Effects of Bath Depth and Eccentricity on Mixing Phenomena in Shaking Ladle

2014 ◽  
Vol 0 (0) ◽  
Author(s):  
Shanqiang Ni ◽  
Haijuan Wang ◽  
Jun Zhang ◽  
Shaojun Chu
Keyword(s):  
Electrical Conductivity ◽  
Deep Water ◽  
Mixing Time ◽  
Mixing Efficiency ◽  
Water Type ◽  
Medium Carbon ◽  
Bath Depth ◽  
Flow Phenomena ◽  
Industry Practice ◽  
Metallurgical Processes

AbstractWater modeling experiments were carried out to investigate the mixing time and fluid flow phenomena in a shaking ladle, which is widely used in production of low and medium carbon ferromanganese and ferrochrome and also other metallurgical processes. Mixing time was determined by electrical conductivity probe method. A new concept of CSS-MT (critical shaking speed based on mixing time) was defined, which was different from the previous CSS-WH (critical shaking speed based on wave height). And the influences of bath depth and eccentricity on the CSS-MT were studied. The results showed that the mixing behaviors in shaking ladle can be categorized into shallow water type and deep water type, and the mixing efficiency of the former is poor and should be avoided in the industry practice. For the deep water type, the CSS-MT increases with increasing of bath depth and is approximately 15 rpm greater than the CSS-WH obtained from Ishii’s empirical formula. A larger eccentricity is helpful to decrease the critical shaking speed within certain limitations which is 30 mm; however, it is useless for increasing the eccentricity when it is above the limitation.

Spatial distribution and hydrochemistry of springs and seepage springs in the Lubuska Upland of western Poland

2013 ◽  
Vol 45 (3) ◽  
pp. 379-390 ◽  
Author(s):  
Anna Maria Szczucińska
Keyword(s):  
Electrical Conductivity ◽  
Spatial Distribution ◽  
Trace Metals ◽  
Calcium Ions ◽  
Major Part ◽  
Major Ions ◽  
Water Type ◽  
Average Temperature ◽  
Last Glaciation ◽  
River Valleys

The major part of the Polish Plain (central Europe) was shaped during the last glaciation and so far has been considered to be poor in groundwater outflows. The present study aimed to map the groundwater outflows and to analyse their water properties in the Lubuska Upland, western Polish Plain. The mapping of the groundwater outflows was supplemented by hydrochemical analyses (major ions and trace metals) of selected outflows. Altogether, approximately 600 groundwater outflows were recorded, of which 45% were springs. The outflow water discharges ranged from 0.001 to 45 L s−1. Most of them were located at the bottom of the slopes of river valleys. The water was neutral (pH 6.9 to 8.11), with electrical conductivity from 261 to 652 μS cm−1 and average temperature ~10 °C. The most common water type was dominated by bicarbonate, sulphates and calcium ions. The waters often exceeded the quality limits for total Fe and Mn2+. This study revealed that groundwater outflows are a common feature of the areas shaped by former glaciations and are most likely supplied by shallow aquifers.

scholarly journals Effect of Bottom Blowing Mode on Fluid Flow and Mixing Behavior in Converter

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 117
Author(s):  
Jiankun Sun ◽  
Jiangshan Zhang ◽  
Wenhui Lin ◽  
Xiaoming Feng ◽  
Qing Liu
Keyword(s):  
Refractory Lining ◽  
Mixing Time ◽  
Diffusion Path ◽  
Tracer Diffusion ◽  
Mixing Efficiency ◽  
Molten Bath ◽  
Local Flow ◽  
Average Value ◽  
Type Mode ◽  
Bottom Blowing

Bottom blowing agitation plays a crucial role in improving the reaction kinetics condition of molten bath during the steelmaking process. Herein, the influence of bottom blowing mode on the flow and mixing characteristics of molten bath and the abrasion characteristics of refractory lining in a 6:1 scaled-down model of a 100 t converter were investigated using physical and numerical simulations together. Eight bottom blowing modes were designed (uniform, three-point linear co-direction, three-point linear unco-direction, two-point linear, circumferential linear, A-type, V-type, and triangle alternating). The results indicated that bottom blowing mode has a significant effect on the local flow field at the inner ring of bottom tuyeres, the velocity interval distribution, and the turbulent kinetic energy, which in turn determines the tracer diffusion path and rate as well the mixing time of molten bath. Reasonable non-uniform bottom blowing modes promote the interaction between the various stirring sub-zones of the molten bath. Among them, the three-point linear co-direction mode and A-type mode have the highest mixing efficiency under the conditions of bottom blowing and combined blowing, respectively, which is superior to the uniform mode. In addition, the bottom blowing mode changed the location and degree of abrasion of the refractory lining, and the total abrasion of the non-uniform mode was reduced. The average value and fluctuation degree of integral wall shear stress for the A-type mode were minimal.

scholarly journals IRRIGAÇÃO DE PORTA-ENXERTOS CÍTRICOS COM ÁGUAS SALINAS

Irriga ◽  
2006 ◽  
Vol 11 (3) ◽  
pp. 428-440
Author(s):  
Tales Miler Soares ◽  
Sergio Nascimento Duarte ◽  
Cristiano Nascimento Duarte ◽  
Christiano César Dibbern Graf ◽  
Marcelo Zanetti ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Plant Growth ◽  
Natural Water ◽  
Saline Water ◽  
Calcium Nitrate ◽  
Sao Paulo ◽  
Water Type ◽  
São Paulo ◽  
New Production ◽  
Saline Waters

IRRIGAÇÃO DE PORTA-ENXERTOS CÍTRICOS COM ÁGUAS SALINAS  Tales Miler Soares1; Sergio Nascimento Duarte1; Christiano César Dibbern Graf2; Marcelo Zanetti2; Silvio Sandoval Zocchi31Departamento de Engenharia Rural, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, SP, [email protected] Mudas, Conchal,  SP3Departamento de Ciências Exatas, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, SP  1 RESUMO Avaliar o desenvolvimento dos porta-enxertos limoeiro ‘Cravo’, tangerineira ‘Cleópatra’ e citrumeleiro ‘Swingle’, irrigados com águas salinas, mensurando se a aplicação de Ca(NO3)2 mitiga eventuais efeitos de íons fitotóxicos, foi objetivo do presente trabalho, conduzido sob ambiente protegido, em Rio Claro-SP. Investigou-se três qualidades de água: água natural (CEa= 1,19 dS m-1), explorada de poço tubular profundo, água dessalinizada (CEa= 0,02 dS m-1), obtida mediante osmose reversa da água natural, e água residual (CEa= 2,11 dS m-1), sub-produto da dessalinização. Os níveis de Ca(NO3)2 avaliados foram 0 e 2,105 g L-1. Averiguando-se os parâmetros usuais do crescimento vegetal, não foram observadas diferenças estatísticas, entre os tratamentos, decorrentes da qualidade da água, embora se tenha registrado que esta contribuiu para o aumento da salinização do substrato, ultrapassando, inclusive, o valor da salinidade limiar (CEes= 1,4 dS m-1) reconhecido para os citros. A adição de Ca(NO3)2 não incrementou o desenvolvimento, atuando negativamente no crescimento inicial das raízes e do caule. O curto período necessário ao crescimento dos porta-enxertos, proporcionado pelo atual sistema de produção, associado às irrigações freqüentes e suas frações de lixiviação podem ter restringido efeitos negativos das águas salinas investigadas. UNITERMOS: Citrus, salinidade, condutividade elétrica, substrato.  SOARES, T.M.; DUARTE, S.N.; GRAF, C.C.D.; ZANETTI, M.; ZOCCHI, S.S.       CITRUS ROOTSTOCKS IRRIGATION WITH SALINE WATER  2 ABSTRACT This research aimed to evaluate the growth of three citrus rootstocks (‘Rangpur’ lime, ‘Cleopatra’ mandarin and ‘Swingle’ citrumelo) irrigated with saline waters, under greenhouse conditions, in order to measure if calcium nitrate mitigates their toxic effects. Three water qualities were investigated: natural water (ECw= 1,19 dS m-1), obtained from a deep tubular well, desalinated water (ECw= 0,02 dS m-1), obtained by reverse osmosis from the natural water, and reject water (ECw= 2,11 dS m-1), resultant from the desalination process. Two Ca(NO3)2 levels were evaluated: 0 and 2,105 g L-1. Usual parameters for plant growth analysis were measured. According to Tukey’s test (5% probability), water quality did not affect rootstocks development, although the water type have contributed to increase the electrical conductivity of substrate saturation extract (ECs) along the experimental period, surpassing the salinity threshold value (ECs = 1,4 dS m-1) reported for citrus. The Ca(NO3)2 addition did not increase the plant growth, but negatively affected the first evaluations of root and stem diameter development. The short time necessary to rootstocks growth provided by new production system, associated to the frequent irrigations and its leaching fractions possible may have restricted the negative effects of saline waters. KEYWORDS: Citrus, salinity, electrical conductivity, substrate.  

scholarly journals Hydrochemistry of Groundwater in Northeast Part of Anbar Governorate – West of Iraq

2019 ◽  
Vol 16 (1) ◽  
pp. 0088
Author(s):  
Hussein Ilaibi Zamil Al-Sudani
Keyword(s):  
Electrical Conductivity ◽  
Groundwater Quality ◽  
Total Dissolved Solids ◽  
Water Type ◽  
Hydrochemical Parameters ◽  
Dissolved Solids ◽  
Drinking Purposes ◽  
Groundwater Samples ◽  
Geological Formation ◽  
Continental Origin

A groundwater quality assessment has been carried out in northeast part of Anbar governorate in western Iraq. We analyzed hydrochemical parameters such as pH, electrical conductivity, total dissolved solids presence of ions to describe groundwater quality. The study area has the only confined aquifer within the geological formation extended in area. Values of groundwater hydrochemical parameters were ranged from (7) to (7.9) for ph, (1599) to (6800) µmhos/cm for electrical conductivity (EC) and (1048) to (4446) mg/l for total dissolved solids (TDS). The origins and types of groundwater in the area were of marine origin and MgCl2 water type while only (6) samples were of continental origin and Na2SO4 water type. Groundwater utilization indicated that it can't be used for drinking purposes, while few groundwater wells can be used for agricultural and (33) groundwater samples can be used for animal purposes. However, the nature of the soil in the area and the depth of the groundwater qualified water for agricultural uses in significant and wide ranges.

scholarly journals The Influence of Non-Engineered Municipal Landfills on Groundwater Chemistry and Quality in Bloemfontein, South Africa

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5599
Author(s):  
Rinae Makhadi ◽  
Saheed A. Oke ◽  
Olusola O. Ololade
Keyword(s):  
South Africa ◽  
Water Quality ◽  
Electrical Conductivity ◽  
High Salinity ◽  
Total Coliform ◽  
Landfill Site ◽  
Water Type ◽  
Permissible Limits ◽  
Salinity Hazard ◽  
Landfill Sites

This study assessed the groundwater quality around two municipal solid waste landfill sites, in the city of Bloemfontein, Free State Province, South Africa. The two landfill sites are located in two contrasting geological terrains, with both lacking some basic facilities found in a well-designed landfill. A total of eight groundwater samples were collected from pollution monitoring boreholes near the two landfill sites, with five samples representing the northern landfill site and three samples representing the southern landfill site. The samples were collected in the autumn and winter seasons to assess any possible seasonal variations. They were analysed for physicochemical (pH, electrical conductivity (EC), total dissolve solids (TDS), chemical oxygen demand (COD) and total organic carbon (TOC)) and microbiological parameters (Escherichia coli, total coliform). The results of the analysis showed that the waters from both landfills were generally dominated by Ca, Mg, SO4, and HCO3 ions. Some of the major anions and cations in the water samples were above the South African National Standard (SANS241:2015) and World Health Organisation (WHO) permissible limits for drinking water. Majority of the boreholes had total dissolved solids and electrical conductivity values exceeding the SANS 241:2015 and WHO permissible limits. Piper trilinear plots for the two landfill sites showed that Ca(Mg)HCO3 water type predominates, but Ca(Mg)SO4 and Ca(Mg)Cl were also found. These water types were further confirmed with expanded Durov diagrams, indicating that that the boreholes represented a water type that is seldom found which is undergoing ion exchange, typical of sulphate contamination. From the SAR diagrams, boreholes in the northern landfill site had a high salinity hazard with only one borehole in the southern landfill site having a high salinity hazard. The geology was found to play a significant role in the distribution of contaminants into the groundwater systems in the study area. The study concluded that the northern landfill site had a poorer water quality in comparison to the southern landfill site based on the analysed physicochemical parameters. However, the southern landfill site showed significant microbial contamination, due to the elevated amount of E. coli and total coliform concentrations. The high permeability of the weathered dolerites in the northern landfill site might have enabled the percolation of contaminants into the groundwater resulting in the poorer water quality.

Reliability Based Deep Water Spool Piece Design

2013 ◽  
Author(s):  
Naresh Juluri ◽  
Elie Dib ◽  
Sherif el-Gebaly ◽  
Philip Cooper
Keyword(s):  
Monte Carlo Simulation ◽  
High Pressure ◽  
Monte Carlo ◽  
Deep Water ◽  
Square Root ◽  
Bending Moments ◽  
Industry Practice ◽  
Fabrication Tolerances ◽  
Outside Diameter ◽  
A Current

Long spools are often required to absorb the end expansion of deep water high pressure and high temperature flowlines. These spools typically have significant metrology and fabrication tolerances. Metrology and spool fabrication tolerances lead to misalignments at the connector hub face. Residual loads then arise from spool deformation due to the installation forces that are required to match-up the connector faces. It is a current industry practice to design the spools for multiple independent tolerances at extreme limits in all directions. Previous project experience shows that the Algebraic Sum (AS) combination of multiple independent tolerances at extreme limits may result in large spools where the probability of occurrence of these tolerances at extreme limits is quite low. The use of less conservative SRSS (square root of sum of squares) combination has been suggested in this paper as an alternative to the Algebraic Sum combination. Due to the large number of misalignment components, the probability of exceeding the loads in the spool and at the connector obtained by the SRSS method is small and is within the applicable failure probabilities defined in DNV-OS-F101. The SRSS method is demonstrated in this paper by using a Monte Carlo simulation. Five different spools have been analysed to demonstrate the suitability of using SRSS misalignments when the spools are designed to DNV-OS-F101. The spools considered include 10″, 16″ and 20″ outside diameter spools to represent different sizes at different loading combinations. Maximum bending moments in the spool and maximum moments at the connector have been considered to check the SRSS feasibility. The results indicate that it is acceptable to use SRSS misalignments as an alternative to AS misalignments. Considering SRSS misalignments in preference to AS leads to reduced spool size and reduced loadings on connectors.

scholarly journals Glacial Meltwater Identification in the Amundsen Sea

2017 ◽  
Vol 47 (4) ◽  
pp. 933-954 ◽  
Author(s):  
Louise C. Biddle ◽  
Karen J. Heywood ◽  
Jan Kaiser ◽  
Adrian Jenkins
Keyword(s):  
Dissolved Oxygen ◽  
Deep Water ◽  
Ocean Model ◽  
Water Type ◽  
Ice Shelf ◽  
Amundsen Sea ◽  
Glacial Meltwater ◽  
Circumpolar Deep Water ◽  
Water Characteristics ◽  
Multiparameter Analysis

AbstractPine Island Ice Shelf, in the Amundsen Sea, is losing mass because of warm ocean waters melting the ice from below. Tracing meltwater pathways from ice shelves is important for identifying the regions most affected by the increased input of this water type. Here, optimum multiparameter analysis is used to deduce glacial meltwater fractions from water mass characteristics (temperature, salinity, and dissolved oxygen concentrations), collected during a ship-based campaign in the eastern Amundsen Sea in February–March 2014. Using a one-dimensional ocean model, processes such as variability in the characteristics of the source water masses on shelf and biological productivity/respiration are shown to affect the calculated apparent meltwater fractions. These processes can result in a false meltwater signature, creating misleading apparent glacial meltwater pathways. An alternative glacial meltwater calculation is suggested, using a pseudo–Circumpolar Deep Water endpoint and using an artificial increase in uncertainty of the dissolved oxygen measurements. The pseudo–Circumpolar Deep Water characteristics are affected by the under ice shelf bathymetry. The glacial meltwater fractions reveal a pathway for 2014 meltwater leading to the west of Pine Island Ice Shelf, along the coastline.

scholarly journals CFD Modelling of Global Mixing Parameters in a Peirce-Smith Converter with Comparison to Physical Modelling

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
Deside K Chibwe ◽  
Guven Akdogan ◽  
Chris Aldrich ◽  
Rauf H Eric
Keyword(s):  
Flow Rate ◽  
Volume Fraction ◽  
Mixing Time ◽  
Volumetric Flow Rate ◽  
Numerical Code ◽  
Mixing Efficiency ◽  
Phase System ◽  
Cfd Modelling ◽  
Cold Model ◽  
Peirce Smith Converter

The flow pattern and mixing in an industrial Peirce-Smith converter (PSC) has been experimentally and numerically studied using cold model simulations. The effects of air volumetric flow rate and presence of overlaying slag phase on matte on the flow structure and mixing were investigated. The 2-D and 3-D simulations of the three phase system were carried out using volume of fluid (VOF) and realizable k - ɛ turbulence model to account for the multiphase and turbulence nature of the flow respectively. These models were implemented using commercial Computational Fluid Dynamics (CFD) numerical code FLUENT. The cold model for physical simulations was a 1:5 horizontal cylindrical container made of Perspex with seven tuyeres on one side of the cylinder typifying a Peirce-Smith converter. Compressed air was blown into the cylinder through the tuyeres, simulating air or oxygen enriched air injection into the PSC. The matte and slag phases were simulated with water and kerosene respectively in this study. The influence of varying blowing conditions and simulated slag quantities on the bulk mixing was studied with five different air volumetric flow rates and five levels of simulated slag thickness. Mixing time results were evaluated in terms of total specific mixing power and two mixing time correlations were proposed for estimating mixing times in the model of PSC for low slag and high slag volumes. Both numerical and experimental simulations were in good agreement to predict the variation characteristics of the system in relation to global flow field variables set up in the converter through mathematical calculation of relevant integrated quantities of turbulence, Volume Fraction (VF) and velocity magnitudes. The findings revealed that both air volumetric flow rate and presence of the overlaying slag layer have profound effects on the mixing efficiency of the converter.

scholarly journals Analysis of the mixing efficiency of the components of the iron-phosphate mixture in the dry state

2021 ◽  
Vol 1,2021 (1,2021(126)) ◽  
pp. 23-27
Author(s):  
Selyverstov Vadim ◽  
Dotsenko Yurii
Keyword(s):  
Mixing Time ◽  
Experimental Studies ◽  
Iron Phosphate ◽  
Original Method ◽  
Cold Hardening ◽  
Mixing Efficiency ◽  
Experiment Research ◽  
Metal Component ◽  
Dispersed Particles ◽  
Urgent Task

The results of researches of influence of time of mixing of initial components in a dry condition on degree of assimilation of iron-containing component of forming and core iron-phosphate cold-hardening mixes are presented. The percentage of assimilation of the dispersed iron-containing component after each minute of mixing in laboratory runners with a total mixing time of 15 minutes was determined experimentally. Using the original method of particle separation, under the microscope were separated scale particles that were not assimilated (not distributed on the surface of the sand), and weighed them. The dependences of the degree of assimilation of the metal component of the iron-phosphate mixture on the mixing time at different initial contents are obtained. It is shown that the highest degree of absorption of the iron-containing component of iron-phosphate mixtures is achieved by mixing the components of the mixture for the first four to five minutes. Then this figure begins to decrease as the grains begin to collapse under the action of the rolls of the runners, and the forces of electrostatic interaction between the surfaces of the grains and the dispersion medium are reduced compared to the forces of mutual gravity between the dispersed particles of iron-containing component of the mixture. Based on the analysis of theoretical positions and the results of experimental studies, the assumption is made about the possibility of adjusting the conditions and parameters of solidification of phosphate binder systems, in particular using iron-containing filler of a certain dispersion and mixing the components in the dry state for some time. It is known that for mixing the components and assimilation of the required part of the iron-containing component of the mixture uses a significant amount of energy (depending on the type of unit used). To reduce the energy consumption of this process, the urgent task is to determine the degree of assimilation of the iron-containing component of phosphate cold-hardening mixtures in their manufacture by mixing the components in the dry state. Keywords: iron-phosphate cold-hardening mixture, mixing in the dry state, interaction, adhesion, experiment, research, dependence

scholarly journals Modeling of mixing for stirred bioreactors: 3. Mixing time for aerated simulated broths

2002 ◽  
Vol 56 (12) ◽  
pp. 506-513 ◽  
Author(s):  
Dan Cascaval ◽  
Corneliu Oniscu ◽  
Anca-Irina Galaction ◽  
Fiorina Ungureanu
Keyword(s):  
Flow Rate ◽  
Rotation Speed ◽  
Mixing Time ◽  
Volumetric Flow Rate ◽  
Mixing Efficiency ◽  
Complex Flow ◽  
Average Deviation ◽  
Stirred Bioreactor ◽  
Stirred Bioreactors ◽  
Turbine Impeller

This paper presents the experiments on mixing efficiency for aerated media for a laboratory stirred bioreactor with a double turbine impeller. The effects of stirrer rotation speed, air volumetric flow rate and stirrer position on the shaft on mixing time for aerated water and simulated broths (CMCNa solutions) were analyzed. Compared to non-aerated broths, the results indicated that the variation of mixing time with the considered parameters is very different, due to the complex flow mechanism of the gas-liquid dispersion, a mechanism which is changed by changing the broth properties or fermentation conditions. Using the Statistics Toolbox of MATLAB some correlations between the mixing time and rotation speed, air volumetric flow rate and stirrer position on the shaft were established. The proposed equations agree well with the experiments, the average deviation being ?9.02%.

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