JGC has been developing a simulation method to predict solid deposition and pressure drop of slurry flows in pipelines with a shortened computation time. In this article, some case studies for validation of simulation methods by comparing the results of simulation with those of experiments are described. In addition, we have pointed out some considerations for the CFD simulation of slurry behavior.

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Solid-liquid mixing in a stirred vessel is widely used in chemical industrial processes, such as crystallization, leaching and chemical reaction by using solid catalysis. In these processes, control of sedimentation of particles on bottom is important to maximize efficiency of the chemical reaction and to prevent particle agglomeration. And particle collision with impeller blades often induces attrition and breakage of particles and erosion of the impeller blade. The mechanism of particle suspension from the vessel bottom and particle collision with impeller blade are not sufficiently understood, mainly because of the difficulties in experiments for characterizing detailed particle behavior.
  In this study, the relation between particle rising behavior from a vessel bottom and liquid flow around bottom was clarified by using Computational Fluid Dynamics (CFD) coupled with the Lagrangian simulation of each particle motion. The results show that a common relation of four steps exists between particle rising behavior and fluid flow around bottom among different type of stirred vessels. That is (i) formation of stagnant region on bottom, (ii) sweeping of particles until the stagnant region, (iii) inducement of upward flow above the stagnant region, (iv) particles are caught up in the upward flow. And the particle collision behaviors with impeller blades, such as collision velocity and collision point distribution, were quantified. The results show that, on the front (loading) face of impeller blade, particle collision with large collision velocity concentrates along the blade edge. On the back face, particle collisions mainly occur around the center of blade face.

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Petroleum refinery is an industrial plant where crude oil is processed and refined into more useful products such as gasoline, diesel fuel, kerosene and liquefied petroleum gas. Fluid catalytic cracking (FCC) is one of the most important conversion processes in a petroleum refinery, it also occupies very significant position in the refinery due to its economic benefits. RFCC is an extension of conventional FCC process, processing the heavier feedstock, and RFCC technology got great development around the reaction system, including the feeding atomization, quick separation of oil vapor and spent catalysis, steam stripping of high efficiency, temperature control of reaction as well as the innovation of riser reactor. This report shows the typical characteristics of RFCC process and introduces the results of several numerical studies.

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The authors are aiming at the development of a low power two-fluid-type atomizing system which can generate a large flow rate of fine liquid droplets, i.e., mists. In the present paper, the outline and the performance of the system studied to date in Kumamoto University are described together with its application to the mist cooling in a greenhouse and the reduction of smoke and harmful gas, say CO₂, by the adsorption by the mists.

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The present review provides a brief introduction to the capillary bridge force, which frequently appears and plays an important role in multiphase flows containing solid bodies. We explain the fundamentals and formulation of the capillary bridge force as well as its importance over other forces such as the van der Waals force and the electrostatic force. Also, we give some examples of the capillary bridge forces that are hardly recognized but appear in the real systems.

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If the flow channel in the PEFC separator is plugged with the liquid product water, pressure loss increases and the flow is destabilized to cause serious deterioration of the power generation performance. It may be probable that occurrence of the channel plugging can be avoided if the surface wettability of the channel wall is circumferentially non-uniform. In this work, systematic pressure drop measurements were carried out for the gas-liquid two-phase flow in small rectangular channels of various wettability distributions. It was found that the fluctuation of pressure loss that is frequently encountered in uniform wettability channels can dramatically be mitigated by the use of the flow channel of circumferentially non-uniform wettability.

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