scholarly journals Rheological Parameters and Transport Characteristics of Fresh Cement Tailings Backfill Slurry in an Underground Iron Mine

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Chi Zhang ◽  
Yu-Ye Tan ◽  
Kai Zhang ◽  
Chun-Yue Zhang ◽  
Wei-Dong Song
Keyword(s):  
Solid Content ◽  
Rheological Parameters ◽  
Flow State ◽  
Pipeline Transportation ◽  
Filling System ◽  
Iron Mine ◽  
Unclassified Tailings ◽  
Fluent Software ◽  
Resistance Loss ◽  
The Relationship

Pipeline transportation is the key component of the mine filling system. In this study, fresh cement tailing backfill (CTB) slurry made by unclassified tailings from the Daye iron mine is taken as the research object, and its rheological parameters and transport characteristics are studied via laboratory test and FLUENT software. It was found that the relationship curve of the dynamic yield stress, viscosity, and solid content (SC) of CTB slurry fits the law of the H-B model when SC varies between 60% and 68%. However, the relationship curve gradually changes to fit the Bingham mode when SC reaches up to 70%. Numerical simulation results demonstrate that when the SC of CTB slurry exceeds 65%, the static pressure at the pipeline’s outlet begins to distribute symmetrically. At this point, the slurry flow state is relatively stable, and the pipeline resistance loss is positively correlated with SC and flow rate. When SC exceeds 70%, resistance loss begins to increase significantly. The findings of this study can be used to identify the suitable transportation conditions of CTB slurry and provide the theoretical direction for the pipeline transportation design of filling systems in mines.

scholarly journals Utilization of Foaming Technology in Cemented Paste Backfill of High-Mud Superfine Unclassified Tailings

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Jian-wen Zhao ◽  
Xin-min Wang ◽  
Kang Peng ◽  
Shuai Li
Keyword(s):  
Rheological Parameters ◽  
Cemented Paste Backfill ◽  
Pipeline Transportation ◽  
Bleeding Rate ◽  
Three Phase ◽  
Three Phase Flow ◽  
Unclassified Tailings ◽  
Paste Backfill ◽  
Resistance Loss ◽  
Foaming Technology

Due to high-mud content in superfine unclassified tailings (SUT), the viscosity of cemented paste backfill (CPB) is high and its pipeline transportation properties are poor. Foaming technology was introduced to prepare a new three-phase flow backfill (TFB) using a foaming machine. Then the rheological parameters of TFB with different bubble ratio were measured and their pipeline transportation properties were simulated by Fluent. Besides, the simulation results were further verified by a semi-industrial loop test. The results indicate that the optimum ratio of TFB is a cement-sand ratio of 1 : 8, mass concentration of 70%, and bubble ratio of 20%. Compared with CPB, the decrease of bleeding rate, viscosity, and resistance loss of TFB is 27%, 25%, and 30%, respectively. Therefore, foaming technology is an innovative and feasible solution for high-mud CPB in reducing viscosity, decreasing resistance loss, and improving pipeline transporting efficiency.

scholarly journals Design of a Waterborne Polyurethane–Urea Ink for Direct Ink Writing 3D Printing

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3287
Author(s):  
Julen Vadillo ◽  
Izaskun Larraza ◽  
Tamara Calvo-Correas ◽  
Nagore Gabilondo ◽  
Christophe Derail ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
3D Printing ◽  
Soft Segment ◽  
Waterborne Polyurethane ◽  
Solid Content ◽  
Rheological Parameters ◽  
Good Shape ◽  
Physical Gel ◽  
Tan Δ ◽  
The Relationship

In this work, polycaprolactone–polyethylene glycol (PCL–PEG) based waterborne polyurethane–urea (WBPUU) inks have been developed for an extrusion-based 3D printing technology. The WBPUU, synthesized from an optimized ratio of hydrophobic polycaprolactone diol and hydrophilic polyethylene glycol (0.2:0.8) in the soft segment, is able to form a physical gel at low solid contents. WBPUU inks with different solid contents have been synthesized. The rheology of the prepared systems was studied and the WBPUUs were subsequently used in the printing of different pieces to demonstrate the relationship between their rheological properties and their printing viability, establishing an optimal window of compositions for the developed WBPUU based inks. The results showed that the increase in solid content results in more structured inks, presenting a higher storage modulus as well as lower tan δ values, allowing for the improvement of the ink’s shape fidelity. However, an increase in solid content also leads to an increase in the yield point and viscosity, leading to printability limitations. From among all printable systems, the WBPUU with a solid content of 32 wt% is proposed to be the more suitable ink for a successful printing performance, presenting both adequate printability and good shape fidelity, which leads to the realization of a recognizable and accurate 3D construct and an understanding of its relationship with rheological parameters.

Numerical Simulation on Velocity Profiles of Mill Bearing Lubrication

2010 ◽  
Vol 145 ◽  
pp. 282-286
Author(s):  
Qing Xue Huang ◽  
Jian Mei Wang ◽  
Yu Gui Li ◽  
Li Feng Ma ◽  
Chun Jiang Zhao
Keyword(s):  
Cross Section ◽  
Velocity Profiles ◽  
Flow State ◽  
Oil Film ◽  
Velocity Gradients ◽  
Oil Flow ◽  
The Mathematical Model ◽  
The Relationship ◽  
General Velocity ◽  
Oil Film Pressure

No 460 oil-film bearing oil as the dedicated lubricant is regarded as the incompressible Newtonian fluid. To comprehensively analyze the real oil flow state, the mathematical model on velocity profiles, together with its dimensionless equations, is established, and the calculating program is developed to simulate the 3D velocity profiles and velocity gradients at different oil flow layers. The relationship between velocity profiles and the oil film pressure is discussed, and the velocity tendency is consistent with the general velocity profile of wedge cross section. The conclusions are beneficial to the further study on lubricating performances of heavy contact components and to prolong their service lives.

Numerical Simulation of High-Aspect-Ratio Micro-Hole Electroforming with External Magnetic Field

2010 ◽  
Vol 42 ◽  
pp. 13-16
Author(s):  
Wei Li ◽  
Ping Mei Ming ◽  
Wu Ji Jiang ◽  
Yin Ding Lv
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Flow State ◽  
Cathode Electrode ◽  
Micro Hole ◽  
Fluent Software ◽  
The Magnetic Field ◽  
Enhance Mass

In this paper, the influences of applied magnetic field on flow state during electroforming of the high-aspect-ratio (HAR) blind micro-hole were numerically analyzed using the Fluent software. The results showed that, when microelectroforming of nickel without external agitation, three vortexes could form due to the magnetohydrodynamic (MHD) effect within the HAR micro-hole with magnetic field in parallel to cathode-electrode surface, and the flow rate in the micro-hole increased with the increase of the magnetic field and current density. The MHD effect helped to enhance mass transfer during the microelectroforming of HAR microstructures.

scholarly journals Analysis of total suspended solid content based on rain characteristics in the Ciliwung River basin

2020 ◽  
Vol 10 (3) ◽  
pp. 352-363
Author(s):  
Sulistyo Ariebowo Djajusman ◽  
Hadi Susilo Arifin ◽  
Etty Riani
Keyword(s):  
Regression Analysis ◽  
Multiple Regression Analysis ◽  
Multiple Regression ◽  
Correlation Coefficient ◽  
Total Suspended Solid ◽  
Suspended Solid ◽  
Solid Content ◽  
Rainfall Characteristics ◽  
Middle Stream ◽  
The Relationship

Total suspended solid (TSS) is one of the parameters that determines whether or not a body of water is polluted. One factor that influences the amount of TSS content is the characteristic of rainfall in an area. Purpose of this study was to determine the relationship between the effect of rainfall characteristics and TSS content in Ciliwung River. Multiple regression analysis was used for analytical method.  Results of multiple regression analysis showed that the correlation coefficient (adjusted R2) for the factors of rainfall, discharge and sediment show a low correlation to changes the content of TSS in Ciliwung River. The value of each correlation coefficient in the upstream, middle, and downstream of Ciliwung River are 0.21, 0.31, and 0.09 respectively. According to the F test, rainfall, discharge and sediment  were significantly affect TSS content in the upstream and middle stream.  Based on t test, it is known that only rainfall affect TSS content in the upstream and midlle stream.

Development of New Models to Determine the Rheological Parameters of Water-based Drilling Fluid Using Artificial Intelligence

2021 ◽  
Author(s):  
Farqad Hadi ◽  
Ali Noori ◽  
Hussein Hussein ◽  
Ameer Khudhair
Keyword(s):  
Rheological Properties ◽  
High Performance ◽  
Drilling Fluid ◽  
Gel Strength ◽  
Solid Content ◽  
Rheological Parameters ◽  
Water Based ◽  
Fluid Properties ◽  
Drilling Operations ◽  
Marsh Funnel

Abstract It is well known that drilling fluid is a key parameter for optimizing drilling operations, cleaning the hole, and managing the rig hydraulics and margins of surge and swab pressures. Although the experimental works present valid and reliable results, they are expensive and time consuming. On the other hand, continuous and regular determination of the rheological mud properties can perform its essential functions during well construction. More uncertainties in planning the drilling fluid properties meant that more challenges may be exposed during drilling operations. This study presents two predictive techniques, multiple regression analysis (MRA) and artificial neural networks (ANNs), to determine the rheological properties of water-based drilling fluid based on other simple measurable properties. While mud density (MW), marsh funnel (MF), and solid% are key input parameters in this study, the output functions or models are plastic viscosity (PV), yield point (YP), apparent viscosity (AV), and gel strength. The prediction methods were demonstrated by means of a field case in eastern Iraq, using datasets from daily drilling reports of two wells in addition to the laboratory measurements. To test the performance ability of the developed models, two error-based metrics (determination coefficient R2 and root mean square error RMSE) have been used in this study. The current results of this study support the evidence that MW, MF, and solid% are consistent indexes for the prediction of rheological properties. Both mud density and solid content have a relative-significant effect on increasing PV, YP, AV, and gel strength. However, a scattering around each fit curve is observed which proved that one rheological property alone is not sufficient to estimate other properties. The results also reveal that both MRA and ANN are conservative in estimating the fluid rheological properties, but ANN is more precise than MRA. Eight empirical mathematical models with high performance capacity have been developed in this study to determine the rheological fluid properties based on simple and quick equipment as mud balance and marsh funnel. This study presents cost-effective models to determine the rheological fluid properties for future well planning in Iraqi oil fields.

Spray atomization simulation of bamboo kraft black liquor with high solid content at splash-plate nozzle

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 6599-6612
Author(s):  
Yongjian Xu ◽  
Shenglin Chen ◽  
Xin Du ◽  
Xiaopeng Yue
Keyword(s):  
Paper Industry ◽  
Black Liquor ◽  
Injection Pressure ◽  
Development Trend ◽  
Solid Content ◽  
Nozzle Diameter ◽  
Spray Atomization ◽  
Kraft Black Liquor ◽  
Fluent Software ◽  
Solids Content

Increasing the solids content of pulping black liquor burned in a furnace is a development trend of the alkali recovery system in the pulp and paper industry. However, the viscosity of kraft black liquor increases exponentially with an increase in solids content, especially in the case of non-wood pulping black liquor, such as bamboo. This brings great difficulties to the pulping system and atomization of black liquor at the splash-plate nozzle, which is a complete atomization unit constituted of a splash nozzle and a splash plate. To obtain instructive results for industry, a simulation of the atomization process was made using Fluent software for the bamboo kraft black liquor with solids contents of 70 wt% and 80 wt%, which flowed through splash nozzles with the diameter of 22 or 20 mm. The studies were conducted on the distribution of flow field in the nozzle and atomization region through changing the injection pressure and nozzle diameter. The variation of atomization characteristic parameters, such as liquid film thickness, and breakup length, were elucidated. The results reveal the relationship between spray atomization with injection pressure and nozzle diameter, which provides a theoretical basis for improving the concentration of black liquor entering alkali recovery in the future.

Rheological Characteristics of Juniperus drupacea Fruit Juice (pekmez) Concentrated by Boiling

2008 ◽  
Vol 14 (4) ◽  
pp. 321-328 ◽  
Author(s):  
M. Akbulut ◽  
H. Çoklar ◽  
G. Özen
Keyword(s):  
Flow Characteristics ◽  
Shear Thickening ◽  
Solid Content ◽  
Soluble Solids ◽  
Effect Of Temperature ◽  
Coefficient Of Determination ◽  
Rheological Parameters ◽  
Soluble Solid Content ◽  
Rotational Viscometer ◽  
Soluble Solid

Rheological parameters of Juniperus drupacea fruit pekmez were evaluated using a rotational viscometer at 10, 20, 30, 40, and 50 °C and at concentrations of 62.8, 68.9, 72.0, and 75.2% total soluble solids. The flow characteristics of Juniperus drupacea fruit pekmez were described by the power law and Herschel—Bulkley models. The Herschel—Bulkley model was found to be the best to describe the rheological property with the coefficient of determination higher than 0.993. Juniperus drupacea pekmez exhibited a time-independent shear thickening behavior. The effect of temperature on viscosity can be described by means of an Arrhenius equation. Depending on the soluble solid contents, the activation energies for flow of diluted samples vary from 78.23 to 60.38 kJ/mol. The effect of soluble solids on viscosity can be described by an exponential equation. Experimental data were fitted to several models in order to describe the effect of temperature and soluble solid content. The combined effect of temperature and soluble solid content on viscosity was also formulated.

P6486Flow state, gradients and anatomopathological valvular calcification: influence in aortic stenosis surgical outcomes

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
J T Museli ◽  
L Zambruno ◽  
N Coria ◽  
G Giunta ◽  
J F Salmo ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Aortic Stenosis ◽  
Ejection Fraction ◽  
Low Flow ◽  
P Value ◽  
Flow State ◽  
Normal Flow ◽  
Perioperative Mortality ◽  
High Gradient ◽  
The Relationship

Abstract Introduction Aortic stenosis (AS) patients are heterogeneous. The relationship between stenosis severity, transvalvular flow state and gradients is conflictive and non-linear. Objective To evaluate the relationship between transvalvular flow state and gradients with the anatomopathological aortic valve characteristics and perioperative morbimortality among patients (pt) submitted to aortic valve replacement (AVR). Methods We analyzed 516 pt with symptomatic severe AS (effective valve area <1 cm2) with preserved left ventricular ejection fraction (>50%) submitted to AVR. Perioperative mortality and a combined endpoint (death, low cardiac output syndrome and acute renal injury) were analyzed dividing the population by transvalvular flow (35 ml/m2) and mean gradient (40 mmHg), both measured by echocardiography. A morphologic evaluation of 383 operatively excised native cardiac valves was performed. Valvular thickening and calcification were categorized in mild, moderate and severe. Results Male subjects represented 52.9% (283 pt). Mean age were 69±11.5 years. Pt showed a mean ejection fraction of 61±4.8%, the peak gradient was 86.2±24 mmHg, and mean gradient was 53±18 mmHg. Cardiac low output syndrome (normal flow (NF) – 14%, low flow (LF) – 23%; p<0,02), IABP (NF 1,8%, LF 6%, p<0,02) and perioperative mortality (NF 2,7%, LF 7%, p<0,02) were more frequent in low flow pt (185 – 35%). Bicuspid valves represented 24.5% of the whole population. Bicuspid patients were younger 64±9 vs 73±12 years (p<0.05) and had more moderate–severe calcification (MSC) 93.4% vs 75.6% (p<0.05). No difference was found in moderate -severe thickening (MSTh) and MSC when analyzing the population by flow (35 ml/m2). On the contrary, low gradient pt (<40mmHg) had lower MSC and MSTh. (Table) Finally, 4 groups were considered: normal flow–high gradient NFHG (52.2%), normal flow–low gradient NFLG (12%), low flow–high gradient LFHG (25.5%) and low flow–low gradient LFLG (10.1%). A trend toward more perioperative events was seen in the LF-LG group despite less calcified and thickened valves. (Figure) Table 1 Normal Flow Low Flow P value Normal gradient Low gradient P value M-S thickening 143 (58.1%) 80 (58.3%) NS 186 (62.4%) 37 (43.5%) 0.0018 M-S calcification 195 (79.2%) 119 (86.8%) NS 263 (88.2%) 51 (60%) <0.05 Bicuspid valve 62 (25%) 32 (23%) NS 62 (25.2%) 32 (23.3%) NS M-S: Moderate-Severe. Figure 1 Conclusions In our population of severe symptomatic AS with preserved ejection fraction submitted to AVR, low gradient pts had less calcified and thickened valves. LFLG pts presented a trend towards more perioperative events despite having less valvular calcification.

scholarly journals Detection of the Flow State for a Centrifugal Pump Based on Vibration

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3066 ◽  
Author(s):  
Jiaxing Lu ◽  
Xiaobing Liu ◽  
Yongzhong Zeng ◽  
Baoshan Zhu ◽  
Bo Hu ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Great Influence ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Flow Instabilities ◽  
Flow State ◽  
Unstable Flow ◽  
Vibration Signals ◽  
State Identification ◽  
The Relationship

A combined numerical and experimental method study was performed to detect the inner flow state for a type of centrifugal pump. It was found that the inlet attack angles of blades in an impeller have a great influence on the flow instabilities in a centrifugal pump. The mechanism of the rotating stall in the impeller channel was explained. Meanwhile, flow state identification with vibration (FSIV) was proposed to detect the flow instabilities in a centrifugal pump. The relationship between the external vibration and the inner flow state has been established by FSIV. The characteristics and mechanism of the vibration produced by the flow instabilities in a centrifugal pump were investigated. It was found that the hump, the rotating stall, the backflow, the occurrence of unstable flow, and the cavitation in the centrifugal pump can be effectively detected by applying the vibration signals, which helps to obtain safe and steady operating conditions for the system.

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