The Behavior of Cement-Bonded Particleboard with Modified Composition under Static Load Stress

This article presents research on the behavior of cement-bonded particleboards under mechanical stress caused by the static load. The composition of the boards was modified using alternative raw materials–dust (DU) forming during the processing of cement-fibre boards and particle mixture (PM) generated in the production of cement-bonded particleboards. The particleboards (1-year-old) were subjected to an adverse environment (100 to 250 frost cycles). Mechanical parameters were tested, and the development of defects during static load of the boards by bending was analyzed using acoustic emission. Particleboards with modified compositions are slightly more resistant to adverse environments. The results of the acoustic emission showed the different types of defects occurring under stress by bending. Standard-composition particleboards showed defects located mainly under the cylindrical stress-test head. The modified boards showed larger location distribution of the occurring defects that were also concentrated further away from the cylindrical stress head. The energy during the occurrence of defects was higher in the modified boards in the location of weight application than in the reference boards.

Two-Pressure Model of Particle-Fluid Mixture Flow with Pressure-Dependent Viscosity in a Porous Medium

Equations governing the flow of a fluid-particle mixture with variable viscosity through a porous structure are developed. Method of intrinsic volume averaging is used to average Saffman’s dusty gas equations. A modelling flexibility is offered in this work by introducing a dust-phase partial pressure in the governing equations, interpreted as the pressure necessary to maintain a uniform particle distribution in the flow field. Viscosity of the fluid-particle mixture is assumed to be variable, with variations in viscosity being due to fluid pressure. Particles are assumed spherical and Stokes’ coefficient of resistance is expressed in terms of the pressure-dependent fluid viscosity. Both Darcy resistance and the Forchheimer micro-inertial effects are accounted for in the developed model

Numerical Simulation of a Rectangular Clarifier Using Drift-Flux Model in OpenFOAM

A computation fluid dynamic (CFD) simulation of a rectangular clarifier is performed in this study using a drift-flux model in OpenFOAM CFD code. Using this model with turbulence model, the key characteristics (re-circulation and sedimentation) of water-particle mixture flow in a rectangular clarifier are reasonably reproduced. A fairly good agreement is obtained between the simulation results and experimental data of the velocity profiles. Thus, with the demonstrated capability of this CFD model for the prediction of hydrodynamic and sedimentation behavior of water-particle mixture flow, several design issues such as the determination of the best location of baffle in a clarifier can be investigated and addressed. This method can not only provide general conceptual information at the initial design stage but can also be used to perform analysis of different configurations and the effect of changes in operational parameters.