Radial pressure profiles in a cold‐flow gas‐solid vortex reactor

A unique normalized radial pressure profile characterizes the bed of a gas‐solid vortex reactor over a range of particle densities and sizes, solid capacities, and gas flow rates: 950–1240 kg/m³, 1–2 mm, 2 kg to maximum solids capacity, and 0.4–0.8 Nm³/s (corresponding to gas injection velocities of 55–110 m/s), respectively. The combined momentum conservation equations of both gas and solid phases predict this pressure profile when accounting for the corresponding measured particle velocities. The pressure profiles for a given type of particles and a given solids loading but for different gas injection velocities merge into a single curve when normalizing the pressures with the pressure value downstream of the bed. The normalized—with respect to the overall pressure drop—pressure profiles for different gas injection velocities in particle‐free flow merge in a unique profile. © 2015 The Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 61: 4114–4125, 2015     

Calculation of the Critical Radius of an Inclusion for Fracture from a Porous Matrix under the Conditions of Plastic Deformation

This work is concerned with the theoretical determination of the critical radius of a rigid inclusion at the moment of its decohesion from the material of a porous matrix. The criterion of V. V. Skorokhod served as the basis for analysis of the limiting state. Change of the porosity and accumulated strain of the solid phase in the process of plastic deformation were taken into account in the calculations. It is shown that the values of investigated properties depend on the concentration of inclusions and the porosity of the ductile layer. The dependence of accumulated strain in the solid phase on porosity was obtained.     

Numerical Modelling of the Compaction of Powder Articles of Complex Shape in Rigid Dies: Effect of Compaction Scheme on Density Distribution. Part 2. Modelling Procedure and Analysis of Forming Schemes

A modified finite element method is proposed using a previously formulated version of porous body plasticity theory, which is intended for modelling compaction of powder materials. A number of compaction schemes are considered for articles with changes with respect to height. The effect of external friction and compaction scheme on the occurrence of compaction is analyzed. A compaction scheme whose use provides preparation of powder articles with uniform density distribution is studied separately. Theoretical results obtained are quite close to experimental data.     

Mechanics of Sintering Materials with Bimodal Pore Distribution. I. Effective Characteristics of Biporous Materials and Equations for the Evolution of Pores of Different Radii

A model of sintering for materials with bimodal pore distribution is formulated as a generalization of the continuum isotropic theory of sintering. In contrast to known models that only contain one behavioral parameter, i.e. porosity, the model suggested is described by two parameters for each type of pore. The evolution equations for each type of pore as well as the effective viscosity coefficients and Laplace pressure (sintering potential) are determined by unit cell analysis.