN

A review, with 23 refs., of pract. CFD modeling methods. In particular, models of multiphase flow, heat exchange, mixing, sorption, combustion and reaction kinetics were presented. Some issues and potential future development directions were discussed.

2

Numerical study of the effect of river-sea ship hull form parameters on resistance and their optimisation using the Taguchi-grey method

Tu Tran Ngoc, Le Tat Hien, Thien Doan Minh, Tao Tran Van, Ngoc Vu Minh

Polish Maritime Research

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2025

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nr 2

17--28

EN

In this paper, we systematically investigate the effect of the five most important ship hull form parameters, namely the longitudinal centre of buoyancy (LCB), the half angle of entrance of the design waterline ((½))αE), and the length (CLPR), cross-section (CABT) and volume (C ΔPR) parameters for the bulbous bow on the ship resistance using a computational fluid dynamics method. The parent ship hull form investigated in this study is a 4600DWT cargo ship, which operates on Vietnam’s river-sea routes. To save time and reduce costs, only 25 test cases designed with the orthogonal array Taguchi method are simulated, and the resistance is calculated in deep and shallow water at speeds of 10.0 and 9.0 knots, respectively. The optimal combination of the five ship hull form parameters is obtained using Taguchi-grey relational analysis. The results indicate that the optimum ship hull form depends on the water depth, and that LCB is the most critical parameter in regard to resistance. Of the combinations studied here, the variant with (½)αE=42°, CLPR=0.0141, CABT=0.1600, C ΔPR=0.00173, LCB=48.654%LBP is found to be optimal.

3

Drag Reduction and EEXI Compliance: Evaluating Air Lubrication for In-Service Ships via CFD

Abbas Nawar, Hawa Rami, Hatem Wehad

Polish Maritime Research

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2025

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nr 4

59--77

EN

This research used CFD techniques to study the effect of air lubrication technology on the Energy Efficiency Existing Ship Index (EEXI), developed by the International Maritime Organization. The Unsteady RANS (Reynolds-Averaged Navier-Stokes Equation) and the k-ω SST turbulence model were used to solve the Navier-Stokes equations governing flows, while the Volume of Fluid (VOF) method was used to solve the two-phase (air-water) flow. The JBC bulk carrier was chosen for this study because its shape closely resembles that of bulk carriers and tankers currently operating in the merchant fleet. Initially, the ship model was studied alone, without any appendages, at a scale of 1:40. The MP687 propeller was used with this ship in a self-propulsion test. An Open Water Test was conducted, with the Verification and Validation procedure being applied to the CFD results obtained for the JBC alone, in order to verify the accuracy of the numerical grid and the equations and turbulence models used to complete these calculations. The wave effect and ship motions (pitch, heave, roll, etc.) were neglected and the calculations were carried out in calm water. Then, air flow directing strakes were added to the bottom of the parallel body of the ship to investigate the impact of air lubrication on the EEXI value. At this stage, air lubrication was used for the ship alone, without a propeller, and then again for the ship with a propeller. Several types of air flow-directing strakes were tested, to trap air beneath the parallel body of the hull. The implementation of air lubrication technology with the proposed strakes reduced total ship resistance, resulting in a 16.67% improvement in the attained EEXI value. This reduction directly correlates with lower CO₂ emissions per unit of transport work (measured in grams of CO₂ per ton × nautical mile), demonstrating the system’s potential to enhance compliance with IMO’s carbon intensity regulations, without compromising operational performance.

4

Computational evaluation of the limiting thrust of the peripheral thruster taking into account the propeller blade yield stress and the thrust breakdown due to cavitation

Kraskowski Marek, Dymarski Paweł, Dymarski Czesław, Hebel Włodzimierz, Łuniewski Paweł

Polish Maritime Research

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2025

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nr 2

106--114

EN

The work presented in this article is related to the performance of an alternative design for the side thruster for ships, referred to as a peripheral thruster. Unlike the standard side thruster design, which uses the tunnel across the hull structure, the peripheral thruster consists of two separate devices mounted on two sides of the hull, with retracTable ducted propellers. The computational analyses presented here focus on evaluation of the maximum thrust achievable by this alternative design for the side thruster for a specified propeller diameter of 250 mm. Two limiting factors were considered: the strength of the propeller material, and the drop in thrust due to excessive cavitation. The analyses were carried out using STAR-CCM+ solver, and involved both a flow model (RANS FVM) and a solid stress model (FEM). The article focuses on the sensitivity of the results to the settings of the computational models, which is a key issue for this type of analysis due to its complexity.

5

Obliczenia cieplne maszyn elektrycznych chłodzonych olejem

Będkowski Bartłomiej

Napędy i Sterowanie

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2025

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R. 27, nr 7/8

74--77

PL

W pracy przedstawiono przykładowe konstrukcje maszyn elektrycznych z chłodzeniem olejowym. Ponadto przeanalizowano możliwości obliczeń cieplnych maszyn z bezpośrednim chłodzeniem olejowym, wraz z opisem budowy przykładowego uproszczonego modelu obliczeniowego. Omówione w publikacji modele opracowano w ramach realizacji projektu pt. „Innowacyjny elektryczny zespół napędowy do pojazdów użytkowych finansowanego przez NCBiR z programu LIDER XI nr umowy LIDER/15/0060/L-11/19/NCBR/2020.

EN

An examples of electric machine constructions with oil cooling were presented in the work. Furthermore, the possibilities of thermal calculations for machines with direct oil cooling were analyzed, along with a description of the construction of a simplified computational model. The models discussed in the publication were developed as part of the project titled “Innovative Electric Drive System for Utility Vehicles” funded by NCBiR under the LIDER XI program, contract number LIDER/15/0060/L-11/19/NCBR/2020.

6

The impact of the computational domain discretization method on the results of flow simulations around the naca 0012 airfoil profile

Misiak Aneta, Majcher Maciej

Journal of KONBiN

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2025

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Vol. 55, iss.3

137--177

EN

This article analyzes the impact of the method of computational domain discretization on the results of flow simulations around the NACA 0012 airfoil profile. For this purpose, a set of structural and hybrid meshes differing in the number of elements and the value of the 𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 𝑦𝑦+ parameter were constructed, based on which the profile flow simulations were performed. Numerical studies were carried out using ANSYS FLUENT software and consisted in determining the aerodynamic coefficients of the NACA 0012 profile and comparing their values with experimental data. The analyses carried out made it possible to determine the impact of the type of mesh and its main parameters on the reliability of the numerically obtained results.

PL

W niniejszym artykule przeprowadzono analizę wpływu sposobu dyskretyzacji domeny obliczeniowej na wyniki symulacji opływu wokół profilu lotniczego NACA 0012. W tym celu zbudowano zestaw siatek strukturalnych i hybrydowych różniących się między sobą liczbą elementów oraz wartością parametru 𝑐𝑐, w oparciu o które realizowano symulacje opływu profilu. Badania numeryczne zostały przeprowadzone z wykorzystaniem oprogramowania ANSYS FLUENT i polegały na wyznaczaniu współczynników aerodynamicznych profilu NACA 0012 i porównaniu ich wartości z danymi doświadczalnymi. Przeprowadzone analizy pozwoliły na ustalenie wpływu rodzaju siatki i jej głównych parametrów na wiarygodność uzyskiwanych numerycznie wyników.

7

Design and structural analysis of an innovative grain dryer frame with integrated mass measurement

Łykowski Wiktor, Gierz Łukasz, Berdychowski Maciej, Modrzejewska-Sikorska Anna, Javorova Juliana

Journal of KONBiN

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2025

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Vol. 55, iss.1

17--27

EN

Seeds of crops such as rapeseed, corn, and sunflowers require post-harvest drying for proper storage. Inadequate seed moisture leads to the development of bacteria and fungi. Excessively high seed moisture content promotes the growth of microorganisms, including bacteria and fungi, while excessively low moisture content reduces seed viability. The average moisture content of corn during harvest is up to 35%, in the case of rapeseed, 12%, and in the case of wheat – 18%, while the recommended moisture content for grain storage is 14% for corn, 6% for rapeseed, and 14% for wheat. Mobile and stationary dryers are available on the market and can be used as flow or batch dryers. The work aims to develop an innovative concept of a dryer with strain gauge measurement of the mass of dried material and to analyze the strength of its main frame. The dryers available on the market do not have scales that could control weight loss. The project included the analysis of commercialized and available solutions on the market, the development of a 3D CAD model of the entire dryer with a hopper of 8 m3, and an analysis of the strength of the dryer's main frame using the finite element method. SolidWorks was utilized for 3D modeling and the subsequent FEM strength analysis. The results of the FEM analysis demonstrate the structural integrity of the dryer, suggesting its feasibility for commercial production.

PL

Nasiona roślin uprawnych, takich jak rzepak, kukurydza i słonecznik, wymagają suszenia po zbiorach w celu właściwego przechowywania. Niewystarczająca wilgotność nasion prowadzi do rozwoju bakterii i grzybów. Z kolei nadmierna wilgotność zwiększa zawartość szkodliwych mikrotoksyn fuzaryjnych. Średnia wilgotność kukurydzy podczas zbioru wynosi do 35%, w przypadku rzepaku 12%, a pszenicy 18%, podczas gdy zalecana wilgotność do przechowywania ziarna wynosi 14% dla kukurydzy, 6% dla rzepaku i 14% dla pszenicy. Na rynku dostępne są suszarnie mobilne i stacjonarne, które mogą być wykorzystywane jako suszarnie przepływowe lub porcjowe. Celem pracy jest opracowanie innowacyjnej koncepcji suszarni z pomiarem masy suszonego materiału za pomocą tensometru oraz analiza wytrzymałości jej głównej ramy. Dostępne na rynku suszarnie nie posiadają wag umożliwiających kontrolę ubytku masy. W ramach projektu przeanalizowano dostępne i skomercjalizowane rozwiązania, opracowano model 3D CAD całej suszarni z zasobnikiem o pojemności 8 m³ oraz przeprowadzono analizę wytrzymałości głównej ramy suszarni metodą elementów skończonych. Model 3D i analiza wytrzymałościowa zostały wykonane w programie SolidWorks. Opracowana suszarnia ma dużą szansę na komercjalizację. Wyniki analizy elementów skończonych wykazują integralność strukturalną suszarki, co sugeruje, że może być komercyjnie produkowana.

8

Mechaniczne mieszanie w procesach technologicznych – eksperymentalna weryfikacja prototypowania kształtu wirnika

Młynarczykowska Anna

Inżynieria Mineralna

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2025

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Vol. 1, no. 1

177--182

PL

Mieszanie mechaniczne jest powszechnym procesem w systemach technologicznych w wielu gałęziach przemysłu. Jest to kluczowa operacja w wielu systemach inżynieryjnych, obejmująca reakcje chemiczne, dyspersję gazów w cieczach, tworzenie zawiesin i mieszanin oraz zapobieganie agregacji osadów. Ten pozornie prosty proces zależy od właściwości fizycznych i chemicznych mieszanych substancji, geometrii zbiornika i wirnika oraz warunków hydrodynamicznych generowanych podczas pracy mieszadła. Niniejszy artykuł przedstawia przykładowe wyniki badań opracowanej metodyki, która umożliwia prototypowanie mieszadeł, a w szczególności kształtu wirnika. Opiera się ona na obliczeniach numerycznych (CFD – Calculated Fluid Dynamics) i symulacji komputerowej z wykorzystaniem pakietu ANSYS Fluent, analizie rozkładu wektorów prędkości (metoda PIV – Particle Image Velocity) oraz wyznaczeniu wskaźników kryterialnych charakteryzujących przepływ, takich jak wskaźnik mocy (Np), wskaźnik pompowania (Kc) i sprawność mieszania (E).

EN

Mechanical mixing is a common process in technological systems across many industries. It is a key operation in a large number of engineering systems, including chemical reactions, gas dispersion in liquids, the formation of suspensions and mixtures, and the prevention of sediment aggregation. This seemingly simple process depends on the physical and chemical properties of the substances being mixed, the geometry of the tank and impeller, and the hydrodynamic conditions generated during mixer operation. This paper presents examples of research results for the developed methodology, which enables the prototyping of mixers, particularly the impeller shape. It is based on numerical calculations (CFD – Calculated Fluid Dynamics) and computer simulation using the ANSYS Fluent package, analysis of velocity vector distribution (PIV – Particle Image Velocity method), and the determination of criteria numbers characterizing flow, such as the power number (Np ), the pumping number (Kc ), and the mixing efficiency (E).

9

Prediction of degradation in 90° elbow joints of ba35 brass used in potable water pipes through computational fluid dynamics (CFD) simulation

Bennis H. T., Zniker H., El Kouifat M. K., Bennajah M., Ouaki B.

International Journal of Applied Mechanics and Engineering

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2025

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Vol. 30, no. 2

46--61

EN

Failure of 90° elbows in water pipes due to corrosion is a critical issue in water supply and distribution systems. Therefore, understanding the behavior of pipelines under corrosion is essential to increase their durability. This original study aims to specifically analyze the failure of 90° elbows due to the erosion-corrosion phenomenon. The behavior of water flow, in terms of velocity profile, pressure gradient, and turbulence zones at these elbows, is numerically simulated using the computational fluid dynamics (CFD) method. The simulations, performed with FLUENT software, identify the areas most susceptible to erosion and corrosion, thus contributing to a better understanding of processes such as stress corrosion cracking and cavitation. This work also highlights the importance of designing elbows with suitable characteristics and adopting adequate maintenance practices to prevent failures. These results can serve as a basis for future experimental validations and for the design of more robust pipeline systems.

10

Sprawność operacyjna jako miara skuteczności wentylacji naturalnej garażu otwartego

Miechówka Bartosz, Węgrzyński Wojciech, Jamińska-Gadomska Paulina, Krajewski Grzegorz

Instal

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2025

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nr 1

23--28

PL

Wykonano 192 symulacje CFD pożaru garażu otwartego w warunkach wiatrowych w celu oceny sprawności wentylacji naturalnej. W większości rozpatrywanych przypadków wentylacja naturalna była nieskuteczna. Zauważono wpływ kierunku wiatru na skuteczność działania wentylacji. Posiadając historyczne dane wiatrowe, oszacowano procent czasu, w którym wyniki są akceptowalne. Wartość tą nazwano sprawnością operacyjną systemu i wynosiła ona 87,62% dla mocy pożaru 1,4 MW; 40,30% dla 4,0 MW; 36,39% dla 6,0 MW i 14,24% dla 8,8 MW.

EN

192 CFD simulations of an open car park fire under wind conditions were conducted to assess the efficiency of natural ventilation. In the majority of considered cases, natural ventilation was ineffective. The influence of wind direction on ventilation performance was observed. Using historical wind data, the percentage of time during which the outcomes were acceptable was estimated. This value was termed operational uptime and amounted to 87.62% for a fire with a heat release rate of 1.4 MW; 40.30% for 4.0 MW; 36.39% for 6.0 MW; and 14.24% for 8.8 MW.

11

Development of a computational framework for low-Reynolds number propeller aeroacoustics

Szulc O., Suresh T., Flaszyński P.

Archives of Mechanics

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2025

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Vol. 77, nr 1

67--85

EN

The paper focuses on the development and validation of a new computational framework designed for the prediction of tonal and broadband noise radiation of propellers of unmanned aerial vehicles (UAVs) operating in the low-Reynolds number regime. The depictedworkflowis hybrid, consisting of in-house, academic, and commercial software components intended for automatic pre-processing (block-structured grid generation), efficient flow solution (computational fluid dynamics, CFD), and acoustic post-processing (computational aeroacoustics, CAA). The delayed detached-eddy simulation (DDES) approach constitutes the basis for estimation of mean blade loading and surface pressure fluctuations due to the existence of massive flow separation that are fed as input to an in-house acoustic solver based on Ffowcs Williams and Hawkings (FW–H) linear acoustic analogy (Farassat’s formulation 1A). The initial phase of validation of the acoustic tool is conducted for elementary rotating and oscillating point sources of mass and momentum (forces) using available analytical solutions for reference. Later, a two-bladed model propeller from the Delft University of Technology (TUD) is analyzed with FLOWer (compressible CFD solver from DLR), relying on RANS or DDES approaches and equipped with either 1-equation strain adaptive linear Spalart–Allmaras or 2-equation shear-stress transport k–! turbulence closures. The equations are solved using both classical second-order and modern fourth-order accurate numerical schemes. For a selected rotational speed of 5000 RPM (tip Mach number of 0.23 and tip Reynolds number of 50 • 103) and the range of the advance ratio J of the axial flight, the predicted propeller aerodynamic performance is confronted with the measurements of TUD. Lastly, for exemplary J = 0 (hover conditions, tripped boundary layer), the resolved pressure fluctuations (URANS/k–! SST and DDES/k–!SST) are directly used as input for acoustic analysis of tonal (harmonic) and broadband noise at an in-plane observer location and the resultant propeller sound pressure level signature is compared with the measured spectrum confirming the applicability of the developed framework for such computationally demanding cases of flow-induced noise.

12

Analysis of the basic aerodynamic characteristics of an unmanned combat aerial vehicle based on a CAD model

Szczepaniak Robert, Czyż Zbigniew, Bąbel Robert, Mańka Amadeusz, Zahorski Tomasz, Omen Łukasz, Kosicka Ewelina, Matijosius Jonas, Ngouobe Japhet Noubiap

Advances in Science and Technology. Research Journal

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2025

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Vol. 19, no. 6

235--247

EN

This paper presents an overview of selected unmanned aerial vehicle (UAV) designs to show the development of unmanned aircraft. In this context, the paper describes the application of CAD design in creating a 3D model in order to perform basic aerodynamic CFD simulations. The IAI Heron was selected for geometry modelling. Based on digital analyses of publicly available design materials and photographs, simplified models of the selected structure were created using the SolidWorks software. Basic aerodynamic characteristics of the developed geometric model of the AIA Heron were obtained by calculations made with ANSYS Fluent. The paper analyses the results obtained and compares them to data in the literature for a similar class of UAV. The prepared model will serve as a basis for future 3D prints. The developed CFD numerical model will be used for further comparative analysis and validation in wind tunnel tests.

13

Effect of mesh density and grid type on cavitation cloud volume

Jasionowski Robert, Kostrzewa Waldemar

Zeszyty Naukowe Politechniki Morskiej w Szczecinie

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2024

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nr 80 (152)

23--31

EN

This work is devoted to determining the effect of mesh density and mesh type on cavitation cloud volume generated during the flow of water through the cavitation tunnel. The numerical analysis was carried out on a water model based on a cavitation tunnel located at the Institute of Water Problems of the Bulgarian Academy of Sciences in Sofia, used to test the resistance of construction materials to cavitation erosion. A numerical analysis is performed for four different types of grids: polyhedra, poly-hexcore, hexcore, and tetrahedral. These grids have five different maximum cell sizes: 0.0025, 0.0020, 0.0015, 0.0010, and 0.0005 m. A numerical analysis is performed using commercial CFD software ‒ i.e., Ansys Fluent 2023 R1. The Schnerr and Sauer cavitation model and the k-omega viscous model for shear stress transport (SST) are used. This paper analyzes the qualitative parameters of the quality of the grid, distribution of velocity, pressure, average cell volume, and volume of cavitation cloud consisting of 90% volume vapor fraction. Based on the numerical analyses, it is shown that the basis for obtaining accurate results of the CFD simulations is not only the qualitative parameters of the grid but also its density.

14

The key role of modern aerodynamic trends in increasing the energy efficiency of high-speed vehicles

Shkvar Yevhenii, Kandume Jonas, Redchyts Dmytro

Transport Problems

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2024

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T. 19, z. 1

107--116

EN

Based on the analysis of typical operating modes of modern high-speed trains and transport aircraft, the influence of various schemes of surface relief modification and blowing through it on aerodynamic drag has been thoroughly investigated. A set of several schemes of the combined effect of these two factors is proposed to create an easy-to-use, cheap-to-produce streamlined surface of the desired structure with a reliable and controllable effect of active influence on aerodynamic drag reduction. The potential effect of reducing aerodynamic drag has been verified by numerical and Particle Image Velocimetry experimental modeling. The proposed technological innovations are encouraging and relevant; by reducing energy costs, they increase the commercial and environmental attractiveness of their implementation.

15

Comparison of pressure-loss evaluation fidelity in turbulent energy dissipation models of poppet check valves using computational fluid dynamics (CFD) software

Kobielski Maciej. J., Skarka Wojciech, Skarka Michał

Technical Sciences / University of Warmia and Mazury in Olsztyn

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2024

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Vol. 27

19--31

EN

Check valves are critical components of fluid systems and have various applications, including house appliances. This article presents a methodology for mapping geometry-specific constriction pressure loss as a function of flow and turbulence in a check valve. This study aimed to gain insight on which Ansys Fluent available turbulent energy dissipation model should be used for further design optimization. This methodology consists of a statistical comparison of computational fluid dynamics (CFD) simulation results obtained using the turbulent energy dissipation models. The key components of the simulation process are discussed. The study’s main results are a comparison of empirical results among flow models’ estimated pressure loss, shown as a function of flow rate in specific geometry and identification of the most suitable model for the considered application. This study concludes that the K-Epsilon (Standard) model best represents the empirically measured behavior of naturally occurring flow energy losses in the considered geometry.

16

Identyfikacja zjawisk przepływowych w rurze ssącej średniobieżnej turbiny wodnej z wykorzystaniem CFD

Nycz Aneta, Szulc Przemysław, Skrzypacz Janusz

Rynek Energii

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2024

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Nr 4

64--73

PL

Zjawiska przepływowe w reakcyjnych turbinach wodnych zależą od położenia punktu pracy. Ma to szczególne znaczenie dla elementu odprowadzenia cieczy (rury ssącej/krzywaka ssącego). Celem badań przedstawionych w publikacji była identyfikacja wpływu stopnia regulacji turbiny Francisa na zjawiska przepływowe w rurze ssącej. Artykuł zawiera omówienie zagadnień dotyczących rodzajów modeli turbulencji, ich właściwości i zastosowania do rozpoznawania zjawisk występujących w turbinach wodnych. Symulacje przeprowadzono dla pozaoptymalnego stanu pracy turbiny z wykorzystaniem wybranych, dwurównaniowych modeli turbulencji stosowanych w ANSYS Fluent. Model numeryczny został poddany walidacji względem nominalnych parametrów pracy maszyny. Przeprowadzono analizę ilościową i jakościową wyników modelowania przepływu w turbinie przy częściowym zregulowaniu, w celu ustalenia, który z nich, najlepiej odwzorowuje zjawiska zachodzące w badanym przypadku.

EN

Flow phenomena in reaction water turbines depend on the position of the operating point. This is of particular importance for the ﬂuid discharge component (draft tube/curved draft tube). The aim of the research presented in the publication was to identify the inﬂuence of the degree of control of the Francis turbine on the ﬂow phenomena in the draft tube. The paper includes a discussion of issues concerning the types of turbulence models, their properties and their application to the identiﬁcation of phenomena occurring in water turbines. Simulations were carried out for a non—optimal turbine operating condition using selected two—variable turbulence models applied in ANSYS Fluent. The numerical model was validated against nominal machine operating parameters. A quantitative and qualitative analysis was carried out and qualitative analysis of the modelling results of the turbine ﬂow at partial regulation was carried out in order to determine which model best represents the phenomena occurring in the case studied.

17

Uszkodzenia korozyjne wysokotemperaturowe w kolektorze rurowego wymiennika ciepła wynikające z niekorzystnych warunków przepływu i miejscowego przegrzania : analiza CFD

Parol Filip, Pawlicki Jakub

Przemysł Chemiczny

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2024

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T. 103, nr 12

1473--1478

PL

Przedstawiono wyniki analiz przepływowo-strukturalnych CFD kolektora wraz z początkowym odcinkiem rurek wymiennika ciepła konstrukcji ALSTOM. Analizy termiczno-przepływowe są częścią kompleksowych badań nad przyczynami uszkodzeń rurek wewnętrznych, spowodowanych szybko postępującą korozją od strony przestrzeni wodnej w okolicy połączenia z dnem sitowym. Przeprowadzono je na podstawie wcześniej wykonanych analiz materiałowych i procesowych. Badania materiałowe wykazały, że przyczyną uszkodzenia rur kotła była wysokotemperaturowa korozja w środowisku woda-para. Na podstawie analizy procesów technologicznych stwierdzono prawdopodobieństwo niewystarczającego odgazowania w deaeratorze oraz możliwe nagromadzenie osadów korozyjnych. Analizy termiczno-przepływowe wskazały na występowanie zastojów przepływu za częścią rurek wymiennika i pokrywanie się ich obszarów z typowymi miejscami uszkodzeń. Wykonano symulację uwzględniającą obecność warstwy korozyjnej na części powierzchni rurki i zaobserwowano znaczący wzrost temperatury w miejscach korozji.

EN

CFD flow-structural anal. of the manifold along with the initial section of the heat exchanger tubes, designed by ALSTOM were carried out to det. the causes of internal tube damage caused by rapidly progressing corrosion from the water side near the connection to the tube sheet. Flow-thermal anal. showed the occurrence of flow stagnation behind some of the heat exchanger tubes. Material tests showed that the cause of the boiler tube damage was high-temperature corrosion in a water-steam environment. A simulation was carried out taking into account the presence of a corrosion layer on part of the tube surface, revealing a significant increase in temp. in the corrosion areas.

18

Analiza numeryczna osiągów silnika rakietowego typu resistojet

Maleszyk Dawid, Kindracki Jan

Przemysł Chemiczny

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2024

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T. 103, nr 12

1527--1530

PL

Przedstawiono obliczenia numeryczne dotyczące silnika rakietowego typu resistojet. Silnik ten wyposażony jest w grzałkę elektryczną, która ogrzewa przepływający czynnik roboczy, dzięki czemu możliwe jest zwiększenie impulsu właściwego. Przedstawione analizy numeryczne silnika przeprowadzono dla różnych konfiguracji mocy grzałki oraz ciśnienia i rodzaju czynnika roboczego. Przedstawiono wizualizację przepływu oraz wymianę ciepła wewnątrz silnika, co stanowi istotną informację dla procesu optymalizacji pracy silnika, a także pozwala na wybór najlepszego czynnika roboczego.

EN

Numerical calcns. of a resistojet rocket thruster equipped with an electric heater that heats the flowing working medium were presented. Numerical analyses of the engine were performed for various configurations of heater power, pressure and type of working medium. Visualization of the flow and heat exchange inside the engine was presented, which provides important information for the engine optimization process and also allows the selection of the best working medium.

19

Ewolucja (reforma) unijnego rynku energii elektrycznej

Leśniak Artur, Palacz Karolina, Surma Tomasz, Zamasz Krzysztof

Przegląd Elektrotechniczny

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2024

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R. 100, nr 8

52--55

PL

Reforma rynku energii elektrycznej EMD ma za zadanie wprowadzić zmiany w zasadach funkcjonowania podmiotów na rynku energii elektrycznej w Unii Europejskiej, w celu ograniczenia zależności kosztów zakupu energii elektrycznej od cen paliw kopalnych i lepszej ochrony odbiorców energii przed dynamicznymi zmianami cen energii. Niniejszy artykuł stanowi analizę zaproponowanych przepisów, ze szczególnym zwróceniem uwagi na elementy istotne dla funkcjonowania polskich przedsiębiorstw energetycznych wraz z określeniem przewidywanego zakresu implementacji do polskiego porządku prawnego.

EN

The electricity market reform has been designed to change the rules of operation of the electricity market participants in the European Union in order to reduce the dependence of electricity costs on the prices of fossil fuels, and consequently – protect energy consumers from the volatility of energy prices. This article provides an analysis of proposed regulations, namely the key aspects of participation in the electricity market along with the expected scope of regulations to be implemented into Polish law.

20

Formation of methane hazards during underground coal production in the longwall area ventilated by System Y

Tutak Magdalena

Production Engineering Archives

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2024

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Vol. 30, Iss. 3

394--405

EN

The article addresses a critical and timely issue: improving safety in underground coal mining. The primary objective of the paper was to develop a research methodology based on modelling studies to identify and assess the state of methane hazards during mining operations. To achieve this, structural modelling of the physical and chemical phenomena occurring in mining regions was conducted using Computational Fluid Dynamics. The core research was performed using the finite volume method on a real longwall exploitation site ventilated by a Y-system. This approach enabled the determination of methane and oxygen concentration distributions in the mining region and goafs, treated as a porous and permeable medium. Based on these findings, potential fire and/or methane explosion hazard zones were identified in the goaf. The model test results underwent a validation process, comparing them with actual measurements. The determined errors were within an acceptable range, confirming the accuracy of the developed model of the mining region and the phenomena within it. Furthermore, the model was used to predict the locations of zones at risk of fire and/or methane explosion in the goafs, particularly in areas with potentially increased gas emissions. The results clearly demonstrate the significant potential of using model studies to diagnose and forecast methane hazards in underground mining operations. Identifying these potential danger zones allows for the implementation of preventive measures to reduce the likelihood of dangerous incidents.