Papers by Keyword: Particle

Abstract: In silicon steels, interaction of grain boundaries with particles occurs in a selective way. Currently, it is very difficult to include this preferential interaction directly in the classical simulation models. A new approach of grain growth simulation based on the concept of curvature-driven migration of the grain boundaries in the presence of particles has been used to study the abnormal grain growth (AGG) in Fe-3%Si alloy.

Abstract: A huge number of different process types are in use to produce magnesium-based composites. Depending on the reinforcement type, all the processes can be subdivided into solid state or powder metallurgical (PM) and liquid phase or ingot metallurgical (IM) processes. In this paper we will focus on ingot metallurgy processes. These liquid state processes result quite often in a very good interface of reinforcement with the magnesium matrix. The liquid processes can be further subdivided into infiltration techniques, casting processes and spray deposition. Those are the most inexpensive processing technologies for discontinuous, reinforced magnesium-based composites. When produced using melting processes, nanoparticle-reinforced magnesium composites are expected to improve in strength, due to the grain refinement described in the Hall-Petch relation. When an isotropic distribution of nanoparticles is achieved, the composites are additionally expected to be Orowan-strengthened. That is why nanosized reinforcements are expected to represent the future for improving the properties of magnesium-based metal matrix composites.

Abstract: The micro/nano particles of silicone rubber were prepared with α, ω-dihydroxy polyorganosiloxane, as basic polymer and crosslinking agent via emulsion polymerization method at room temperature. The structure and performance of the particles were characterized by transmission electron microscopy (TEM), FT-IR, thermogravimetric analysis (TGA) and X-ray diffraction (XRD). The results indicated that the particles had certain ordered structure and thermal stability.

Abstract: Acoustic radiation forces can be used to collect particles within microfluidic systems. The standard way of doing this is to excite a one-dimensional standing wave between a pair of solid walls; the particles will then typically collect at the pressure nodes. Higher degrees of positioning control can be achieved by excitation of additional orthogonal one-dimensional standing waves; this usually requires further walled constraints (two-dimensional collection for example requiring a chamber rather than a channel). In this work we examine methods of exciting two-dimensional fields in a channel using a single transducer as well as the use of pressure fields which are not one-dimensional in nature and the advantages they can offer.

Abstract: A numerical simulation procedure for studying deposition of aerosol particles in a laminar convection flow of radiating gas over a backward-facing step including the effect of thermal force is developed. In the gas flow, all of the heat transfer mechanisms consisting of conduction, convection and radiation take place simultaneously. Behavior of solid particles is studied numerically based on an Eulerian–Lagrangian method. Two dimensional Navier-Stokes and energy equations are solved using CFD techniques, while the radiating transfer equation (RTE) is solved by discrete ordinate method (DOM) for calculating radiative heat flux distribution. The objective of this research is to study the effect of Reynolds number variation and also radiation on thermophoretic deposition of particles. Numerical results show a decrease in deposition percent by increasing in Reynolds number and the radiation effect is negligible. The results are compared with the existing experimental and numerical data and good agreement is found.

Abstract: Flue gas emissions and particle size distribution were investigated during combustion experiments of wood, forest residue and mixtures of these two. The combustion experiments were carried out in a grate fired multi-fuel reactor with and without air staging at stable operation conditions and constant temperature of 850 °C. The overall excess air ratio was held at 1.6, and the primary excess air ratio was 0.8 during air staged experiments. NOx emissions are reduced by air staging. Fly ash particle concentration of forest residues in the flue gas is lower than wood. Aerosols number increased in the staged experiments for fuel blends.

Abstract: This study proposed a new type of hydrocyclone. A rotating ring containing one pair of symmetric blades was attached to the overflow pipe. The momentum of the inlet fluid drove the ring/blades to rotate, and the rotating blades swept small-sized particles to the hydrocyclone wall to be discharged from underflow. This design can destroy circulation flow on hydrocyclone roof and make small-sized particles to be separated.

Abstract: The principle of biomass briquetting, the advantages and disadvantages of biomass briquette machine and the current research status were introduced in this paper. The influence of the four factors biomass particle size, moisture, pressure and compression speed to formation density and compressive strength was summarized, by orthogonal test method. The results show that, the influence of biomass size to the formation density is largest and to the compressive strength is least. The biomass size in the range of<40 mesh is best. The influence of compressing speed to compressive strength is largest and to formation density is least. The speed about 60mm/min is best. The influence of biomass moisture content and pressure cannot be neglected, 15% and 10MPa are best in this paper.

Abstract: This paper discusses particle deposition in rectangle air-conditioning duct using RSM (Reynold Stress Model) and random trajectory particle model. Particle with nominal diameters of 10-200μm are simulated at each of three nominal air speed: 4m/s, 6m/s and 8m/s, respectively, in the cross-section sizes of 160×120, 500×250, 1000×320mm. In simulation, the paper compares and analyzes the influence factors of particles deposition in volume surface ratio of the given duct. The results show that: 1) particle deposition velocity increases with volume surface ratio; 2) As the inlet air speed increasing, when the particles deposited to floor and vertical wall, the image of dimensionless deposition velocity Vs dimensionless relaxation time shows a coincident trend when the duct cross-section sizes are 500×250, 1000×320mm, but has great differences with the image of 160×120mm.

Abstract: In the paper, a 1-D unsteady mathematical model is used to analyze the cooling process of high temperature sinter. The modeling result is compared with measured data, and the agreement is good. The effect of sinter particle size and void fraction on the cooling process of the annular cooler has been investigated.