Direct numerical simulations of homogeneous isotropic turbulence are used to investigate the effects of turbulence on the transport of particles in gas flows or bubbles in liquid flows. The inertia associated with the bubbles or the particles leads to locally strong concentrations of these in regions of instantaneously strong vorticity for bubbles or strain-rate for particles. This alters the a...

The microstructure plays a key role in the mechanical properties of hyper-eutectic Al-Si alloys. In this study, we investigate microstructural evolution rheo-die-casting (RDC) on Al-15Si-4Cu-0.5Mg alloy using rotational barrel system. Our findings demonstrate that higher speed and pouring temperature reduce size roundness primary Si particles semisolid slurry. Additionally, during RDC, dendriti...

Delivery systems with a solid dispersed phase can be produced in a melt emulsification process. For this, dispersed particles are melted, disrupted, and crystallized in a liquid continuous phase (melt emulsification). Different to bulk crystallization, droplets in oil-in-water emulsions show individual crystallization behavior, which differs from droplet to droplet. Therefore, emulsion droplets...

A Large Eddy Simulation approach for Eulerian-Eulerian dispersed two-phase flow is presented. It is shown that not only a Sub-Grid Scales term modeling the unresolved field in the mesoscopic momentum transport equation of the dispersed phase, but also a stress term modeling the Random-Uncorrelated Motion is needed. Simulations of a non-homogeneous particle laden turbulent gas flow allow to comp...

Dispersed multiphase turbulent flows are present in many industrial and commercial applications like internal combustion engines, turbofans, dispersion of contaminants, steam turbines, etc. Therefore, there is a clear interest in the development of models and numerical tools capable of performing detailed and reliable simulations about these kind of flows. Large Eddy Simulations offer good accu...

This study examined the mass transfer performance in a pulsed perforated-plate extraction column with diameter of 50 mm using two different liquid systems. Mass transfer coefficients have been interpreted in terms of the axial diffusion model. The effects of pulsation intensity and dispersed and continuous phase velocities on the mass transfer performance have been investigated. Three different...

single-particle process Consider a single particle of volume V ( t ) at time t which undergoes random, discontinuous “erosion” to smaller sizes in accord with the probabilistic law: Pr( V ( t + d t ) I u I V ( f ) = u’ 1 = B ( u I u’ )dt We let F( u, t ) be the cumulative distribution function for the size of the single particle undergoing random erosion. Suppose that the cumulative probability...

Transport of emulsions in porous media is relevant to several subsurface applications. Many enhanced oil recovery (EOR) processes lead to emulsion formation and as a result conformance originating in the flow of a dispersed phase may arise. In some EOR processes, emulsion is injected directly as a mobility control agent. Modeling the flow of emulsion in porous media is extremely challenging due...

This paper describes a new design of a local four-sensor probe which was used to measure the local velocity vector of the dispersed phase in a bubbly gas-liquid two phase flow. Based on the four-sensor probe signals, a new signal processing technique was also introduced. Reference data was obtained using high speed cameras to determine the optimum value for the threshold voltages relevant to th...

We explore the microfluidic generation of bubbles in a flow-focusing junction using a pressure-controlled device rather than the more common flow ratecontrolled devices. This device is a prototype for extending microfluidic drop generation methods to molten polymers. We show that the bubble generation process is highly sensitive to pressure: small changes in pressure induce large changes in bub...