Simulation of In-Flight Reduction of the Fine Iron Ore Concentrate by Hydrogen

Abstract A mathematical model has been proposed to simulate a novel method for direct reduction of iron concentrate by hydrogen. Flight of fine particles in a vertical reactor containing a gaseous mixture of H2-N2-H2O has been studied. Effect of generating gaseous jet on the residence time of the particles has been also investigated. Coupled turbulent Navier-Stokes equations with eddy kinetic energy equation have been solved using a developed homemade code. Kinetics of this reaction has been studied using the unreacted core model. Accuracy of the model predictions has been approved by the experimental data. Finally, effects of vital variables (i. e. temperature, particle size, hydrogen concentration and particle feed rate) on the particle residence time and also fractional conversion have been studied.

Download Full-text

On the Accelerated Settling of Fine Particles in a Bidisperse Slurry

Mathematical Problems in Engineering ◽

10.1155/2015/169125 ◽

2015 ◽

Vol 2015 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Leonid L. Minkov ◽

Yuliya O. Stepanova ◽

Johann Dueck ◽

Elizaveta V. Pikushchak

Keyword(s):

Fine Particles ◽

Stokes Equations ◽

Fine Fraction ◽

Particle Diameter ◽

Sedimentation Velocity ◽

Navier Stokes ◽

Circulation Zone ◽

Navier Stokes Equations ◽

Volume Average ◽

Bidisperse Suspension

An estimation of increasing the volume average sedimentation velocity of fine particles in bidisperse suspension due to their capturing in the circulation zone formed in the laminar flow of incompressible viscous fluid around the spherical coarse particle is proposed. The estimation is important for an explanation of the nonmonotonic shape of the separation curve observed for hydrocyclones. The volume average sedimentation velocity is evaluated on the basis of a cellular model. The characteristic dimensions of the circulation zone are obtained on the basis of a numerical solution of Navier-Stokes equations. Furthermore, these calculations are used for modelling the fast sedimentation of fine particles during their cosedimentation in bidisperse suspension. It was found that the acceleration of sedimentation of fine particles is determined by the concentration of coarse particles in bidisperse suspension, and the sedimentation velocity of fine fraction is proportional to the square of the coarse and fine particle diameter ratio. The limitations of the proposed model are ascertained.

Download Full-text

Mathematical Modelling of Thermo-Hydro-Mechanical Behaviour for Concrete under Elevated Temperature

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.670-671.355 ◽

2014 ◽

Vol 670-671 ◽

pp. 355-364

Author(s):

Shao Bo Zhang ◽

Xiao Chun Wang ◽

Xin Pu Shen

Keyword(s):

Elevated Temperature ◽

Stokes Equations ◽

Constitutive Relations ◽

Gaseous Mixture ◽

Mass Conservation ◽

Momentum Conservation ◽

Conservation Equation ◽

Navier Stokes ◽

Navier Stokes Equations ◽

Energy Conservation Equation

A hydro-thermo-mechanical model was presented for concrete at elevated temperature. Three phases of continuum were adopted in this model: gaseous mixture of water vapor and dry air, liquid water, and solid skeleton of concrete. Mass conservation equations, linear momentum conservation equation, and energy conservation equation were derived on the basis of the macroscopic Navier-Stokes equations for a general continuum, along with assumptions made for the purpose of simplification. Mathematical relationships between selected primary variables and secondary variables were given with existing data from references. Specifications of the constitutive relations were made for the kinetic variables and their conjugate forces.

Download Full-text

Numerical Analysis of Solitary Wave Influence on the Filmwise Condensation in Presence of Non-Condensable Gases

Volume 4: Computational Fluid Dynamics, Neutronics Methods and Coupled Codes; Student Paper Competition ◽

10.1115/icone14-89677 ◽

2006 ◽

Author(s):

Krzysztof Karkoszka ◽

Henryk Anglart

Keyword(s):

Heat Transfer ◽

Boundary Conditions ◽

Stokes Equations ◽

Numerical Models ◽

Gaseous Mixture ◽

Heat Transfer Process ◽

Navier Stokes ◽

Condensation Process ◽

Navier Stokes Equations ◽

Process Solutions

This paper is dealing with the analysis of condensation in presence of non-condensable gas on a laminar liquid film falling down on a vertical smooth surface. Particular interest is focused on the influence of solitary waves on the condensation process. Solutions to the pressure, velocity, temperature and additional scalar variable fields are obtained numerically by solving two-dimensional Navier–Stokes equations formulated in a general coordinate system and applying the artificial compressibility method. The whole system of equations together with adequate boundary conditions is implemented using the finite difference method and solved in the Matlab® code. Both implicit Crank–Nicolson and Euler schemes for the time derivatives are initially used and the latter one is chosen as a more stable. All computations are carried out with prescribed geometry for a film and gas domains and a special attention is focused mainly on the modelling of the influence of the interfacial boundary conditions on the heat transfer process between gaseous mixture and liquid phases. Description of the physical, mathematical and numerical models and several examples of the solutions are presented. Conclusions on the wave hydrodynamics influence on the heat transfer during phase change process are drawn.

Download Full-text

Hydrodynamic limit for the Vlasov-Navier-Stokes equations. Part II: Fine particles regime.

Indiana University Mathematics Journal ◽

10.1512/iumj.2004.53.2509 ◽

2004 ◽

Vol 53 (6) ◽

pp. 1517-1536 ◽

Cited By ~ 67

Author(s):

Thierry Goudon ◽

Pierre-Emmanue Jabin ◽

Alexis Vasseur

Keyword(s):

Hydrodynamic Limit ◽

Fine Particles ◽

Stokes Equations ◽

Navier Stokes ◽

Navier Stokes Equations

Download Full-text

Remarks on the asymptotic behaviour of solutions to the compressible Navier–Stokes equations in the half-line

Proceedings of the Royal Society of Edinburgh Section A Mathematics ◽

10.1017/s030821050200032x ◽

2002 ◽

Vol 132 (03) ◽

pp. 627

Keyword(s):

Asymptotic Behaviour ◽

Stokes Equations ◽

Half Line ◽

Navier Stokes ◽

Navier Stokes Equations ◽

Asymptotic Behaviour Of Solutions

Download Full-text

Effects of stator splitter blades on aerodynamic performance of a single-stage transonic axial compressor

JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES ◽

10.15282/jmes.14.4.2020.05.0579 ◽

2020 ◽

Vol 14 (4) ◽

pp. 7369-7378

Author(s):

Ky-Quang Pham ◽

Xuan-Truong Le ◽

Cong-Truong Dinh

Keyword(s):

Stokes Equations ◽

Three Dimensional ◽

Axial Compressor ◽

Aerodynamic Performance ◽

Numerical Results ◽

Single Stage ◽

Navier Stokes ◽

Navier Stokes Equations ◽

Operating Stability ◽

Length Coverage

Splitter blades located between stator blades in a single-stage axial compressor were proposed and investigated in this work to find their effects on aerodynamic performance and operating stability. Aerodynamic performance of the compressor was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations using the k-e turbulence model with a scalable wall function. The numerical results for the typical performance parameters without stator splitter blades were validated in comparison with experimental data. The numerical results of a parametric study using four geometric parameters (chord length, coverage angle, height and position) of the stator splitter blades showed that the operational stability of the single-stage axial compressor enhances remarkably using the stator splitter blades. The splitters were effective in suppressing flow separation in the stator domain of the compressor at near-stall condition which affects considerably the aerodynamic performance of the compressor.

Download Full-text