scholarly journals Numerical Modeling of the Conductivity of the Particle Monolayer with Reduced Size

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Yuxuan Liu ◽  
Jiandong Wang ◽  
Jianchun Guo ◽  
Haiyan Zhu ◽  
Jie Zeng
Keyword(s):  
Particle Size ◽  
Network Optimization ◽  
Fracture Network ◽  
Analytical Models ◽  
Elastic Parameters ◽  
Conductivity Variation ◽  
Hydraulic Fracture Network ◽  
Computational Fluid Dynamics Cfd ◽  
Particle Monolayer ◽  
Proppant Embedment

Fractures filled with a proppant monolayer play an important role in the hydraulic fracture network. Predicting the conductivity of these fractures is the basis of fracture network optimization. However, little attention has been paid to the conductivity of the proppant monolayer. The change of conductivity under various conditions is currently not fully understood. Therefore, in this paper, the conductivity variation under different conditions are simulated. The reduction of particle size was calculated by existing analytical models. The permeability variation was calculated through computational fluid dynamics (CFD) combined with COMSOL Multiphysics. The controlling factors of conductivity under a proppant monolayer were identified. Simulation results indicate that elastic parameters, closure pressure, and proppant distribution have significant influence on conductivity, while creep parameters, such as rock viscosity and time, have limited influence on conductivity. Moreover, the changes in permeability, porosity, and tortuosity with variation of embedment were analyzed. Results indicated that with an increase in embedment, the permeability and porosity decrease as expected. The main reduction (nearly half) emerges in the first 20% of proppant embedment. Furthermore, the permeability of a single particle deviates largely from the prediction of Carman-Kozeny (CK) equation. The tortuosity of proppant particle increases with a decrease in particle size due to embedment. A modification of the Carman-Kozeny equation is proposed to address this influence.

scholarly journals Population Balance Application in TiO2 Particle Deagglomeration Process Modeling

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3523
Author(s):  
Radosław Krzosa ◽  
Łukasz Makowski ◽  
Wojciech Orciuch ◽  
Radosław Adamek
Keyword(s):  
Particle Size ◽  
Titanium Dioxide ◽  
Mechanistic Model ◽  
Population Balance ◽  
Tio2 Particle ◽  
Application Process ◽  
Titanium Dioxide Powder ◽  
Dioxide Powder ◽  
Computational Fluid Dynamics Cfd ◽  
Hydrodynamic Stresses

The deagglomeration of titanium-dioxide powder in water suspension performed in a stirring tank was investigated. Owing to the widespread applications of the deagglomeration process and titanium dioxide powder, new, more efficient devices and methods of predicting the process result are highly needed. A brief literature review of the application process, the device used, and process mechanism is presented herein. In the experiments, deagglomeration of the titanium dioxide suspension was performed. The change in particle size distribution in time was investigated for different impeller geometries and rotational speeds. The modification of impeller geometry allowed the improvement of the process of solid particle breakage. In the modelling part, numerical simulations of the chosen impeller geometries were performed using computational-fluid-dynamics (CFD) methods whereby the flow field, hydrodynamic stresses, and other useful parameters were calculated. Finally, based on the simulation results, the population-balance with a mechanistic model of suspension flow was developed. Model predictions of the change in particle size showed good agreement with the experimental data. Using the presented method in the process design allowed the prediction of the product size and the comparison of the efficiency of different impeller geometries.

scholarly journals Experimental Investigation of Water-Sand Mixed Fluid Initiation and Migration in Filling Fracture Network during Water Inrush

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Bin Yang ◽  
Tianhong Yang
Keyword(s):  
Particle Size ◽  
Critical Velocity ◽  
Network Flow ◽  
Water Inrush ◽  
Functional Relation ◽  
Flow Characteristics ◽  
Fracture Network ◽  
Nonlinear Flow ◽  
Two Phase ◽  
And Migration

For water inrush induced by fracture network flow, the critical velocity of the incipient motion of sand particles was obtained, and the functional relation between critical velocity and particle size was established through a series of tests on the nonlinear flow characteristics of a filling fracture network. The influence of the particle size distribution, hydrodynamic force, and geometric features of the fracture network on the characteristics of particle loss; distribution laws; and water-sand, two-phase migration was also explored. Moreover, the interactions amongst water, movable particles, the surface of the skeleton, and fracture walls, and the formation mechanism of the flow channel were qualitatively analyzed. In addition, the change rules of the mass loss characteristics and porosity of the samples with time were tested successfully. The calculation methods of the permeability and non-Darcy factor of the filling fracture network were also determined.

scholarly journals Analysis of multi-factor coupling effect on hydraulic fracture network in shale reservoirs

2015 ◽  
Vol 2 (2-3) ◽  
pp. 162-166 ◽  
Author(s):  
Yuzhang Liu ◽  
Nailing Xiu ◽  
Yunhong Ding ◽  
Xin Wang ◽  
Yongjun Lu ◽  
...  
Keyword(s):  
Hydraulic Fracture ◽  
Coupling Effect ◽  
Fracture Network ◽  
Hydraulic Fracture Network ◽  
Shale Reservoirs

Fuel Flexible Biomass Reburn Technology

2009 ◽  
Author(s):  
Guang Xu ◽  
Wei Zhou ◽  
Larry Swanson
Keyword(s):  
Particle Size ◽  
Bituminous Coal ◽  
Nox Reduction ◽  
Unburned Carbon ◽  
Gas Temperature ◽  
Mean Particle Size ◽  
High Volatility ◽  
Order Of Magnitude ◽  
Char Reactivity ◽  
Computational Fluid Dynamics Cfd

Biomass reburn is a low NOx alternative to cofiring that effectively uses the high volatility and high char reactivity of biomass for NOx reduction. In this paper, computational fluid dynamics (CFD) and thermal modeling, and a NOx prediction model were used to evaluate the impacts of sawdust/coal reburn on the performance of a 250 MW opposed-fired boiler burning bituminous coal as the primary fuel. The results showed that the reburn system maintained overall boiler performance with a 50 – 70 °F reduction in the furnace exit gas temperature. Predicted losses in thermal efficiency were caused by the lower biomass fuel heating value (similar to biomass cofiring) and increase in unburned carbon. The higher unburned carbon emissions were attributed to an order of magnitude larger biomass mean particle size relative to bituminous coal. Thus, LOI emissions can be improved significantly by reducing the biomass mean particle size. The NOx predictions showed that for reburn rates above about 19%, adding dry sawdust biomass to a coal reburn system can improve NOx reduction; i.e., using pure dry sawdust as reburn fuel at 30% of the total heat input can lead to NOx levels about 30% less than those for pure coal reburn under for similar firing conditions.

scholarly journals Study of GLR and Inlet Velocity on Hydrocyclone for Fracturing Flow-Back Fluids

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Bing Liu ◽  
Huajian Wang ◽  
Luncao Li ◽  
Zhenjiang Zhao ◽  
Liping Xu ◽  
...  
Keyword(s):  
Particle Size ◽  
Separation Efficiency ◽  
Tangential Velocity ◽  
Reynolds Stress Model ◽  
Optimum Range ◽  
Inlet Velocity ◽  
Split Ratio ◽  
Vortex Finder ◽  
Computational Fluid Dynamics Cfd ◽  
Solid Liquid

In this work, based on the Reynolds stress model (RSM) of the computational fluid dynamics (CFD) software Fluent and experimental method, the velocity field, pressure characteristics, split ratio, and separation efficiency of the hydrocyclone are analyzed under different gas-liquid ratios (GLRs). For the inlet velocity, the lower limit is ascertained by the flow field stability, the upper limit is largely determined by the energy consumption, and the optimum range is 4 m/s to 10 m/s. Within the optimum range, the peak value of tangential velocity increases while the GLR increases, whereas the pressure and pressure drop decrease. With the increase in the GLR, the axial velocity decreases, and the locus of zero vertical velocity shifts inward. The increase in the GLR causes more gas to collect at the vortex finder, which hinders the discharge of the solid-liquid mixture from the overflow, and the larger the GLR, the faster the decrease in the split ratio. The separation efficiency of particles with a particle size of 15 μm is increased by 6.75%, and the separation efficiency of particles with a particle size of 30 μm is increased by 0.57%. Meanwhile, the separation efficiency is increased by 2.43%, and the cut size d50 is reduced as the GLR increases.

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