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1
Content available Investigations of Dual Plug Argon Blowing for Efficient Mixing at Ladle Furnace Station
Warzecha Marek, Hutny A., Warzecha P., Kutyła Z., Merder T.
Archives of Metallurgy and Materials
|
2021
|
Vol. 66, iss. 2
561--572
EN
The article presents the results of model research concerning the change of technology of argon blowing into liquid steel at the ladle furnace, using the dual plug system. The results of numerical simulations were verified with experimental data carried out on the water model device. The verified model was used to perform numerical simulations to predict the impact of using a new gas injection technology - with different flow rates - on the time to achieve the assumed degree of metal chemical homogenization after alloy addition. Simulation results show that argon blowing metal bath in dual plug mode can effectively reduce mixing time compared to conventional technology with the same gas flow rates. Generally, the use of the dual plug system is beneficial for reducing the bath mixing time, however, the assumed optimal proportion of gas blown through individual plug should be followed. Finally, numerical predictions were used to perform experimental melt under industrial conditions. Industrial verification has clearly confirmed the validity of numerical modeling and showed that also in industrial conditions, a shorter time of chemical homogenization was obtained for the dual plug system.
2
Content available Hydrodynamic conditions of flow in the tundish depending on selected technological parameters for different steel groups
Warzecha M., Merder T., Warzecha P., Hutny A. M.
Archives of Metallurgy and Materials
|
2019
|
Vol. 64, iss. 1
65--70
EN
The presented results of investigations are part of a larger study focused on the optimization of the flow and mixing of liquid steel in the industrial tundish of continuous casting machine. The numerical simulations were carried out concern the analysis of hydrodynamic conditions of liquid steel flow in a tundish operating in one of the national steelworks. Numerical simulations were performed using the commercial code ANSYS Fluent. The research concerns two different speeds of steel casting. In real conditions, these speeds are the most commonly used in the technological process when casting two different groups of steel. As a result of computational fluid dynamics (CFD) calculations, predicted spatial distributions of velocity and liquid steel turbulence fields and residence time distribution (RTD) curves were obtained. The volume fractions of different flows occurring in the tundish were also calculated. The results of the research allowed a detailed analysis of the influence of casting speed on the formation of hydrodynamic conditions prevailing in the reactor.
3
Content available remote Wpływ stężenia na wartość progowej dawki koagulantu dla zawiesiny bentonitowej w procesie koagulacji
Hilger B., Warzecha P.
Przemysł Chemiczny
|
2017
|
T. 96, nr 8
1677--1679
PL
Badano koagulację objętościową zawiesiny bentonitowej. Prace obejmowały zbadanie zawiesiny pod kątem uziarnienia, składu chemicznego i fazowego oraz zależności pomiędzy stężeniem zawiesiny a mętnością. Wyznaczono zależność dawki koagulantu od stężenia zawiesiny, co może pomóc przy określeniu wartości dawki progowej koagulantu podczas badania procesu koagulacji lub projektowania wysokowydajnych urządzeń sedymentacyjnych dla zawiesin podobnego pochodzenia w procesie uzdatniania wody.
EN
Bentonite suspensions were sepd. by sedimentation after addn. of com. coagulants. Particle size distribution, chem. and phase compns. were detd. Relationships between concn. of the solids in suspension and its turbidity and between coagulant dose and the concn. were established to improve the coagulation process and to design the high–performance sedimentation equipment.
4
Content available Application of High Flow Rate Gas in the Process of Argon Blowing Trough Steel
Merder T., Pieprzyca J., Warzecha M., Warzecha P.
Archives of Metallurgy and Materials
|
2017
|
Vol. 62, iss. 2A
905--910
EN
The article demonstrates results of modelling research tests concerning the analysis of possibilities of blowing gas into the metal bath at high flow rates in a steel ladle with a nominal capacity of 50 Mg. Various configurations concerning of gas introduction into the steel ladle were analysed. There were considered cases of blowing into the metal bath via one, two or three purging plugs, being installed on the bottom and via additional support for blowing the gas from the top through the lance. Results obtained from the water model of the reactor were verified with the results of numerical simulations.
5
Wpływ typu kształtki gazoprzepuszczalnej na dyspersję gazu w kąpieli stalowej
Merder T., Warzecha P., Warzecha M., Pieprzyca J., Moycho J.
Hutnik, Wiadomości Hutnicze
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2016
|
Vol. 83, nr 11
501--503
PL
W pracy przedstawiono wyniki symulacji numerycznych przepływu dwufazowego gaz-ciekła stal z wykorzystaniem modelu DiscretePhase Model (DPM). Testowano różne warunki początkowe i brzegowe wprowadzania gazu do cieczy. Szczegółowo analizowano dwa warianty sposobu wprowadzania argonu, w pierwszym wydostaje się on przez zdefiniowaną grupę punktów dyskretnych na powierzchni kształtki, a w drugim przez osiem szczelin zdefiniowanych na powierzchni kształtki. Prezentowane wyniki badań stanowią jeden z etapów hybrydowych badań modelowych związanych z opracowaniem nowatorskiej technologii przetwarzania złomu, pochodzącego z kordu opon samochodowych, poprzez jego roztopienie w piecu indukcyjnym i dalszą obróbkę w kadzi stalowniczej.
EN
Paper presents the results of numericalsimulations of two-phase flow (gas-liquid steel) using a DiscretePhase Model (DPM). Differentinitial and boundary conditions of introducing of gas into the liquid were tested. A detailedanalysis was performed for twospecificvariants of introducing argon: in a firstcase - gasisintroduced via defined group of discrete points on the porous plug surface, and in a second case; gas was introduced via eight slits defined at the plug surface. The results of presented research represent one of the stages of the hybrid modeling studies, related to the development of an innovative technologies of processing of scrap originating from the cord tires by melting it in induction furnace and further processing in the ladle.
6
Analiza wpływu zastosowanego modelu matematycznego na prognozowaną dyspersję gazu w kąpieli stalowej
Warzecha M., Warzecha P., Merder T., Pieprzyca J., Mazurkiewicz J.
Hutnik, Wiadomości Hutnicze
|
2016
|
Vol. 83, nr 11
487--490
PL
W artykule przedstawiono wyniki badań CFD, które są częścią badań modelowych dotyczących opracowania nowatorskiej technologii przetwarzania złomu, pochodzącego z kordu opon samochodowych. Wyniki badań zawarte w niniejszej pracy dotyczą symulacji CFD przepływu dwufazowego gaz-ciekła stal, z wykorzystaniem dwóch różnych modeli matematycznych: Discrete Phase Model (DPM) oraz Volume of Fluid (VOF). W obliczeniach wykorzystano komercyjny program ANSYS Fluent. Analizowano odwzorowanie kolumny gazowo-cieczowej poprzez oba modele.
EN
The article presents the results of the CFD calculations, which are the part of the modeling studies, related to the development of an innovative technologies of processing of scrap originating from the cord tires. The test results presented in this paper apply to CFD simulation of two-phase (gas-liquid steel) plume, using two different mathematical models: Discrete Phase Model (DPM) and Volume of Fluid (VOF). The commercial computing program Ansys Fluent was used to perform calculations. The projection of gas-liquid plume by both models was analyzed.
7
Content available Optimization of Steel Flow in the Tundish by Modifying its Working Area
Warzecha P., Hutny A. M., Warzecha M., Merder T.
Archives of Metallurgy and Materials
|
2016
|
Vol. 61, iss. 4
2071--2078
EN
Presented paper describes model investigations carried out on six-strand continuous casting tundish. Numerical analysis is based on simulations performed with the use of commercial code ANSYS Fluent. The analysis concerns determination of hydrodynamic conditions of the flow in the analysed tundish, with nominal capacity of 22 Mg, and its optimisation by modification of the flow structure in the tundish working area. Four different flow control devices (FCD) were proposed. Results of investigations presented in the paper include the distribution of velocity vectors and distribution of temperature and turbulence kinetic energy. Additionally, for more detailed comparative analysis, the macroscopic characteristics of residence time distribution (RTD) in the reactor, and the transition zone ranges were determined for each of the variants.
8
Content available Experimental Methods of Validation for Numerical Simulation Results on Steel Flow through Tundish
Pieprzyca J., Warzecha P., Merder T., Warzecha M.
Archives of Metallurgy and Materials
|
2016
|
Vol. 61, iss. 4
2057--2060
EN
The article presents experimental results on the impact of tundish flow regulator influencing the liquid steel flow course. The research was conducted based on the hybrid modelling methods understood as a complementary use of Computational Fluid Dynamics (CFD) methods and physical modelling. Dynamic development of numerical simulation techniques and accessibility to highly advanced and specialized software causes the fact that these techniques are commonly used for solving problems related to liquid flows by using analytical methods. Whereas, physical modelling is an important cognitive tool in the field of empirical identification of these phenomena. This allows for peer review and specification of the researched problems. By exploiting these relationships, a comparison of the obtained results was performed in the form of residence time distribution (RTD) curves and visualization of particular types of liquid steel flow distribution zones in the investigated tundish.
9
Content available Large-Eddy Simulations of a Flow Characteristics in a Multi-Strand Continuous Casting Tundish
Merder T., Warzecha M., Warzecha P.
Archives of Metallurgy and Materials
|
2015
|
Vol. 60, iss. 4
2923--2926
EN
n order to increase the efficiency and quality of the steel-making process a numerous studies are conducted at the various stages of the process, including continuous casting of steel. Researchers still search for new models and improve existing one, so that the specific of the process is accuratelly reproduced. One way to increase the accuracy of numerical simulation, is to apply the LES (Large Eddy Simulation) method to simulate steelmaking processes. The article presents the results of numerical analysis on the flow characteristics (RTD curves) of liquid steel in the tundish facility for the continuous casting of steel. Numerical simulations have been performed using RANS (Reynoldsaveraged Navier-Stoke) and LES methods, and those results have been verified in industrial conditions.
PL
W celu zwiększenia efektywności i jakości procesu wytwarzania stali prowadzone są liczne badania modelowe różnych etapów tego procesu, w tym ciągłego odlewania stali. Wciąż poszukuje się nowych modeli i udoskonala dostępne, tak aby możliwie najbardziej wiernie oddać specyfikę procesu. Jednym ze sposobów na zwiększenie dokładności obliczeń numerycznych, jest zastosowanie do symulacji procesów stalowniczych metody wielkich wirów LES (Large Eddy Simulation). W artykule, przedstawiono wyniki badań numerycznych dotyczących analizy charakterystyki przepływu (krzywe RTD) ciekłej stali w kadzi pośredniej urządzania do ciągłego odlewania stali. Do badań wykorzystano metody RANS (Reynoldsaveraged Navier–Stoke) oraz LES, a wyniki zweryfikowano w warunkach przemysłowych.
10
Content available Investigation of the Flow Structure in the Tundish with the Use of Rans and Les Methods
Warzecha M., Merder T., Warzecha P.
Archives of Metallurgy and Materials
|
2015
|
Vol. 60, iss. 1
215--220
EN
The liquid steel flow structure in the tundish has a very substantial effect on the quality of the final product and on efficient casting conditions. Numerous model studies are being carried out to explain the effect of the tundish working conditions on casting processes. It is necessary to analyze the structure of liquid steel flow, which is strongly supported with numerical modeling. In numerical modeling, a choice of a proper turbulence model is crucial as it has a great impact on the flow structure of the fluid in the analyzed test facility. So far most numerical simulations has been done using RANS method (Reynolds-averaged Navier-Stokes equations) but in that case one get information about the averaged values of the turbulent flow. In presented study, numerical simulations using large eddy simulations (LES) method were used and compared to RANS results. In both cases, numerical simulations are carried out with the finite-volume commercial code AnsysFluent.
PL
Struktura przepływu ciekłej stali w kadzi pośredniej ma bardzo istotny wpływ na warunki odlewania, a tym samym na jakość wyrobu końcowego. W celu określenia struktury przepływu w kadzi oraz analizy jej wpływu na warunki pracy urządzenia do ciągłego odlewania stali (COS) prowadzone są liczne badania modelowe: fizykalne i numeryczne. W modelowaniu numerycznym, wybór odpowiedniego modelu turbulencji jest kluczowy, ponieważ ma ogromny wpływ na strukturę przepływu płynu w analizowanym obiekcie badawczym. Do tej pory, największą ilość symulacji numerycznych przeprowadzono z wykorzystaniem metody RANS (Reynolds-averaged Navier-Stokes equations). W przypadku tej metody dostajemy jednak jedynie informacje o uśrednionych wartościach przepływu turbulentnego, z jakim mamy do czynienia w kadziach pośrednich. W prezentowanej pracy natomiast, przedstawiono wyniki symulacji numerycznych przeprowadzonych z wykorzystaniem metody wielkich wirów (Large Eddy Simulation, LES) i porównano je z wynikami RANS. W obu przypadkach, symulacje numeryczne zostały przeprowadzone z wykorzystaniem komercyjnego kodu AnsysFluent.
11
Content available Possibilities of 3D Model Application in the Process of Aluminium Refining in the Unit With Rotary Impeller
Merder T., Saternus M., Warzecha P.
Archives of Metallurgy and Materials
|
2014
|
Vol. 59, iss. 2
789--794
EN
Both primary and secondary aluminium have to be refined, especially by barbotage process. To know better the mechanism of blowing argon through aluminium in reactors with rotary impellers, numerical modelling is applied. It allows to obtain useful information like: the level of velocity field or participation of gaseous phase. However, numerical analysis requires choosing the proper model which would describe the physical phenomena occurring in the process. So, AnsysFluent code was used in the research. It allows to calculate the two-phase liquid flow for the 2D and 3D co-ordinate systems. Results of calculations for the 3D case can describe more accurately the spatial picture of the movement trajectory of the blown gas bubbles. Calculations were done for the flow rate of refining gas equal 5 dm3 /min and for two cases: when there was no rotation and with 300 rpm rotary impeller speed.
PL
Zarówno aluminium pierwotne, jak i wtórne musi zostać poddane rafinacji, np. poprzez barbotaż. W celu poznania mechanizmu przedmuchiwania aluminium argonem w reaktorach z rotorami stosuje się modelowanie numeryczne. Pozwala ono uzyskać takie informacje jak; określenie pól prędkości czy udziału fazy gazowej. Modelowanie matematyczne wymaga jednakże odpowiedniego modelu określającego warunki fizyczne panujące w procesie. Tak więc, do obliczeń zastosowano kod AnsysFluent, który pozwala na obliczenia przepływów dwufazowych dla dwu- (2D) i trójwymiarowego układu współrzędnych (3D). Wyniki obliczeń dla układu 3D mogą bardziej dokładnie opisać trajektorie ruchu wdmuchiwanych pęcherzyków gazowych. Obliczenia przeprowadzono dla natężenia gazu 5 dm3 /min przy braku rotacji oraz przy prędkości obrotowej 300 obr/min.
12
Content available Dobór konstrukcji wypełnienia przeciwprądowego oraz prostopadłoprądowego w laboratoryjnym osadniku wielostrumieniowym
Kowalski W. P., Warzecha P., Banaś M., Kołodziejczyk K.
Inżynieria i Aparatura Chemiczna
|
2013
|
Nr 3
200--201
PL
Opisano koncepcyjne rozwiązanie osadnika laboratoryjnego mogącego pracować opcjonalnie w wariancie prostopadłoprądowej oraz przeciwprądowej sedymentacji wielostrumieniowej. Przedstawiono dobór i doskonalenie konstrukcji wypełnienia wielostrumieniowego osadnika w celu uzyskania porównywalnych wartości prędkości przepływu płynu przez kolejne przewody. Poprawność doboru kontrolowano obserwując przepływ płynu barwionego markerem optycznym przez elementy konstrukcji komór osadnika.
EN
Conceptual solution of a laboratory setter which can work as a counter-cur¬rent or cross-current multistream unit is presented in the paper. The selection and design improvement of the lamella settler in order to obtain comparable values of fluid flow velocities through subsequent conduits are shown. Selection correctness was monitored via visual observations of fluid colored with an optical marker flowing through constructional elements of settl chambers.
13
Content available remote Flow modeling in a laboratory settling tank with optional counter-current or cross-current lamella
Kołodziejczyk K., Banaś M., Warzecha P.
Journal of Achievements in Materials and Manufacturing Engineering
|
2012
|
Vol. 53, nr 1
28--36
EN
Purpose: Design of laboratory lamella settling tank used in the laboratory researches of sedimentation process, optionally in either cross-current or counter-current. Design/methodology/approach: This paper presents a selection of geometric parameters of the device made using numerical methods to analyze the flow in designed settling tank. Findings: As a result of analyses, of the final device design was developed that allows it to obtain the proper distribution of flow velocity. The simulations allowed the selection of the proper construction of the tank, in which the velocity distributions in successive channels are comparable to the fulfillment of lamella, which will allow it to charge uniform stream of liquid (suspension). Practical implications: The use of numerical methods of modeling the flow in the settling tank allowed to fine-tune the design of the device at the early stage, and in particular the parameters of the distribution of suspension. Originality/value: The settling tank allows sedimentation to take place in both configurations with the preservation of an identical sedimentation surface. This concept allows a comparison of processes in these systems at a given identical surface load.
14
Content available remote CFD modelling of non-metallic inclusions removal process in the T-type tundish
Warzecha M., Merder T., Warzecha P.
Journal of Achievements in Materials and Manufacturing Engineering
|
2012
|
Vol. 55, nr 2
590--595
EN
Purpose: The aim of performed research is to diagnose the possibilities of non-metallic inclusions removal from liquid steel flowing through the two-strand T-type tundish with its current configuration. Design/methodology/approach: Research were performed with numerical simulations. Initial conditions for inclusions distribution were obtained earlier with experimental measurements during industrial casting conditions. Findings: Numerical simulations let to investigate the flow field structure of liquid steel in the tundish and its impact on inclusions trajectories and separation from steel to the slag. Moreover it was found that standard boundary condition (trap) available in commercial code for disperse phase is not suitable to model complex physical phenomena occurring at the steel-slag interphase. Research limitations/implications: Commercial use of computational codes for the analysis of work and design of industrial facilities is a relatively inexpensive tool Practical implications: The research results presented in the paper can be used for steel production of high purity steels. Originality/value: Presented results may contribute to significant improvements in process efficiency of investigated tundish.
15
Symulacje numeryczne spalania pyłu węglowego w atmosferze O2-CO2
Warzecha P, Bogusławski A.
Archiwum Spalania
|
2012
|
Vol. 12, nr 3
145--151
PL
W pracy przedstawione zostały wyniki symulacji numerycznych spalania pyłu węglowego z wykorzystaniem metody RANS. Obliczenia przeprowadzone zostały dla geometrii palnika wirowego, którego stanowisko pomiarowe zlokalizowane jest w Instytucie Wymiany Ciepła i Masy na uniwersytecie RWTH Aachen w Niemczech [5]. Stanowisko pomiarowe składa się z rury opadowej o długości 2,1m oraz średnicy wewnętrznej 0,4m. Palnik zlokalizowany jest w górnej części układu pomiarowego dla którego stopień zawirowania wynosi 1,2.
EN
The paper presents results of numerical simulations of pulverized coal combustion process in swirl burner using RANS method. Numerical simulations have been performed for the oxyfuel test facility located at the Institute of Heat and Mass Transfer at RWTH Aachen University (Toporov et al. 2008). The test rig is a vertical, cylindrical furnance with a length of the combustion chamber of 2.1m and an inner diameter of 0.4m.
16
Content available remote Numerical study of wake effect on rough wall boundary layer
Elsner W., Warzecha P.
Mechanics and Mechanical Engineering
|
2011
|
Vol. 15, nr 3
227-236
EN
The paper deals with the problem of wakes effect and surface roughness, which influences the performance and flow of axial turbine and compressor stages. The accurate and reliable prediction of both effects are of great interest of designers. The paper discusses the results of verification of boundary layer modeling approach, which rely on a γ - Re θt model proposed by Menter et al. (2004) extended by laminar-turbulent transition correlations proposed by Piotrowski et al. (2008) and Stripf et al. (2008) correlations, which take into account the effects of surface roughness.
17
Content available remote Modeling of Rough Wall Boundary Layers with an Intermittency Transport Model
Elsner W., Warzecha P.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
|
2010
|
Vol. 14, No 3
271-282
EN
The paper presents a new extension of the -Ret model to account for both the laminar-turbulent transition and the surface roughness. The new modeling approach takes into account the pressure gradient, turbulence intensity and roughness height and density. In the transition region both the intermittency transport equation and the momentum thickness Reynolds number Ret transport equation, supplemented by the correlation of Stripf et al. (2009) suitable for rough wall boundary layers are used. An additional modification of the SST turbulence model allows for modeling a full turbulent boundary layer over surfaces with sand roughness. A comprehensive validation of the new method using transitional and fully turbulent test cases was performed. Flat plate data with a zero and non-zero pressure gradient test case as well as a high pressure turbine blade case were used for this purpose The studies proved that the new modeling approach appeared to be sufficiently precise and enabled a qualitative prediction of the boundary layer development for the tested flow configurations.
18
LES Modelling of Pulverized Coal Combustion in O2/CO2 mixture
Warzecha P., Bogusławski A.
Archivum Combustionis
|
2010
|
Vol. 30 nr 3
215-224
EN
The paper presents results of pulverized coal combustion process modelling using Large Eddy Simulation. First the methodology for the testing of mesh resolution is presented. The combustion process was carried out using single mixture fraction approach. Results were obtained for different ratio of O2/CO2 in the oxidizer.
19
Content available remote Transition modelling with intermittency transport model
Elsner W, Warzecha P
Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka
|
2008
|
nr 133
119--128
EN
The paper presents validation of -Reθ model proposed by Menter at al (2006), which was extended by in-house correlations on onset location and transition length. The tests performed were based on experimental data on the flat plate test cases where l-t transition, laminar separation and reattachment were present. The model was applied both for steady and unsteady calculations. It was shown that the model was able to reproduce some essential flow features related to the separated transition and the simulations reveal good agreement with the experimental results.
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