Experimental Modelling of Local Heat Transfer Process for a Gas-liquid System in an Agitated Vessel with the System of A 315 – RT Impellers

The results of the experimental studies of the local heat transfer process for a gas-liquid system in the region of the cylindrical wall of baffled agitated vessel equipped with the system of A 315 (lower) – RT (upper) impellers are presented. Newtonian liquids of different physical properties and air were used as continuous and dispersed phases, respectively. Local heat transfer coefficients were measured using both thermal and electrochemical methods. Distributions of the heat transfer coefficients were described by means of equations (13) – (16) and (17) – (21), separately, for turbulent and transitional ranges of the fluid flow in the agitated vessel. These equations, concerning both coalescing and non-coalescing gas-liquid systems, have no equivalent in the open literature. Moreover, the results for the A 315 – RT impeller system were compared with our previous heat transfer data obtained using CD 6 – RT or RT – RT impeller systems. This work is licensed under a Creative Commons Attribution 4.0 International License

Effect of the eccentric location of propeller or HE 3 impeller on power consumption

Badania miały na celu określenie wpływu niecentrycznego usytuowania mieszadła eR i wysokości słupa cieczy H w zbiorniku na moc mieszania. Mieszalnik o średnicy wewnętrznej D = 0,45 m był napełniany cieczą do wysokości H∈ . Pomiary przeprowadzono dla pięciu różnych pozycji wału w zbiorniku, w zakresie parametru eR ∈ . Ciecz mieszano mieszadłami śmigłowym lub HE 3 wytwarzającymi osiową cyrku lację płynu w zbiorniku. Na podstawie uzyskanych wyników pomiarów, opisanych równaniami (1-3), stwierdzono, że liczba mocy zwiększa się ze wzrostem niecentryczności wału mieszadła eR.The studies of effects of the impeller shaft eccentricity, eR, and liquid he ight in the vessel, H, on power consumption are presented in the paper. The agitated vessel of inner diameter D = 0.45 m was filled with liquid up to the height H&isisin;. The impeller shaft eccentricity varied within a range of eR&isisin;. The axial flow propeller and HE 3 impeller were used for agitation of Newtonian liquid. The results of studies were described by means of Eqs. (1-3). These results show that the power number increases with the increase of the shaft eccentricity eR

Origin and distribution of high fluoride content water in the MGWB no 338 Paczków-Niemodlin

Stężenie fluoru w wodach pitnych jest obiektem zainteresowania wielu ośrodków badawczych na świecie, ponieważ szkodliwy dla ludzi jest nie tylko jego niedobór (poniżej 0,8 mg/l), powodujący próchnicę zębów, ale również nadmiar (powyżej 1,5 mg/l), który może przyczyniać się do rozwoju fluorozy i osteoporozy. W Oddziale Górnośląskim PIG prowadzono badania dotyczące rozprzestrzenienia anomalii fluorowej w wodach neogeńskiego piętra wodonośnego w GZWP nr 338 Paczków Niemodlin. Zawartość fluoru w wodach podziemnych w tym rejonie jest wysoka i sięga od 6 do 11,5 mg/l, przekraczając wartości dopuszczalne dla wód pitnych około 10 razy. Największa anomalia występuje w rejonie Nysy. Badania potwierdziły wzrost zawartości fluoru wraz ze spadkiem rzędnej stropu poziomów wodonośnych. Najwyższe stężenia tego pierwiastka stwierdzono w poziomach zlokalizowanych na rzędnych 30-80 m n.p.m.The problem of fluoride in drinking water is currently the subject of study of many research centres in the world, because not only deficit of fluorine (below 0.8 mg / l), which causes teeth caries, but also its excess (above 1.5 mg / l), which may cause fluorosis and osteoporosis, are harmful to human being. A hydrogeochemical study conducted in the Upper Silesian Branch of the PGI lead to detailed recognition of hydrogeological and chemical conditions as well as the extent of fluoride anomaly in Neogene aquifer water in the Paczków-Niemodlin basin. The fluoride content in groundwater of the basin is high and ranges from 6.0 to 11.5 mg/l, exceeding about 10 times the permissible values for drinking water. The highest concentrations of fluoride are observed in the Nysa region. The investigations confirmed the increase of fluoride content with decreasing altitude of the aquifer top. The highest concentrations are found in the aquifer whose top is situated at 30-80 m a.s.l

Gas hold-up for gasliquid-biophase systems in a bioreactor with the CD 6 impeller

Określono wpływ wybranych parametrów (natężenia przepływu gazu, częstości obrotów mieszadła oraz stężenia sacharozy w układzie) na udział gazu zatrzymanego w cieczy dla układu ciecz-gaz-biofaza. Badania wykonano w mieszalniku o średnicy 0,288 m z mieszadłem CD 6. Wyniki badań opracowano w postaci równania. Stwierdzono, że udział gazu zatrzymanego w cieczy silnie zależy od częstości obrotów mieszadła oraz natężenia przepływu gazu.The studies of different parameters effect (gas flow rate, impeller speed and sucrose concentration) on gas hold-up in the gas-liquid-biophase system are presented in the paper. The measurements were conducted in a vessel of 0.288 m in diameter equipped with the CD 6 impeller. The experimental results were described by the equation. The study shows that gas hold-up strongly depends on the impeller speed and gas flow rate

Modelling of multi-layered groundwater basins; a case study of MGWB No. 338 Paczków-Niemodlin

The objective of this paper is to present the advantages and problems related to the application of a multi-layer model in hydrogeological investigations, exemplified by the Main Groundwater Basin No. 338. The main aquifer in this basin is Neogene, but Quaternary, Cretaceous and Palaeozoic-Proterozic aquifers have also been identified there. Due to the presence of numerous permeable layers, separated by impermeable ones of irregular distribution in the Neogene aquifer, 27 model layers have been distinguished, including 10 water-bearing horizons. A large number of model blocks caused the increase of the computational time, and a large number of layers have lengthened the calibration time of the model. However, anthropogenic or geologic threats to multi-layer structures have justified such a large number of layers, enabling the water balance for the selected part of the basin orfor the selected depth intervals with groundwater of good or bad status

Influence of different factors on momentum transfer in mechanically agitated multiphase systems

A comparative analysis concerning the influence of different factors on momentum transfer in mechanically agitated systems was carried out on the basis of experimental results for solid-liquid, gas-liquid and gas-solid-liquid systems. The effects of the impeller - baffles system geometry, scale of the agitated vessel, type and number of impellers and their off-bottom clearance, as well as physical properties of the multiphase systems on the critical impeller speeds needed to produce suspension or dispersion, power consumption and gas hold-up were analysed and evaluated