When particles are transported in pipelines, they acquire electrostatic charges as they come into contact with the pipe wall. Charged particles can cause problems such as particle agglomeration, blockage, and explosion. Understanding the particle charge can help to prevent these issues. This study investigates a technique for predicting the particle charge in a straight pipe of any given length, as well as the pipe length at which electrostatic equilibrium occurs, through experimentation in a short 1m pipe section.Experimentation with five different types of particles and four pipe wall materials at longer pipe lengths were used to validate the technique. This predictive technique is applicable to a range of particle shapes and sizes under the restriction that charge transfer is due to impact charging. Heading:Particle technology and fluidization

In this study, a Schulze ring shear tester and the discrete element method (DEM) are employed to investigate the effect of polydispersity on the binary shear flows. Both experimental results and DEM simulations show that the preshear stresses are greater for binary blends than for monodispersed particles. The flowability of these mixtures is strongly affected by the solid fraction, with minimal flow function values correlating to maximum packing fraction. However, minimum flow function values are not observed at the same packing fractions where the maximum preshear stress occurs. Using DEM, it is demonstrated that the decrease of angular velocity of larger particles due to the addition of small adhesive particles reduces and the fraction of large‐small particle contact both make contributions to shear stress difference. A mechanism is proposed to quantify the effects of these two factors.

Particle morphology plays an important role in pulmonary drug delivery. Not only does particle shape affect how particles flow and deposit, the shape also influences the drug release rate from the particles. In this work, a semi-theoretical relationship is developed to describe deposition efficiency as a function of fluid and particle properties, incorporating the effect of particle shape. For the 10 different particle types studied (with aerodynamic diameters between 1 and 10 µm), three key deposition mechanisms are identified. All particles deposit through inertial impaction, and additionally deposit via sedimentation or diffusion, depending on the particle specific momentum.

In this study, a Schulze Ring Shear Tester and the Discrete Element Method (DEM) are employed to investigate the effect of polydispersity on the binary shear flows. Both experimental results and DEM simulations show that the pre-shear stresses are greater for binary blends than for monodispersed particles. The flowability of these mixtures is strongly affected by the solid fraction, with minimal flow function values correlating to maximum packing fraction. However, minimum flow function values are not observed at the same packing fractions where the maximum pre-shear stress occurs. The powder friction has a slightly higher contribution to powder strength than powder adhesion, and the frictional component follows the same trend as shear stress with mixture composition. Using DEM, it is demonstrated that the addition of small adhesive particles reduces the averaged angular velocity of the larger particles, which makes a contribution to the larger shear stress for binary blends.