Distribution of solid particles in a mixed vessel

1990 ◽  
Vol 55 (9) ◽  
pp. 2169-2181 ◽  
Author(s):  
Petr Bílek ◽  
František Rieger
Keyword(s):  
Solid Phase ◽  
Solid Particles ◽  
Concentration Measurement ◽  
Concentration Profiles ◽  
Conductivity Method ◽  
Phase Concentration ◽  
Solid Phase Concentration ◽  
Vessel Bottom ◽  
Vessel Axis

The aim of our research was to study the axial, radial and tangential solid phase concentration profiles in a mixed vessel. The conductivity method was used for the concentration measurement. We accomplished the measurement in eleven points in five heights above the vessel bottom. The points were situated on three vertical planes passing through the vessel axis and on five values of radii. It was determined by means of statistic test of variance if it was possible to measure the concentration only in one point in each distance from the vessel bottom and neglect the radial and tangential concentration differences.

Doping and Alloying of Hydrogenated Amorphous Germanium Films Prepared by DC-Magnetron Sputtering

1993 ◽  
Vol 297 ◽  
Author(s):  
T. DrÜsedau ◽  
A. Annen ◽  
B. SchrÖder
Keyword(s):  
Solid Phase ◽  
Dark Conductivity ◽  
Concentration Addition ◽  
Phase Concentration ◽  
N Doping ◽  
Solid Phase Concentration ◽  
Donor States ◽  
B Doping ◽  
Si Content ◽  
High Level

In this paper we present a detailed study of doping and alloying effects in a-Ge:H due to the incorporation of phosphorus, nitrogen, oxygen, boron, carbon and silicon. The film characterization was performed by means of quantitative analysis , optical absorption in the band and subband range and conductivity measurements. N and O were found to form donor states resulting in an increase of the dark conductivity up to five orders of magnitude. The maximum value of 0.3 (Ωcm)-1 has been obtained by N-doping of about 1 at% solid phase concentration, which exceeds the effect of P doping. B doping causes a decrease of the dark conductivity to a minimum of 10-6 (Ωcm)-1 at 150 ppm solid phase concentration. Addition of Si and C up to concentrations of about 5 at % does not influence the subgap absorption, where best values of E0<50 meV and α(0.6 eV)<10 cm-1 were obtained for the Urbach energy and midgap absorption, respectively. A Si content of 1 at % decreases the dark conductivity, whereas the normalized photoconductivity remains at a high level of ŋμτ=10-5 cm2V-1.

Wash-out of solid phase from the mechanically stirred charge

1980 ◽  
Vol 45 (8) ◽  
pp. 2152-2163 ◽  
Author(s):  
Václav Machoň ◽  
Vladimír Kudrna ◽  
Vlasta Hudcová
Keyword(s):  
Time Dependence ◽  
Fresh Water ◽  
Theoretical Approach ◽  
Solid Phase ◽  
Material Balance ◽  
Sufficient Accuracy ◽  
Experimental Measurements ◽  
Simple Material ◽  
Phase Concentration ◽  
Solid Phase Concentration

Experimental measurements were performed of the time dependence of solid phase concentration in suspension at the outlet from the apparatus with the mechanically stirred charge. Suspension was being withdrawn continuously with fresh water supplied into the charge. Validity of the theoretical approach proposed earlier has been verified by the performed experiments. It has been demonstrated that the studied effect can be under certain conditions described with sufficient accuracy by a simple material balance of the solid phase in the system.

scholarly journals Effect of a Symmetric Contraction on the Concentration Profiles of a Particle-Laden Slurry

2011 ◽  
Author(s):  
A. Deshpande ◽  
K. Ramisetty ◽  
F. W. Chambers ◽  
M. E. McNally ◽  
R. M. Hoffman
Keyword(s):  
Single Phase ◽  
Solid Phase ◽  
Fluid Dynamic ◽  
Density Ratio ◽  
Primary Phase ◽  
Solid Particles ◽  
Concentration Profiles ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Slurry Concentration

In-line measurements and sample stream withdrawals for on-line and/or at-line measurements of slurries flowing in horizontal pipes can be complicated by nonuniform slurry profiles. More uniform profiles would improve measurements. Area contractions are a common means used to produce more uniform velocity fields for single phase flows. For example, contractions are used to condition the flow entering wind tunnel test sections and make velocity profiles more uniform at venturi throats. It was desired to determine whether area contractions could be used to make slurry concentration profiles more uniform in horizontal pipe flows. An ASME flow nozzle with a contraction diameter ratio of 0.5 was chosen as a well defined geometry to consider in a Computational Fluid Dynamic (CFD) study of the effects of a contraction on slurry concentration profiles. The pipe was 2.8 m long with a 50.8 mm diameter. The entrance of the contraction was placed at 35 pipe diameters from the inlet in fully developed flow. A length of 20 diameters followed the contraction. The slurry had a xylene liquid phase and an ADP solid phase with a density ratio of 1.7. The simulations were performed at primary phase velocities of 2 m/s and 4 m/s, corresponding to Reynolds numbers of 1.4E05 and 2.8E05. Spherical particle diameters of 38, 75, and 150 μm were used at concentrations of 0.05, 0.2, and 0.3. ANSYS FLUENT 12 software was used with the standard k-ε turbulence model and standard wall function. The mixture multi-phase model was used for the two-phase flow. An unstructured tetrahedral meshing scheme was used with 1.4 million elements. The grid was adjusted until the condition 30 < y+ <60 for the mesh point nearest the wall was satisfied. A grid refinement study was performed to insure grid independence. The computational scheme first was validated by comparing pipe flow velocity and concentration profiles to results in the literature. The computations performed with the contraction showed that in all cases the concentration profiles of the solid particles displayed greater uniformity than the profiles in the pipe upstream of the contraction. The effect of the contraction was more pronounced for the larger particles. As in the case of single phase flows, the contraction caused the axial turbulence intensity to decrease. The greater uniformity of the concentration profiles at the exit plane of the nozzle, suggest that the contraction can provide better conditions for performing measurements of a particle-laden slurry.

Application of solid-phase concentration-dependent HSDM to the acid dye adsorption system

AIChE Journal ◽  
2004 ◽  
Vol 51 (1) ◽  
pp. 323-332 ◽  
Author(s):  
Vinci K. C. Lee ◽  
John F. Porter ◽  
Gordon McKay ◽  
Alexander P. Mathews
Keyword(s):  
Solid Phase ◽  
Dye Adsorption ◽  
Adsorption System ◽  
Acid Dye ◽  
Phase Concentration ◽  
Solid Phase Concentration
Sign in / Sign up

Export Citation Format

Share Document