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Wyszukujesz frazę "dissipation rate" wg kryterium: Temat


Wyświetlanie 1-7 z 7
Tytuł:
Energy feature of a multi-flow column flotation process
Autorzy:
Cheng, G.
Yu, Y.
Ma, L.
Xia, W.
Xu, H.
Powiązania:
https://bibliotekanauki.pl/articles/109768.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
flotation column
turbulent kinetic energy
turbulent dissipation rate
bubble
Opis:
A cyclonic-static micro-bubble flotation column (FCSMC) has been widely used in mineral separation. FCSMC includes countercurrent, cyclone and jet flow mineralization zones in a single column. In this study, the energy feature of the three different zones was compared. The turbulent flow was evaluated in terms of the turbulent kinetic energy (k) and the turbulent dissipation rate (ε). An appropriate computing model was determined by comparing the flow field value measured by PIV with the results of the Fluent numerical simulation. Jet flow separation exhibited the maximum k and ε values among the three columns, whereas counter-current separation displayed the minimum values. The high circulating volumetric flowrate means great energy input and turbulent intensity. The higher turbulent dissipation rate, the smaller the bubble is. The better performance of the FCSMC was mainly attributed to the multiple mineralization steps. The floatability of mineral particles gradually decreases with an increase in flotation time, the mineralization energy gradually increased to overcome the decrease in mineral floatability. By contrast, the countercurrent was beneficial for recovering the coarse particles, and the jet flow was beneficial for recovering the fine particles.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 2; 1266-1284
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Clopyralid dissipation in the soil contaminated with heavy metals
Autorzy:
Kucharski, M.
Kalitowska, O.
Powiązania:
https://bibliotekanauki.pl/articles/123760.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
heavy metals
Cu
Zn
herbicide
soil
dissipation rate
clopyralid
Opis:
The aim of the studies was to determine the influence of copper and zinc contamination on clopyralid dissipation in soil. The experiment was carried out in laboratory conditions (plant growth chamber). Clopyralid was applied to three different soils [similar textures, pH, organic carbon content and contrasting copper and zinc content: soil natural contaminated with Cu and Zn (S1), soil with natural low Cu and Zn concentration (S2) and soil S21 prepared in the laboratory (S2 soil additionally contaminated with Cu and Zn salts in the amounts equivalent to contamination level of S1 soil)]. Soil samples were taken for analyses for 1 hour (initial concentration) and 2, 4, 8, 16, 32, 64 and 96 days after treatment. Clopyralid residue was analysed using GC/ECD (gas chromatography with electron capture detector). Good linearity was found between logarithmic concentration of clopyralid residues and time. The differences in Cu and Zn content influenced the clopyralid decay in soil. The values of DT50 obtained in the experiment ranged from 21 to 27 days. A high concentration of Cu and Zn in soil slowed down clopyralid degradation (the DT50 value was higher – 25–27 days).
Źródło:
Journal of Ecological Engineering; 2015, 16, 1; 38-42
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of fuel spills on Arctic soil, 32 years later (Hornsund, Svalbard)
Autorzy:
Krzyszowska Waitkus, Anna J.
Waitkus, Brian
Powiązania:
https://bibliotekanauki.pl/articles/2041843.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Arctic
Spitsbergen
Polish Polar Station
soil pollution
total petroleum hydrocarbons
dissipation rate
Źródło:
Polish Polar Research; 2019, 40, 4; 295-309
0138-0338
2081-8262
Pojawia się w:
Polish Polar Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the mechanism of gas bubble break-up in liquids during the self-aspirating impeller operation
Autorzy:
Stelmach, J.
Kuncewicz, Cz.
Musoski, R.
Powiązania:
https://bibliotekanauki.pl/articles/185320.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
self-aspirating impeller
PIV
gas bubble size distribution
energy dissipation rate
gas bubble sizes
pęcherzyk gazu
rozpraszanie energii
Opis:
Feasibility of a model of gas bubble break-up and coalescence in an air-lift column enabling determination of bubble size distributions in a mixer with a self-aspirating impeller has been attempted in this paper. According to velocity measurements made by the PIV method with a self-aspirating impeller and Smagorinski’s model, the spatial distribution of turbulent energy dissipation rate close to the impeller was determined. This allowed to positively verify the dependence of gas bubble velocity used in the model, in relation to turbulent energy dissipation rate. Furthermore, the range of the eddy sizes capable of breaking up the gas bubbles was determined. The verified model was found to be greatly useful, but because of the simplifying assumptions some discrepancies of experimental and model results were observed.
Źródło:
Chemical and Process Engineering; 2016, 37, 3; 441-457
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Local Turbulent Energy Dissipation Rate in a Vessel Agitated by a Rushton Turbine
Autorzy:
Šulc, R.
Pešava, V.
Ditl, P.
Powiązania:
https://bibliotekanauki.pl/articles/185567.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
mixing
Rushton turbine
local turbulent energy dissipation rate
energy spectrum
function
fluctuation velocity
mieszanie
turbina Rushtona
rozpraszanie energii
widmo energii
prędkość wahania
Opis:
The scaling of turbulence characteristics such as turbulent fluctuation velocity, turbulent kinetic energy and turbulent energy dissipation rate was investigated in a mechanically agitated vessel 300 mm in inner diameter stirred by a Rushton turbine at high Reynolds numbers in the range 50 000 < Re < 100 000. The hydrodynamics and flow field was measured using 2-D TR PIV. The convective velocity formulas proposed by Antonia et al. (1980) and Van Doorn (1981) were tested. The turbulent energy dissipation rate estimated independently in both radial and axial directions using the one-dimensional approach was not found to be the same in each direction. Using the proposed correction, the values in both directions were found to be close to each other. The relation /(N3·D2) const. was not conclusively confirmed.
Źródło:
Chemical and Process Engineering; 2015, 36, 2; 135-149
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelowanie rozkładu energii kinetycznej burzliwości i jej szybkości dyssypacji podczas wytwarzana zawiesiny lekkiej
Modeling of turbulence kinetic energy distribution and their dissipation rate in mechanically agitated floating suspension of particles
Autorzy:
Kacperski, Ł.
Karcz, J.
Powiązania:
https://bibliotekanauki.pl/articles/2072440.pdf
Data publikacji:
2013
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
zawiesina lekka
modele burzliwości k-ε
k-ω
SST
kinetyczna energia burzliwości i szybkość jej dyssypacji
floating particles suspension
kinetic energy of turbulence and its dissipation rate
k-ε
SST turbulence models
Opis:
Przedstawiono wyniki modelowania numerycznego energii kinetycznej burzliwości i szybkości jej dyssypacji w zbiorniku z mieszadłem do wytwarzania zawiesiny lekkiej. Uzyskano kontury oraz profi le tych wielkości dla burzliwego ruchu płynu w mieszalniku i trzech modeli burzliwości k-ε, k-ω, lub SST. Zidentyfikowano strefy, w których modelowane zmienne przyjmują największe wartości i w których rozpraszanie cząstek ciała stałego jest najbardziej efektywne.
Results of numerical modeling of turbulence kinetic energy and its dissipation rate in mechanically agitated floating particles’ suspension are presented. Contours and profiles of these quantities were found for turbulent fluid flow in an agitated vessel and three turbulence 'models k-ε, k-ω or SST. The agitated vessel zones in which modeled quantities took the greatest values and where the best dispersion of floating particles was obtained were identified.
Źródło:
Inżynieria i Aparatura Chemiczna; 2013, 3; 189--190
0368-0827
Pojawia się w:
Inżynieria i Aparatura Chemiczna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulation of flow and heat transfer in hydromagnetic micropolar fluid between two stretchable disks with viscous dissipation effects
Autorzy:
Ali, K.
Ahmad, S.
Ashraf, M.
Powiązania:
https://bibliotekanauki.pl/articles/279778.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
MHD
micropolar fluid
stretchable disk
viscous dissipation
couple stress
heat transfer rate
Opis:
A study of magnetohydrodynamic (MHD) flow with viscous dissipation and heat transfer in an electrically conducting laminar steady viscous incompressible micropolar fluid between two infinite uniformly stretching disks is presented. The transformed self similar nonlinear ODEs are first linearized using a quasi linearization method and then solved by employing a combination of a direct and an iterative method. The study may be beneficial to flow and thermal control of polymeric processing.
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 2; 633-643
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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