Browsing by Subject "numerical simulations"

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Access status: Open Access ,
Aktualne możliwości komputerowej symulacji szczelinowania hydraulicznego w złożach
(2012) Wojnarowski, Paweł; Stopa, Jerzy
Celem pracy jest analiza aktualnych tendencji światowych w modelowaniu komputerowym zabiegów szczelinowania hydraulicznego a także ocena możliwości technicznych i przydatności wybranych symulatorów szczelinowania do projektowania zabiegów w różnych warunkach geologicznych, w tym dla złóż niekonwencjonalnych. W ramach pracy dokonano oceny przydatności oprogramowania GOHFER oraz Meyer Fracturing (MFrac i MShale) do prac projektowych zabiegu szczelinowania hydraulicznego, optymalizacji parametrów technologicznych oraz prognozowania produkcji. W tym celu wykonano testowe obliczenia symulacyjne z wykorzystaniem tych narzędzi.
Access status: Open Access ,
Analiza warunków stateczności tunelu w masywie skalnym o strukturze blokowej dla sytuacji tunelu metra w Nowym Jorku (rejon Manhattan)
(2007) Jakubowski, Jacek; Stypulkowski, Jacek
The paper presents discontinuities effect on tunnel stability conditions analyzed with MSB numerical simulation method. Based on statistical description of discontinuities network the MSB method and code creates representation of a blocky structure around a tunnel and analyzes it within a general statistical simulation scheme. Comprehensive description of geology in the vicinity of underground tunnel in Manhattan, New York was a basis for building a statistical model of discontinuities network followed by numerical simulation of stability conditions. Results for two different tunnel directions and for unsupported and rock bolted tunnel were compared. Information on observed geometry, location and size of real unstable blocks around the excavated tunnel allowed comparing computation results with observations.
Access status: Open Access ,
Analysis of applicability of flow-acoustic coupling used for pressure measurement
(Wydawnictwa AGH, 2023) Łojek, Paweł; Czajka, Ireneusz
This paper presents the concept and results of initial simulations of an acoustic system for absolute pressure measurement. Its working principle is based on a coupling between the flow and acoustic fields. The measurement is performed indirectly. The measurement of absolute pressure is based on measuring the velocity and time of arrival of an acoustic wave and the relationship between the pressure and speed of sound in a given medium. The concept was verified numerically using the finite volume method and the OpenFOAM environment. One possible application of the system is to measure the mean pressure on the walls of buildings.
Access status: Open Access ,
Law of development turbulent non-isothermal jet flow in pit oil
(Wydawnictwa AGH, 2012) Ajsaev, Satžan Uškanbaevič; Žapbasbaev, Uzak K.; Turegeldiyeva, Karlygash
This paper reviews development of turbulent non-isothermal round jet flow in pit oil. Increasing requirements for environmental protection challenge the oil industry to minimize the oil spill accidents throughout the production and transportation processes. Hydrodynamic interaction of pit oil with flow is in reasonable agreement with data of industrial tests. The authors prove law of development turbulent non-isothermal jet flow in pit oil. In this paper a mathematical model was designed and numerical simulation of turbulent non-isothermal flow in pit oil was performed. The mathematical method is based on the non-isothermal fluid flow in pit oil using solution of Reynolds-averaged Navier-Stokes equations and equations of the k-symbol model of turbulence. The developed model has been validated with experimental data. Numerical simulation calculation results were found to be in reasonable agreement with data obtained from the experiments. Turbulent (molar) transfer is important in flow part and vortex zone of reverse flow. In the other part convection and molecular mechanism of momentum and heat transfer dominated. The developed mathematical model and numerical simulation methods are used to study the process of heating pit oil by hot fluid flow. In technical aspect it allows to determine the mass of heated pit oil which is used in thermo-mechanical technology of gathering spilled oil.
Access status: Open Access ,
Nośności odrzwi wybranych obudów łukowych
(Wydawnictwa AGH, 2005) Hałat, Włodzimierz
Numerical simulation based on 66 models allowed a bearing capacity of the steel arch support to be estimated. It has been shown some results of calculations for three types of profiles: V21, V25 and V29 and three sizes of the support: ŁP8, ŁP9 and ŁP10. Each of the support model was induced - besides of active loading - with four passive loadings modeling strata influence upon the support. It has been found that complete use of bearing capacity of the arch support depends not only on value of bearing capacity of the arch, what is connected with yield limit of steel, but it also equally depends on bearing capacity of joints of the arches.
Access status: Open Access ,
Numerical analysis of the influence of the modification of the ladle shroud on fluid flow behavior in a one-strand tundish during continuous steel casting
(AGH University of Science and Technology Press, 2021) Suchan, Hanna; Cwudziński, Adam
A tundish is a device from which liquid steel is pour into a mold. Therefore tundish hydrodynamic conditions have a significant impact on solidification during continuous steel casting (CSC) process. Modification of ladle shroud workspace, allows for the modification of liquid steel movement in the tundish. In the following work, numerical simulations were performed which allowed the impact of the modification of the ladle shroud workspace on the liquid steel flow structure in a one-strand tundish to be determined. In order to assess the impact of the modification of the ladle shroud on the behavior of the liquid steel in the tundish, simulations were performed, on the basis of which the percentage share of stagnant, ideal mixing and plug flow zones were determined. In addition, the mixing parameters were determined, allowing the estimation of casting duration during sequential casting. The flow fields of liquid steel for each modification of the ladle shroud were performed. The average velocity of liquid steel flowing through the tundish, the Reynolds number and turbulent intensity were also described. The obtained results showed, among others, that the application of three cylinders with a diameter of 0.041 m into the ladle shroud with a diameter of 0.11 m increases the share of active flow in the tundish in relation to the tundish with Conventional Ladle Shroud. At the same time, applying a ladle shroud with a diameter of 0.11 m during casting is the most favorable in relation to the hydrodynamics of the tundish.
Access status: Open Access ,
Numerical and experimental investigations of the flow in the radial fan
(Wydawnictwa AGH, 2008) Fortuna, Stanisław; Sobczak, Krzysztof
The radial fan under investigation transfers energy in the form of mechanical work to the air. A three-dimensional flow structure in the rotor was determined on the basis of the computational and experimental data. A comparison of the numerical simulations by means of ANSYS CFX and thermoanemometer measurements of velocity as well as its components was presented. The results of numerical investigations, measurements and balance method were compared in order to determine the compressor performance characteristics.
Access status: Open Access ,
Numerical simulation on mining effects of upper coal seam on lower coal seam of splitting area of splitting and merging coal seam
(2012) Zha, Wen-hua; Hua, Xin-zhu; Xiong, Li-jun; Huang, Rong
Główne pokłady węglowe nr 71 i 72 kopalni Huaibei wykazują cechy zarówno rozszczepienia, jak i scalania. Podczas wybierania warstwowego na obszarze rozszczepienia głównym problemem jest zapewnienie bezpieczeństwa dolnego pokładu nr 72. Na przykładzie przodka 7225 kopalni Xutuan przeanalizowano wpływ wydobycia w pokładzie nr 71 na pokład nr 72 przy użyciu programu FLAC3D. Propagację fal naprężeń w spągu, zakres pęknięcia i przesunięcia podczas wybierania pokładu węgla nr 71 i 72 zbadano za pomocą symulacji numerycznej, co daje podstawy do lepszej kontroli stropu i do wyboru obudowy pod wybieranie pokładu węgla nr 72.
Access status: Open Access ,
Numeryczna symulacja wyburzenia komina murowego
(2008) Jakubowski, Jacek; Reiman, Krzysztof
Numerical simulation of 67,6 m high brick chimney felled by explosives is presented. Models have been build and computed with the use of Distinct Element Method and 3DEC-Itasca system. The results of the dynamic simulation, chimney basement stresses estimations and the process of chimney damage collapse agrees in general with experience and observations.
Access status: Open Access ,
Ocena efektywności stosowania wybranych metod wtórnych i trzecich eksploatacji ropy naftowej z wykorzystaniem symulacji komputerowej
(2010) Wojnarowski, Paweł; Pyrzak, Paweł
Effective exploitation of matured oil fields became important problem because of high oil demand. It is possible to increase recovery factor by application adequate secondary or EOR method of exploitation. In this work efficiency analysis of water flooding and polymer flooding for Carpathian oil field was done. Results of multivariant numerical simulations shows, that for selected heterogeneous reservoir polymer flooding is much efficient and could be used directly after primary recovery.
Access status: Open Access ,
Optimization of a gating system by means of simulation software to eliminate cold shut defects in casting
(AGH University of Science and Technology Press, 2021) Šabík, Vladimír; Futáš, Peter; Pribulová, Alena; Delimanová, Petra
The current trend in foundries is to achieve the production of high quality and competitive cast components. The innovation and optimization of current processes is a necessary element to achieve this goal. With the help of numerical simulations, it is possible to replace financially demanding and time-consuming experiments in real conditions with simulations that can reliably represent foundry process using computer technology. By a detailed analysis of the simulation results, we can predict various risks that could negatively affect the production process. This article monitors the influence of changes in the design of the gating system on the surface quality of a clutch wheel casting made of ductile iron, in the production of which two models of the gating system for casting were constructed in CAD software. Verification of gating systems was performed using the simulation software NovaFlow & Solid. The aim of the design change of the gating system is to reduce the amount of liquid metal used per casting, which can have a significant economic impact on industrial production. For this purpose, several simulations of the gating system of the casting were performed, while 2 which are the most representative for the mentioned problem were selected for the needs of the article. The main task of the simulation was to set the cellular network and conditions as close as possible to the reality of casting and the subsequent design and modification of the gating system.
Access status: Open Access ,
Problem of detecting inclusions by topological optimization
(2014) Faye, Ibrahima; Ndiaye, Mariama; Ly, Idrissa; Seck, Diaraf
In this paper we propose a new method to detect inclusions. The proposed method is based on shape and topological optimization tools. In fact after presenting the problem, we use topological optimization tools to detect inclusions in the domain. Numerical results are presented.
Access status: Open Access ,
Recent advances in low-gradient combustion modelling of hydrogen fuel blends
(2022) Buczyński, Rafał; Uryga-Bugajska, Ilona; Tokarski, Mieszko
Wydział Energetyki i Paliw
Low-gradient combustion (LGC) proved to be an effective alternative technology to reduce pollutant emissions and carbon footprint, specifically when combined with hydrogen as a fuel or blend component. This novel technology offers several advantages over conventional combustion regimes, including a more effective control of emissions and providing greater flexibility in fuel application. The impact of hydrogen on this regime is still not well-known, especially when it comes to the combustion of pure hydrogen and fuels with a high hydrogen content. In the last two decades, numerical simulations have become a powerful tool that facilitates the research and design of LGC, particularly in terms of stability of the process and the emission of pollutants. This article provides an up-to-date review of recent trends and theoretical knowledge in low-gradient combustion. This includes the guidelines and recommendations applied to LGC modelling. Comparisons have been made between the recently published modelling approaches presented by the authors, including a detailed assessment of the discrepancies in the temperature predictions. The challenges and limitations associated with the LGC combustion modelling of conventional fuels (i.e., natural gas, methane, syngas) blended with hydrogen are also discussed. The review demonstrated that the Eddy Dissipation Concept (EDC) is the most common turbulent chemical interaction model employed in LGC combustion simulations. The performance of the EDC can be significantly improved by variable constants $C_{𝛾}$ and $C_{𝜏}$ based on local turbulent Reynolds and Damköhler numbers. However, the most recent publications indicate that the flamelet-based approach can be considered as a promising (and more cost-effective) alternative to the EDC. Furthermore, the chemical kinetic studies considered in this review confirm that there is no detailed reaction mechanism capable of accurately predicting the temperature profile along with the emissions of the main species of interest, i.e., NOx, CO, CO2, and OH. Although GRI-Mech 2.11 is the most widely used mechanism in LGC simulations, providing satisfactory overall accuracy.
Access status: Open Access ,
Reverse Engineering and Computer Modelling in Archaeometallurgy for the Reconstruction of Heritage Objects Using Precision Casting and 3D Printing
(AGH University Press, 2025) Marlicka, Karolina; Fijołek, Andrzej; Garbacz-Klempka, Aldona; Piękoś, Marcin
This article presents an interdisciplinary approach to the reconstruction of a copper-alloy artefact using reverse engineering techniques combined with modern digital and manufacturing technologies. The research was motivated by the need to better understand historical casting techniques while preserving the integrity of cultural heritage objects through non-destructive methods. The study integrates 3D scanning, CAD-based modelling, numerical simulations, investment casting, and metal additive manufacturing. The geometry of the artefact was captured using high-resolution 3D scanning, enabling the development of two CAD models: one representing the preserved state of the object and a second reconstructed model with the missing fragment digitally restored. Both models were used for numerical simulations of mould filling, solidification, cooling, and porosity formation performed in MAGMASOFT® 6.1, allowing the assessment of technological feasibility and defect formation. Based on the simulation results, physical replicas were produced using investment casting and selective laser melting. The obtained numerical and experimental results were compared in terms of geometry reproduction, surface characteristics, and predicted versus observed casting behaviour. The study demonstrates that the combination of digital reconstruction, simulation tools, and experimental manufacturing provides a reliable framework for analysing historical metallurgical processes. The proposed methodology supports both scientific interpretation and the practical reconstruction of heritage objects and can be applied to a wide range of archaeometallurgical studies.
Access status: Open Access ,
Simulation of flow of fire gases in a ventilation network of a mine with a application of mathematical models of a different complexity implemented in the VENTGRAPH software
(2012) Dziurzyński, Wacław; Krawczyk, Jerzy; Krach, Andrzej; Pałka, Teresa
System programów komputerowych VENTGRAPH jest przeznaczony do prognozowania procesów przewietrzania w warunkach normalnych oraz w stanie awaryjnym jakim jest pożar i charakteryzuje się szerokimi możliwościami obliczeniowymi i łatwością obsługi programu jak i interpretacji wyników jego obliczeń. Stan przepływu powietrza w sieci wyrobisk można przewidywać przy pomocy badań symulacyjnych w oparciu o złożone modele matematyczne konstruowane w różnym stopniu uproszczenia. W artykule porównano warianty opisujące przepływ suchego lub wilgotnego powierza. Oba warianty uwzględniają odpowiednie modele ogniska pożaru a także przepływ mieszaniny powietrza i gazów z równoczesną wymianą ciepła wzdłuż dróg przepływu gazów pożarowych a także wpływ depresji pożaru. Modele te są efektem optymalnego doboru poszczególnych składników, dokonanego tak aby w możliwie krótkim czasie prowadzić dostatecznie wierną symulację rozpatrywanych zjawisk. Przedstawiono przykład prognozy procesu przewietrzania wywołanego otwartym pożarem podziemnym w wyrobiskach czynnych kopalń przewietrzanych prądem wznoszącym. Pozwoli to na dokonanie analizy jakościowej zmian wydatku przepływu mieszaniny powietrza i gazów pożarowych oraz sprawdzenia możliwości odwrócenia prądów powietrza, którymi przewietrzane są ściany. Uzyskane wyniki przedstawiono w postaci wykresów czasowych zmian obserwowanych parametrów.
Access status: Restricted ,
Teoretyczne opracowanie oraz symulacja systemu stabilizacji nanosatelit opartego na ferrofluidowym kole zamachowym
(Data obrony: 2018-01-29) Życzkowski, Jan
Wydział Elektrotechniki, Automatyki, Informatyki i Inżynierii Biomedycznej
Access status: Open Access ,
Un-recovered oil by vertical wells with water coning - assessment, prediction and remediation
(2008) Wojtanowicz, Andrzej; Hernandez, Juan
Water invasion mechanism - called water coning - affects vertical wells completed above the Oil-Water contact (OWC) in oil reservoirs with bottom water. The objective of this study was to quantify the amount of by-passed oil for a variety of the bottom water well-reservoir systems with water invasion to wells and to assess feasibility of downhole water sink completions to reduce oil by-passing. A large statistical population of possible reservoirs with bottom-water has been created using databases of actual reservoir properties worldwide. Dimensional analysis coupled with Monte Carlo method allowed converting statistics of reservoir properties into dimensionless group distributions. Then, the amount of by-passed oil was correlated with the dimensionless groups using three--level full-factorial designed experiments conducted with a reservoir simulator. A reservoir - well system with bottom water was modelled using a commercial black oil simulator with two concentric radial layers of oil pay and the aquifer zone having different sizes and properties. The resulting dimensionless correlations determine the expected value of by-passed oil at the end of well's operation. The correlations are general as they cover a wide range of reservoir-well systems. When the correlations are coupled with the reservoirs' population the results show that, for example, more than 25 percent of movable oil volume could be by-passed in one half of all the bottom-water reservoirs. The study also identifies dimensionless groups that mostly control water invasion - the end-point mobility ratio and well spacing. The results also reveal two mechanism of water invasion: coning or uniform OWC advancement. Numerical reservoir simulation is also used to investigate the well completion's length and placement that would minimize oil bypassing and optimize recovery. Single completions of different penetration (length) are compared to dual well completions with Downhole Water Drainage/Sink (DWS), for new wells and marginal (watered-out) wells. The results show that the best completion strategy for both the new and the marginal wells is the use of (or intervention with) DWS completions. DWS would delay water breakthrough, stimulate oil inflow by reducing water saturation around the well, and maximize Net Present Value by accelerating recovery.
Access status: Open Access ,
Uogólnienia metody elementów skończonych w inżynierskich symulacjach numerycznych ośrodka nieciągłego i dyskretnego
(Wydawnictwa AGH, 2010) Jakubowski, Jacek
Traditional finite element method is efficient and universal numerical simulation method, and implemented with many available software packages, also easy to use. Applied to simulations of discontinuities and discontinuous rock mass, it has got serials limitations. For the last several years some generalizations of this method have been developed with the use of new approximation techniques, particularly partition of unity. As a result of these developments mesh-free methods (MFree), enriched approximation methods (GFEM, XFEM) and numerical manifold method has been developed, basing on finite element method and finite difference method approaches. All the three groups of methods listed above have ability to model discontinuities without challenging and expensive remeshing. All of them can simulate continuous medium, discontinuous medium and model disintegration within a single numerical schema (each of them within different one). Completed with contact detection algorithms, they meet criteria of discrete element method. The above mentioned methods are still in their very early stages of development and many theoretical and practical problems need to be solved before they will be used in Civil Engineering and Rock Mechanics for practical applications. In the future, due to their advantages, they can offer an alternative for finite element method, distinct element method and other popular engineering simulation methods. The article presents the above mentioned methods and their possible applications for discontinuous and discrete medium simulation, particularly for the simulation of discontinuous rock mass.
Access status: Open Access ,
Uwarunkowania techniczne i ekonomiczne sekwestracji CO2 w złożu ropy naftowej
(2011) Wojnarowski, Paweł; Pyrzak, Paweł; Kosowski, Piotr; Stopa, Jerzy
Geological sequestration of CO2 generates costs connected with gas separation and injection, which in some situations makes this process unprofitable. Solution in this situation can be connection of this process with enhanced oil recovery. In majority oil fields only small part of oil is produced witch standard methods of exploitation. Experience from developed projects shows that CO2 injection into partially depleted reservoir can increase oil production making this process cost-effective. In this work technical and economical efficiency analysis of CO2 injection into Carpathian oil field was presented. Numerical simulation of production was developed. Results of multi variant simulations shows, that CO2 sequestration increase oil production, but there is no simply correlation between amount of injected gas and production increment. Capacity of typical Polish Carpathian oil fields is not sufficient for power plant emission. For this kind of process more suitable are large reservoirs, which guarantee stable injection during power plant lifecycle.
Access status: Open Access ,
Wykorzystanie modelowania komputerowego do prognozowania efektywności eksploatacji złóż ciężkiej ropy metodą cyklicznego zatłaczania pary
(2011) Stopa, Jerzy; Wojnarowski, Paweł; Pyrzak, Paweł
Heavy oil is a type of petroleum that is different from conventional petroleum insofar as it is much more difficult to recover from the subsurface reservoir. It has a much higher viscosity than conventional petroleum, and recovery of this petroleum type usually requires thermal stimulation of the reservoir. This study presents results of analysis of influence of thermal methods like Steam Assisted Gravity Drainage (SAGD) and Cyclic Steam Stimulation (CSS) in the one of heavy oil fields in Karpaty mountains. Numerical simulation was used for investigation of thermal EOR influence on recovery. Application of horizontal and vertical wells was analyzed. Variable volume of injected steam and different stages time steps were used. Results of analyses scenarios suggests that quantity of injected steam and length of injection cycles has large influence on oil recovery.