Wyniki wyszukiwania - BazTech

1

Modelowanie hydrodynamiki reaktora barbotażowego nowej konstrukcji

Jaschik Jolanta, Tańczyk Marek, Janusz-Cygan Aleksandra, Janecki Daniel, Mrozowski Jan

Przemysł Chemiczny

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2024

|

T. 103, nr 2

293--300

PL

Opracowano model CFD reaktora barbotażowego z dyspergatorem szczelinowym, stosowanego do głębokiego odsiarczania gazów zawierających duże ilości SO₂ , w celu implementacji procesu na większą skalę. Reaktor barbotażowy pracuje w układzie trójfazowym zawierającym ciecz, rozproszony gaz procesowy oraz fazę stałą (gips), czyli produkt reakcji. Zastosowano model Eulerian rozszerzony do trzech faz ze standardowym modelem turbulencji k-ɛ. Symulacje dotyczące hydrodynamiki prezentowanego reaktora wykonano dla różnych wartości parametrów procesowych. Walidacja opracowanego modelu CFD opierała się na porównaniu doświadczalnych i obliczonych wartości spadku ciśnienia gazu wlotowego oraz mocy mieszania. Stwierdzono bardzo dobrą zgodność tych parametrów. Przeprowadzono szczegółową analizę zjawisk hydrodynamicznych zachodzących w różnych obszarach reaktora. Analiza ta potwierdziła dobre warunki mieszania fazy gazowej i ciekłej w reaktorze o modelowanej konfiguracji. Takie warunki sprzyjają efektywnej absorpcji SO₂, co stwierdzono w badaniach eksperymentalnych.

EN

A CFD model of 1.5 m³ bubble reactor equipped with a slotted gas disperser used for deep desulfurization of SO₂ -rich gases was developed. The Eulerian model extended to 3 phases with standard k-ɛ turbulence model was used. Simulations of the hydrodynamics were made for different values of operating parameters. The validation of developed model was done by comparing the exp. and calc. values of the inlet gas pressure drop and the power of mixing. Anal. of the hydrodynamic phenomena in various areas of reactor confirmed good conditions for mixing the gas and liq. phases in the reactor with the modeled configuration. Such conditions favor effective absorption of SO₂ , which was found in experimental studies.

2

Modeling of the distribution of wind pressures of the building of the new safe confinement of the Chernobyl NPP

Skliarenko Dmytro, Krukovskyi Pavlo, Oliinyk Vladislav

Journal of New Technologies in Environmental Science

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2023

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Vol. 7, nr 1

24--27

EN

Distribution of wind pressures on the outer surface of the New Safe Confinement (NSC) is necessary to determine the unorganized air exchange from the NSC (outward or inward) with radioactive aerosols to the environment, since it is not hermetically sealed. The results show the discrepancy between the wind pressure distribution on the NSC outer surface in the small-scale 1:300 physical model of the NSC tested in the wind tunnel and the literature data. The computational CFD model of the NSC external air flow was developed to determine the distribution of pressures on the NSC surface at different wind directions and speeds. The adequacy of the calculated model is confirmed by the proximity of calculated and literature data, as well as calculations according to the European standard.

3

The influence of geometric characteristics of the buildings facades on the heat transfer to the wind flow

Basok Boris, Davydenko Boris, Pavlenko Anatoliy, Novikov Vladimir, Novitska Marina

Journal of New Technologies in Environmental Science

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2021

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Vol. 5, nr 1

11--22

EN

This paper presents the results of a numerical study of heat transfer from the external surfaces of freestanding structures in the surface layer of the atmosphere. Numerical models of structures have the same heat transfer area, but different heights and lengths. Numerical modeling of heat transfer from structures in a wind flow in a three-dimensional formulation made it possible to establish some features of convective heat transfer from enclosing structures, depending on the height of the building and the speed of the wind flow. In particular, it is shown that the dependence of the surface-averaged values of the heat flux density on the height of the building has a local minimum, after which the average heat flux density increases insignificantly with an increase in the height of the building.

4

Investigation of aerodynamic parameters of solar plane airfoil using CFD modeling

Jaszczur Marek, Papis Karolina, Książek Michał, Czerwiński Grzegorz, Wojtas Gabriel, Koncewicz Wojciech, Nabożna Sylwia, Wójcik Marcin

Computer Science

|

2021

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T. 22 (1)

123–142

EN

The technology of solar-powered aerial vehicles requires enormous financial support and further development. For this purpose, the computational fluid dynamic can be used. In order to carry out necessary analyses and model development in this research, ANSYS Fluent software was used. Using the first version of the AGH Solar Plane model, preliminary analysis of lift, drag and tearing off the stream was performed. Four new geometries were prepared on which the flattening of upper surfaces for fixing solar panels was tested. The results were validated in the aerodynamic tunnel using particle image velocimetry method. Taking into account all analyses, a number of recommendations have been prepared that will be implemented to create an aircraft, which meets all target requirements.

5

Analysis of dustiness state in a driven underground dog heading ventilating by auxiliary air-duct

Brodny Jarosław, Tutak Magdalena

Management Systems in Production Engineering

|

2020

|

nr 2 (28)

73--77

EN

Dustiness of the mine atmosphere during carrying out exploitation is one of the most hazardous factors threaten to health and life of employees. Also it is large hazard for all type of mechanical and electrical devices operating in mining headings. Coal dust is also very dangerous due to its possibility of explosion. Currently applied technologies of rock mass mining process, entire transport process of output and applied ventilation system cause that rock and coal dust is presented practically in each of the mining heading. Practically, is impossible to eliminate dust from mining headings. However, one can determine its parameters and potential ways its displacement. In the paper there is presented modeling research methodology of dustiness state in a driven dog heading. Developed model is the basis for this methodology, including the diphase flow of mixture of air and dust in the mining heading. Analysis was performed for real driven dog heading. Based on performed analyses, distributions of particular fraction and movement trajectories of selected dust grains were determined. Developed methodology gives a lot of opportunities for analysis of dustiness state in mining headings and in other compartments. It enables to determine parameters of particular grains and their impact on ventilation parameters of the air stream in the tested headings. Obtained results can also be used to reduce dust hazard.

6

Performance comparison of different aerodynamic shapes for autonomous underwater vehicles

Khalin Anatoliy, Kizilova Nataliya

Archive of Mechanical Engineering

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2019

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Vol. LXVI, nr 2

171--189

EN

A brief review of the existing autonomous underwater vehicles, their types, design, movement abilities and missions is presented. It is shown, the shape optimization design and enhancement of their efficiency is the main problem for further development of multipurpose glider technologies. A comparative study of aerodynamic performance of three different shape designs (the airfoil NACA0022 based (I), flattened ellipsoidal (II) and cigar-type (III) bodies of the same volumes) has been carried out. Geometrical modelling, meshing and computational fluid dynamics (CFD) simulations have been carried out with AnSys15.0. The pathlines and wall shear stress distributions have been computed to understand the advantages and disadvantages of each shape. The lift and drag coefficients, aerodynamic quality, power index and pitching moment have been computed. The higher efficiency of the shape I/shape II at higher/lower angles of attack (greater than 20o and less than 20o) has been found. The shape III develops high speeds at the same angles of attack and has higher manoeuvrability at relatively low aerodynamic quality. The comparative analysis of the flow capabilities of studied autonomous undersea vehicles proposes some design improvement for increasing their energy efficiency and flow stability.

7

Modelowanie CFD i badania aerodynamiczne żaluzji wywiewnych

Flaga-Maryańczyk A., Müller J., Schnotale J.

Ciepłownictwo, Ogrzewnictwo, Wentylacja

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2018

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T. 49, nr 2

71--75

PL

Przedstawiono wyniki przeprowadzonych badań laboratoryjnych oraz modelowania techniką obliczeniowej dynamiki płynów (CFD) żaluzji wywiewnej typu Z, stosowanej jako element końcowy systemu wentylacji. Tego typu elementy, zanim trafią do seryjnej produkcji, powinno poddać się testom zmierzającym do wyznaczenia charakterystyki przepływowej (straty ciśnienia będącej funkcją strumienia przepływającego powietrza). Testy można wykonać na stanowisku laboratoryjnym albo, unikając kosztów produkcji prototypów oraz czasochłonnego badania laboratoryjnego, posłużyć się modelowaniem numerycznym. Celem przeprowadzonej analizy była weryfikacja przyjętego modelu numerycznego poprzez porównanie z wartościami zmierzonymi dla analizowanej żaluzji wywiewnej oraz oszacowanie błędu popełnianego podczas obliczeń numerycznych w tego typu zastosowaniach. Wykonano pomiary ciśnienia statycznego analizowanej żaluzji wywiewnej w funkcji strumienia przepływającego powietrza. Pomiary przeprowadzono zgodnie z wymaganiami normy PN-EN 12238. Do numerycznej weryfikacji wyników pomiarów wykorzystano metodę obliczeniowej dynamiki płynów (ang. Computational Fluid Dynamics, CFD). Obliczenia numeryczne wykonano przy użyciu programu ANSYS Fluent. Uzyskano dobrą korelację wartości pomiarowych i wyników przeprowadzonych obliczeń numerycznych, co potwierdza zarówno trafność doboru modelu jak i precyzję wykonania pomiarów. Na tej podstawie można wnioskować, że analiza CFD nadaje się do tego typu zastosowań i powinna być włączona w proces projektowania, co pozwoli na ocenę skuteczności przyjętych rozwiązań projektowych we wstępnej fazie powstawania produktu.

EN

The article presents the results of laboratory tests and CFD modeling of a Z type exhaust grille, used as an air terminal device in the ventilation system. Such items, before they reach serial production, should be subjected to tests designed to determine the flow characteristic (the pressure loss being a function of the air flow). Tests can be made at the laboratory or, avoiding the costs of prototype production and time consuming laboratory testing, numerical modeling can be applied. The purpose of the performed analysis was to verify the adopted numerical model by comparing with the measured values for the analyzed exhaust grille and to estimate the errors made during numerical calculations in such applications. Laboratory tests included static pressure measurements as a function of the airflow. The measurements were done according to the requirements of EN 12238. The results of laboratory measurements were verified numerically using the Computational Fluid Dynamics (CFD) method. Numerical calculations were performed using ANSYS Fluent. Good correlation of data obtained during laboratory measurements and from numerical calculations confirms the accuracy of the selection of the model as well as the precision of the measurements. On this basis can be concluded that the CFD analysis is suitable for this type of application and should be an integral part of the design process, allowing to evaluate the effectiveness of the designed solutions.

8

Modeling of a mixture ﬂow of helium and methanol in thermocatalytic reactor and chemical reactions on the intermethallic phase of Ni3A

Ziółkowski P., Stajnke M., Jóźwik P.

Transactions of the Institute of Fluid-Flow Machinery

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2017

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nr 138

33--73

EN

In this paper, the speciﬁed issues that occurs in the numerical modeling of complex phenomena of chemical reactions intensiﬁed with forced ﬂuid ﬂow in the thermocatalytic reactor channels on the intermetallic phase of Ni3Al are presented. Based on the example of ﬂowing mixture containing helium contaminated by methanol in a horizontal microchannels, heated from the outside, received results of the experiment were shown and compared with computational ﬂuid dynamize calculations. However, standard version of commercial code have been expanded by user deﬁnedfunctions. These extensionstransformed the calculation mechanisms and algorithms of computational ﬂuid dynamize codes adapting them for the micro-ﬂow cases and increased chemical reactions rate on an interphase between ﬂuid and solid. Results obtained on the way of numerical calculations were compared with experimental data receiving satisfactory compliance.

9

How much a geometrical model of a honeycomb seal can be simplied in the CFD calculation

Stajnke M., Włodarski W.

Transactions of the Institute of Fluid-Flow Machinery

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2017

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nr 136

55--64

EN

This paper presents the influence of geometry simplification on the results obtained in the computational fluid dynamics simulation. The subject of simulation was part of the honeycomb seal located at the inlet to high pressure part of a steam turbine. There were three diferent geometrical models assumed in the calculations. First one was two-dimensional case and two others were three-dimensional, one with the radius of curvature and one without. Numerical simulations were performed for 15 sets of boundary conditions to compare flow characteristics for each geometrical case.

10

CFD simulation of heat transfer and fluid flow within metallic foam in forced convection environment

Boulahrouz S., Avenas Y., Chehhat A.

Mechanics and Mechanical Engineering

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2017

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Vol. 21, nr 3

611--635

EN

In the present study, a CFD simulation of forced convection in a rectangular block of aluminum foam is investigated. A two energy equations model with the Brinkman-Forchheimer extended Darcy model is considered in the CFD investigation. The governing equations are solved using COMSOL, a commercial multiphysics finite-element PDE solver. Three types of aluminum foam 10-, 20-, 40- pore per inch with different porosity are studied. A parametric study for the range of Reynolds number Re = 250-2000 and the imposed heat flux qw = 0:8−1:6 (W/cm2) is carried out to examine the thermal and the fluid flow behaviors of the aluminum foams. It is found that the plug flow conditions are prevalence for the aluminum foams. The 40-pore per inch aluminum foam has a better heat transfer performance with a larger pressure drop, followed by the 20-, and then by the 10- pore per inch. The validation of the simulation results is made against experimental data from the literature and showed a perfect agreement.

11

Miniature gas turbine with Variable Area Nozzle

Fulara S., Gieras M., Chmielewski M.

Archivum Combustionis

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2017

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Vol. 37 nr 2

127--138

EN

Current scientific knowledge related to miniature turbochargers and gas generators is still improving. Various concepts are being tested seeking performance enhancement. Variable Area Nozzle (VAN) system is one of them. It aims to optimize effective area nozzle controlling both: turbine entry temperature and mass flow rate. The article presents different variable geometry concepts and recent research on VAN applied to a miniature gas turbine at Warsaw University of Technology. VAN concept and related phenomena are discussed.

12

Modelowanie CFD osiadania statków kontenerowych podczas manewru wymijania na torze wodnym

Jachowski J., Krata P.

Autobusy : technika, eksploatacja, systemy transportowe

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2016

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R. 17, nr 4

64--71

PL

W artykule omówiono badania nad zastosowaniem zaawansowanych obliczeń numerycznej mechaniki płynów do wyznaczania trajektorii ruchu (w sześciu stopniach swobody) statku morskiego żeglującego na akwenie ograniczonym podczas manewru wymijania z innym statkiem. Uwzględniono jednocześnie zarówno oddziaływanie dna i brzegów kanału o zadanej geometrii jak również oddziaływanie wymijanego statku, co jest podejściem nowatorskim na skalę światową. Wyniki symulacji przeanalizowano pod wzglądem hydrodynamicznego zjawiska osiadania, powstającego podczas przejścia statku przez akwen ograniczony głębokością i brzegami kanału przy jednoczesnej interakcji z wymijanym statkiem. W obliczeniach wykorzystano geometrię typowego statku kontenerowego.

EN

Paper describes a research into ship’s squat phenomenon which is related to the safe entering of large ships into contemporary existing sea harbors. As the significant research effort in ship hydromechanics is devoted in recent years to the practical navigation problems, the Authors follow this trend and addressed the squat by means of CFD numerical simulations. The analysis of 6 DOF ship motion was performed, including the effects of shallow water, horizontal restrictions, extend of a channel and especially ship squat during passing by maneuver at a waterway. An exemplary case-study is carried out for a large container vessel. The obtained results were experimentally verified by comparison to one German experiment and own models tests. Such complex approach is a novelty worldwide.

13

Analysis of unsteady flow forces on the thermowell of steam temperature sensor

Kornet S., Sławiński D., Ziółkowski P., Badur J.

Transactions of the Institute of Fluid-Flow Machinery

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2015

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nr 129

25--49

EN

In this paper, 3D numerical analysis of unsteady flow forces acting on the thermowell of steam temperature sensor is presented. According to that purpose, the CFD+CSD (computational fluid–solid dynamics) approach has been used. The nonstationary of fluid acting on the thermowell such as: Strouhal frequency, amplitude of pressure, structure of vortex, peak of pressure, field of pressure, field of velocity, etc. are studied analytically and numerically. There have been examined two cases of flow with changing both temperature, pressure and mass flow rate (operating daily and night in the unit with capacity of 380 MWe). In accordance with the standards ASME PTC 19.3 TW-2010 the possibility of entry into resonance has been examined.

14

An advanced thermal-FSI approach of an evaporation of air heat pump

Felicjancik J., Ziółkowski P., Badur J.

Transactions of the Institute of Fluid-Flow Machinery

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2015

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nr 129

111--141

EN

The paper presents selected problems of numerical modelling of an advanced thermal- FSI (Fluid solid interaction) approach of evaporator of air heat pump. The example of a fin-tube evaporator has been studied, focusing on obtaining the heat exchanger characteristics applying two-phase flow model for the in-tube refrigerant flow. Special attention is given to heat transfer between separated medium for different air velocity and changed refrigerant mass flow in-tube.

15

CFD modeling of passive autocatalytic recombiners

Orszulik M., Fic A., Bury T.

Nukleonika

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2015

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Vol. 60, No. 2

347--353

EN

This study deals with numerical modeling of passive autocatalytic hydrogen recombiners (PARs). Such devices are installed within containments of many nuclear reactors in order to remove hydrogen and convert it to steam. The main purpose of this work is to develop a numerical model of passive autocatalytic recombiner (PAR) using the commercial computational fluid dynamics (CFD) software ANSYS-FLUENT and tuning the model using experimental results. The REKO 3 experiment was used for this purpose. Experiment was made in the Institute for Safety Research and Reactor Technology in Julich (Germany). It has been performed for different hydrogen concentrations, different flow rates, the presence of steam, and different initial temperatures of the inlet mixture. The model of this experimental recombiner was elaborated within the framework of this work. The influence of mesh, gas thermal conductivity coefficient, mass diffusivity coefficients, and turbulence model was investigated. The best results with a good agreement with REKO 3 data were received for k-ε model of turbulence, gas thermal conductivity dependent on the temperature and mass diffusivity coefficients taken from CHEMKIN program. The validated model of the PAR was next implemented into simple two-dimensional simulations of hydrogen behavior within a subcompartment of a containment building.

16

Badania numeryczne wpływu wysokości zawieszenia mieszadła PBT na jakość wytwarzanej zawiesiny lekkiej

Kacperski Ł., Karcz J.

Inżynieria i Aparatura Chemiczna

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2015

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Nr 6

328--329

PL

Przeprowadzono numeryczną analizę wpływu wysokości zawieszenia mieszadła PBT na jakość zawiesiny lekkiej w zbiorniku z przegrodami. Obliczenia numeryczne wykonano w oprogramowaniu ANSYS CFX 16.1 dla mieszalnika o średnicy wewnętrznej D = 0,295 m. Wysokość h zawieszenia mieszadła w zbiorniku wynosiła 0,67; 0,78 lub 0,89H. Na podstawie otrzymanych rozkładów stężenia cząstek ciała stałego w cieczy stwierdzono, że w zakresie przeprowadzonych obliczeń, profile stężenia cząstek istotnie zależą od pozycji mieszadła w zbiorniku.

EN

A numerical analysis of the effect of PBT impeller position on a quality of floating particles suspension produced in a baffled agitated vessel was carried out. The numerical computations were performed for a vessel of inner diameter D = 0.295 m, using ANSYS CFX 16.1 software. The off-bottom clearance of the impeller was equal to 0.67, 0.78 or 0.89H. On the basis of obtained distributions of particles concentration in liquid it was proved that, within the range of performed computations, the profiles of particles concentration significantly depended on the impeller position.

17

Computer modeling of a convective steam superheater

Trojan M.

Archives of Thermodynamics

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2015

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Vol. 36, no. 1

125--137

EN

Superheater is for generating superheated steam from the saturated steam from the evaporator outlet. In the case of pulverized coal fired boiler, a relatively small amount of ash causes problems with ash fouling on the heating surfaces, including the superheaters. In the convection pass of the boiler, the flue gas temperature is lower and ash deposits can be loose or sintered. Ash fouling not only reduces heat transfer from the flue gas to the steam, but also is the cause of a higher pressure drop on the flue gas flow path. In the case the pressure drop is greater than the power consumed by the fan increases. If the superheater surfaces are covered with ash than the steam temperature at the outlet of the superheater stages falls, and the flow rates of the water injected into attemperator should be reduced. There is also an increase in flue gas temperature after the different stages of the superheater. Consequently, this leads to a reduction in boiler efficiency. The paper presents the results of computational fluid dynamics simulations of the first stage superheater of both the boiler OP-210M using the commercial software. The temperature distributions of the steam and flue gas along the way they flow together with temperature of the tube walls and temperature of the ash deposits will be determined. The calculated steam temperature is compared with measurement results. Knowledge of these temperatures is of great practical importance because it allows to choose the grade of steel for a given superheater stage. Using the developed model of the superheater to determine its degree of ash fouling in the on-line mode one can control the activation frequency of steam sootblowers.

18

Modelowanie CFD konwekcyjnego przegrzewacza pary

Trojan M.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2014

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z. 86 [290], nr 2

269--276

PL

W artykule przedstawiono wyniki symulacji CFD w programie ANSYS-CFX przegrzewacza pierwszego stopnia w kotle OP-210M. Wyznaczono rozkład temperatury pary i spalin wzdłuż drogi ich przepływu, rozkład temperatury pary i spalin na wylocie z przegrzewacza oraz rozkład temperatury na ściance. Znajomość tych temperatur ma duże znaczenie praktyczne, ponieważ pozwala prawidłowo dobrać gatunek stali na dany stopień przegrzewacza. Korzystając z opracowanego modelu przegrzewacza do wyznaczenia stopnia jego zanieczyszczenia popiołem w trybie on-line można sterować częstotliwością aktywacji parowych zdmuchiwaczy sadzy.

EN

The paper presents the results of CFD simulations of the first stage superheater of the OP-210M boiler by using the ANSYS CFX software. The temperature distributions of the steam and flue gas along the way they flow will be determined. Furthermore, the temperature of the tube walls and temperature distribution of the steam and flue gas superheater outlet have been determined. Knowledge of these temperatures has great practical importance, because it allows to choose the grade of steel for a given superheater stage. Using the developed model of the super-heater to determine its degree of ash fouling in on-line mode one can control the activation frequency of steam soot blowers.

19

Impact of vehicle interior geometry on chosen volatile carcinogens concentration distribution in vehicle cabin

Zawiślak M.

Proceedings of ECOpole

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2013

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Vol. 7, No. 1

177--184

EN

The phenomena of volatile carcinogens pollution of interior atmosphere is an important issue on public health field. A car vehicle is a specific environment of human life where levels of volatile compounds concentration are much higher than ie in buildings (houses or offices). The VOCs sources can be divided on external (polluted air inlet through vehicle ventilation system) an internal (emission from cabin equipment materials). The volatile organic compounds are absorbed by human body mostly by respiratory system. The significant impact on toxicological characteristic of in-vehicle VOCs, in parallel with physical-chemical properties of the substance and exposition time, has also concentration distribution in vehicle cabin, especially the concentration on user head level. In the paper the results of CFD simulation of cabin geometry impact on chosen VOCs (benzene and toluene) distribution is presented. The geometrical model of vehicle cabin has been made and its insignificant modification was conducted to proof cabin geometry impact on driver exposure on the carcinogens carried out by ventilation system.

PL

Obecność kancerogenów z grupy lotnych połączeń organicznych, w szczególności w pomieszczeniach zamkniętych, jest istotnym problemem z zakresu zagadnień w obszarze zdrowia publicznego. Pojazd samochodowy jest środowiskiem życia człowieka, w którym poziomy stężeń substancji z grupy lotnych połączeń organicznych znacznie przekraczają stężenia w budynkach mieszkalnych czy biurowcach. Źródła LZO (benzenu i toluenu) w kabinie pojazdu można podzielić na dwa rodzaje: zewnętrzne (zanieczyszczone powietrze wprowadzane do wnętrza kabiny za pomocą systemu wentylacyjnego pojazdu) oraz wewnętrzne (emisja z materiałów stosowanych we wnętrzu kabiny pojazdu). Lotne związki organiczne przedostają się do organizmu ludzkiego głównie za pomocą dróg oddechowych, a na ocenę ich wpływu toksycznego na zdrowie użytkowników oprócz właściwości fizykochemicznych substancji oraz czasu ekspozycji ma również znaczący wpływ dystrybucja tych substancji we wnętrzu pojazdu, w szczególności ich koncentracja na wysokości głowy użytkownika. W niniejszym artykule zaprezentowano wyniki symulacji komputerowej (metoda CFD) cyrkulacji powietrza wewnątrz kabiny pojazdu w aspekcie rozkładu wybranych kancerogenów z grupy LZO. Wykonano model geometryczny kabiny pojazdu, a następnie poprzez nieznaczne modyfikacje geometrii wnętrza udowodniono wpływ geometrii na narażenie kierowcy na kontakt z lotnymi substancjami o charakterze kancerogennym wprowadzanymi poprzez system wentylacyjny pojazdu.

20

CFD modeling of pulverized coal combustion in air and oxy atmosphere - NOx and SO2 formation

Pawlak-Kruczek H., Zawiślak M.

Proceedings of ECOpole

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2013

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Vol. 7, No. 1

149--154

EN

Despite the fact that alternative energy sources sector has been rapidly developed since last years, coal combustion as a major fossil-fuel energy resource (especially in Poland) will continue being a major environmental concern for the next few decades. To meet future targets for the reduction of toxic and greenhouse gases emission new combustion technologies need to be developed: pre-combustion capture, post-combustion capture, and oxy-fuel combustion. This paper deals with the air-fried and oxy-fuel coal combustion (pulverized coal) combustion, and its impact on pollutants (NOx and SO2) formation. For CFD (Computational Fluid Dynamics) modeling of media flows and coal combustion process the laboratory model of combustion reactor was applied. The material input was set based on technical-elementary analysis of pulverized coal used in experiment and sieves grain-size analysis. Boundary conditions (media flows intensities and temperatures) were set based on laboratory experimental measurements. Radiation case-sensitive WSGGM model (weighted - sum - of - gray gases model) was used for calculation. The modeling was proceed for different combustion parameters in air and OXY atmosphere in oxygen/fuel ratio variation and fuel humidity variation function.

PL

Pomimo faktu gwałtownego rozwoju sektora alternatywnych źródeł energii w ostatnich dziesięcioleciach, spalanie węgla jako najważniejszego źródła energii konwencjonalnej (w szczególności w Polsce) jest bardzo istotnym zagadnieniem w aspekcie ochrony i inżynierii środowiska. Nowe wyzwania w zakresie obniżania emisji związków toksycznych, a także gazów cieplarnianych wymuszają rozwój w zakresie innowacyjnych technologii spalania węgla: pierwotnych (na etapie substratów) oraz wtórnych (na etapie produktów), a także modyfikacji procesu spalania (atmosfera OXY). W artykule przedstawiono zagadnienie formowania się zanieczyszczeń (NOx oraz SO2) powstających podczas procesu spalania pyłu węglowego w atmosferze powietrza oraz atmosferze OXY. Do obliczeń metodą CFD (przepływu i spalania mieszanki powietrzno-węglowej wykorzystano model laboratoryjnego pieca opadowego. Jako warunki brzegowe do obliczeń zastosowano wyniki analiz techniczno-elementarnych pyłu węglowego, przedziały frakcyjne cząstek ustalono na podstawie analizy sitowej. Warunki brzegowe (temperaturę pieca, doprowadzanego powietrza oraz paliwa, natężenia przepływu powietrza pierwotnego i wtórnego) ustalono na podstawie pomiarów rzeczywistych w warunkach laboratoryjnych. W celu zamodelowania spalania z uwzględnieniem radiacji wykorzystano model WSGGM (weighted-sum-of-gray-gases model). Obliczenia z uwzględnieniem radiacji oraz powstawania zanieczyszczeń NOx i SO2 prowadzono dla warunków spalania w powietrzu oraz przyjęto zróżnicowane atmosfery OXY. Obliczenia prowadzono w funkcji wartości współczynnika lambda oraz dla różnych wartości wilgotności paliwa.