the steps taken in designing a loop reactor for bulk propylene polymerization are discussed. the roles played by several parameters like particle growth factor, catalyst activity and solid fraction on reactor volume at different operating conditions are investigated. at first, based on a fixed production capacity and specific rate of catalyst, reactor volume is determined. next, the length and ...

In this study, the effect off adding SiO2 nanoparticles on the viscosity of base fluid is investigated experimentally. Base fluids are chosen among common heat transfer fluids such as ethylene glycol, transformer oil and water. In addition different volume percentages of ethylene glycol in water are used as ethylene glycol-water solution. In every base fluid different volume fractions of SiO2 n...

We are currently studying microstructural responses to diffusion-limited coarsening in twophase materials. A mathematical solution to late-stage multiparticle diffusion in finite systems is formulated with account taken of particle-particle interactions and their microstructural correlations, or “locales”. The transition from finite system behavior to that for an infinite microstructure is esta...

Gas-phase velocity fluctuations in fixed particle beds and freely evolving suspensions are quantified using particle-resolved direct numerical simulation (PR-DNS). The flow regime corresponds to homogeneous gas-solid systems typically encountered in fluidized bed risers, with high solid to gas density ratio and particle diameter being greater than the dissipative length scales. The contribution...

Microgel particles with a soft repulsive interaction potential are investigated with particle tracking methods to study the phase behavior of soft-sphere systems. The use of poly(N-isopropylacrylamide) particles allows the effective volume fraction of a sample to be tuned via thermal modulation without altering the particle number density. This allows for investigation of the phase behavior of ...

We study the form factor of thermoresponsive microgels based on poly(N-isopropylacrylamide) at high generalized volume fractions, ζ, where the particles must shrink or interpenetrate to fit into the available space. Small-angle neutron scattering with contrast matching techniques is used to determine the particle form factor. We find that the particle size is constant up to a volume fraction ro...

Ultra-fine particle coagulation by Brownian motion at high concentration in planar jet flow is simulated. A Taylor-Series Expansion Method of Moments is employed to solve the particle general dynamic equation. The volume fraction gets high value, very closes to that at the nozzle exit. As the vortex pairing develops, the high volume fraction region rolls out and mixes with the low value region....

We study ionic microgel suspensions composed of swollen particles for various single-particle stiffnesses. We measure the osmotic pressure π of these suspensions and show that it is dominated by the contribution of free ions in solution. As this ionic osmotic pressure depends on the volume fraction of the suspension ϕ, we can determine ϕ from π, even at volume fractions so high that the microge...

The macroscopically emergent rheology of suspensions is dictated by details of fluid-particle and particle-particle interactions. For systems where the typical spatial scale on the particle level is much smaller than that of macroscopic properties, the scales can be split. We present a heterogeneous multiscale method (HMM) approach to modeling suspension flow in which at the macroscale the susp...

We rely on the lattice element method to simulate and analyze the stress fields at subparticle scales in two-dimensional granular solids composed of particles of variable stiffness together with an interstitial matrix of variable volume fraction. We find that the contact force distributions as approached from the subscale stresses are similar to those obtained from a particle-scale discrete ele...