The role of residual char on ash flow behavior, Part 3: Effect of Fe2O3 content on ash fusibility and carbothermal reaction

Phosphate ore slurry is a suspension of insoluble particles of phosphate rock, the primary raw material for fertilizer and phosphoric acid, in a continuous phase of water. This suspension has a non-Newtonian flow behavior and exhibits yield stress as the shear rate tends toward zero. The suspended particles in the present study were assumed to be noncolloidal. Various grades and phosphate ore concentrations were chosen for this rheological investigation. We created some experimental protocols to determine the main characteristics of these complex fluids and established relevant rheological models with a view to simulate the numerical flow in a cylindrical pipeline. Rheograms of these slurries were obtained using a rotational rheometer and were accurately modeled with commonly used yield-pseudoplastic models. The results show that the concentration of solids in a solid–liquid mixture could be increased while maintaining a desired apparent viscosity. Finally, the design equations for the laminar pipe flow of yield pseudoplastics were investigated to highlight the role of rheological studies in this context.

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Experimental and Numerical Investigations of a Turbulent Flow Behavior in Isolated and Nonisolated Conical Diffusers

Journal of Fluids Engineering ◽

10.1115/1.4003236 ◽

2011 ◽

Vol 133 (1) ◽

Cited By ~ 5

Author(s):

F. Aloui ◽

E. Berrich ◽

D. Pierrat

Keyword(s):

Turbulent Flow ◽

Flow Behavior ◽

Piv Measurements ◽

Numerical Investigations ◽

Image Velocimetry ◽

Sst Model ◽

Proper Orthogonal ◽

Hydraulic Circuits

In some industrial processes, and especially in agrofood industries, the cleaning in place mechanism used for hydraulic circuits plays an important role. This process needs a good knowledge of the hydrodynamic flows to determinate the appropriate parameters that assure a good cleaning of these circuits without disassembling them. Generally, different arrangements are present in these hydraulic circuits, such as expansions, diffusers, and elbows. The flow crossing these singularities strongly affects the process of cleaning in place. This work is then a contribution to complete recent studies of “aliments quality security” project to ameliorate the quality of the cleaning in place. It presents experimental and numerical investigations of a confined turbulent flow behavior across a conical diffuser (2α=16 deg). The role of a perturbation caused by the presence of an elbow in the test section, upstream of the progressive enlargement, was studied. The main measurements were the static pressure and the instantaneous velocity fields using the particle image velocimetry (PIV). Post-processing of these PIV measurements were adopted using the Γ2 criterion for the vortices detection and the proper orthogonal decomposition (POD) technique to extract the most energetic modes contained in the turbulent flow and to the turbulent flow filtering. A database has been also constituted and was used to test the validity of the most models of turbulence, and in particular, a variant of the shear stress transport (SST) model.

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Deformation Mechanisms and Solid-Solution Strengthening in Ordered Alloys

MRS Proceedings ◽

10.1557/proc-213-499 ◽

1990 ◽

Vol 213 ◽

Cited By ~ 3

Author(s):

Dennis M. Dimiduk ◽

Satish Rao

Keyword(s):

Solid Solution ◽

Flow Behavior ◽

Stoichiometric Composition ◽

Dislocation Core ◽

Deformation Mechanisms ◽

Solid Solution Hardening ◽

Solid Solution Strengthening ◽

Ordered Alloys ◽

Solute Hardening

ABSTRACTFundamental to understanding the results of alloy design studies, is the need for understanding the intrinsic role of solutes in a particular compound. For many compounds such an understanding must be built from a systematic exploration of the role of deviations from the stoichiometric composition as well as the role of ternary solute additions on the variation of flow behavior. Within most intermetallic systems the problem is complicated since the fundamental mechanisms of flow are not well established and, in those systems where these mechanisms are known, thermal activation can lead to dislocation-core transformations and changes in the operative slip systems with temperature. In general, flow may be governed by more than one dislocation process at a given temperature and deformation twinning may be a major contributing deformation mechanism. The problem of isolating the mechanisms of solid-solution hardening may, therefore, require treatment as a problem of combined strengthening mechanisms operating in parallel. This paper reviews the key aspects of deformation mechanisms and solute strengthening in intermetallic alloys. Classical elastic theories of solute hardening serve as an origin, from which, the progress made to date in isolating the mechanisms of solute hardening in ordered alloys is discussed.

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CFD Comparison of Steady and Unsteady Flow Through a Human Nasal Passage

ASME 2009 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2009-206673 ◽

2009 ◽

Author(s):

Brian Savilonis ◽

Kalen Smith

Keyword(s):

Unsteady Flow ◽

Steady Flow ◽

Flow Behavior ◽

Flow Dynamics ◽

Nasal Passage ◽

Normal Breathing ◽

Flow Through ◽

Nasal Flow

Understanding of the transnasal pressure and flow behavior during normal breathing conditions has been a subject of much discussion and research. In particular we are interested in testing the hypothesis of quasi-steady flow as well as the role of turbulence on nasal flow dynamics.

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Liquid Sheet Breakup in Gas-Centered Swirl Coaxial Atomizers

Journal of Fluids Engineering ◽

10.1115/1.4000737 ◽

2010 ◽

Vol 132 (1) ◽

Cited By ~ 27

Author(s):

V. Kulkarni ◽

D. Sivakumar ◽

C. Oommen ◽

T. J. Tharakan

Keyword(s):

Flow Behavior ◽

Liquid Sheet ◽

Liquid Sheets ◽

Sheet Surface ◽

Air Jet ◽

Entrainment Process ◽

Sheet Breakup ◽

Experimental Fluids ◽

Flow Experiments

The study deals with the breakup behavior of swirling liquid sheets discharging from gas-centered swirl coaxial atomizers with attention focused toward the understanding of the role of central gas jet on the liquid sheet breakup. Cold flow experiments on the liquid sheet breakup were carried out by employing custom fabricated gas-centered swirl coaxial atomizers using water and air as experimental fluids. Photographic techniques were employed to capture the flow behavior of liquid sheets at different flow conditions. Quantitative variation on the breakup length of the liquid sheet and spray width were obtained from the measurements deduced from the images of liquid sheets. The sheet breakup process is significantly influenced by the central air jet. It is observed that low inertia liquid sheets are more vulnerable to the presence of the central air jet and develop shorter breakup lengths at smaller values of the air jet Reynolds number Reg. High inertia liquid sheets ignore the presence of the central air jet at smaller values of Reg and eventually develop shorter breakup lengths at higher values of Reg. The experimental evidences suggest that the central air jet causes corrugations on the liquid sheet surface, which may be promoting the production of thick liquid ligaments from the sheet surface. The level of surface corrugations on the liquid sheet increases with increasing Reg. Qualitative analysis of experimental observations reveals that the entrainment process of air established between the inner surface of the liquid sheet and the central air jet is the primary trigger for the sheet breakup.

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Role of Deformable Fine Spinel Particles in High-Strain-Rate Superplastic Flow of Tetragonal ZrO2

MRS Proceedings ◽

10.1557/proc-821-p8.28 ◽

2004 ◽

Vol 821 ◽

Author(s):

Koji Morita ◽

Keijiro Hiraga ◽

Byung-Nam Kim ◽

Yoshio Sakka

Keyword(s):

High Strain Rate ◽

Strain Rate ◽

High Strain ◽

Flow Behavior ◽

Grain Boundary Sliding ◽

Dislocation Motion ◽

Particle Dispersion ◽

Stress Concentrations ◽

Tensile Direction

AbstractThe role of MgAl2O4 spinel particle dispersion in high-strain-rate superplasticity (HSRS) of tetragonal ZrO2 was examined by characterizing microstructural changes during deformation. The dispersed spinel particles elongate with strain along tensile direction and the elongation tends to be pronounced with increasing strain rate. In the elongated spinel particles, intragranular dislocations lying along the elongated direction were observed, suggesting that the elongation relates to the dislocation motion. The flow behavior characterized by a stress exponent of ≈ 2.0 suggests that grain boundary sliding (GBS) is the predominant flow mechanism. The dislocation-induced plasticity in the spinel particles may assist the relaxation of stress concentrations exerted by GBS, leading to HSRS in tetragonal ZrO2.

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