Evolution of a spherical inhomogeneity in a bidisperse fluidized layer

Development of a mathematical model and calculated analytical dependencies for determining the trajectories and parameters of grain movement in a vibro-fluidized layer of grain material components under the action of a pulsating air flow. They are based on the methods of deterministic mathematical modeling and theoretical mechanics based on the equations of motion of a material point at a variable air flow speed and the action of a pulsating air flow. Theoretical studies were carried out using the methods of mathematical analysis and modeling. The research results were processed using elements of the theory of probability and mathematical statistics using software packages; to determine the rational parameters of the process, the method of statistical experiment planning was used. A mathematical description of the motion of the grain material particles in a combined vibration-air separator under the action of a pulsating air flow of variable speed is given. The trajectories of motion of particles with different sizes are obtained. The obtained equation of motion of a particle under the influence of a pulsating air flow makes it possible to determine the dependence of the speed of movement of the material in a vibro-fluidized layer of grain material on a number of factors: the geometric parameters of the sieve-free sieve, the feed angle of the material, the initial kinematic mode of the material, the index of the kinematic mode of the sieve-free sieve, as well as the coefficient of windage of the grain. On the basis of theoretical studies, the possibility of separating particles of grain material into fractions according to aerodynamic properties with vibropneumatic loading of grain into the channel has been determined. The use of a pulsating air flow as a separating carrier, and taking into account the deflecting forces, made it possible to significantly increase the splitting of the trajectories and the criterion for dividing the grain into fractions.

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Current Control of Product Granulometric Composition in Apparatus with Fluidized Layer

Journal of Automation and Information Sciences ◽

10.1615/jautomatinfscien.v31.i12.130 ◽

1999 ◽

Vol 31 (12) ◽

pp. 97-106

Author(s):

Yaroslav N. Kornienko ◽

Nikolay V. Podmogilnyi ◽

Anton N. Silvestrov ◽

Roman F. Khotyachuk

Keyword(s):

Granulometric Composition ◽

Current Control ◽

Fluidized Layer

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Unsteady mass exchange between a bubble and medium in a reactor with fluidized layer

Journal of Applied Mathematics and Mechanics ◽

10.1016/0021-8928(75)90042-8 ◽

1975 ◽

Vol 39 (1) ◽

pp. 107-118

Author(s):

Iu.P. Gupalo ◽

Iu.S. Riazantsev ◽

Iu.A. Sergeev

Keyword(s):

Mass Exchange ◽

Fluidized Layer

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Mathematical Modeling and Optimization of Fluidized Layer Carbonitriding Process for 1C 25 Steel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1143.180 ◽

2017 ◽

Vol 1143 ◽

pp. 180-187

Author(s):

Marian Iulian Neacsu ◽

Sorin Dobrovici

Keyword(s):

Mathematical Modeling ◽

Mathematical Model ◽

Software Package ◽

Order Equation ◽

Graphical Interface ◽

Technological Parameters ◽

Fluidized Layer ◽

The Mathematical Model ◽

Hardness Values ◽

Temperature Depth

This paper presents the experiment-based mathematical modelling of fluidized bed carbonitriding process for 1C 25 steel meant to optimize this type of thermochemical processing.Based on experimental results, the mathematical model was developed, which is a second order equation with three unknown terms (parameters): temperature, depth of carbonitrided layer, the percentage of ammonia.The mathematical model allowed the simulation of the fluidized layer carbonitriding process according to its parameters and the thermal energy optimization for obtaining HV hardness values in the range 300-400 MPa.Using the software package Matlab a graphical interface was done, through which all the combinations of technological parameters of the carbonitriding process are determined, leading to obtaining values of microhardness between 300 and 400 MPa, as well as the amount of energy consumed for each variant. The variant consuming the lowest energy is considered optimal.

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Inferences on Mixed Snow Avalanches from Field Observations

Geosciences ◽

10.3390/geosciences10010002 ◽

2019 ◽

Vol 10 (1) ◽

pp. 2 ◽

Cited By ~ 5

Author(s):

Dieter Issler ◽

Peter Gauer ◽

Mark Schaer ◽

Stefan Keller

Keyword(s):

Snow Cover ◽

Flow Regimes ◽

Height Velocity ◽

Momentum Balance ◽

Dense Layer ◽

Snow Avalanches ◽

Valley Bottom ◽

Fluidized Layer ◽

Suspension Layer ◽

Run Up

Observations of the deposits, flow marks, and damages of three mixed-snow avalanches of widely different size were analyzed with regard to flow regimes, velocities, pressures, densities, flow depths, erosion modes, and mass balance. Three deposit types of different density and granulometry could be clearly discerned in these avalanches. They are attributed to dense, fluidized, and suspension flow regimes, respectively. Combining observations, we estimated the density in the fluidized layer as 35–100 kg m − 3 , in good agreement with inferences from pressure measurements. Upper bounds for the suspension layer density, arising from the run-up height, velocity, and damage pattern, are about 5 kg m − 3 at the valley bottom. An approximate momentum balance of the dense layer suggests that the snow cover was eroded to considerable depth, but only partly entrained into the flow proper. The suspension layer had largely lost its erosive power at the point where it separated from the denser parts of the avalanche. Our estimates shed doubt on collisions between snow particles and aerodynamic forces at the head of the avalanche as sole mechanisms for creating and upholding the fluidized layer. We conjecture that the drag from air escaping from the snow cover as it is being compressed by the overriding avalanche could supply the missing lift force.

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