This work extends existing multiphase-fluid SPH frameworks to cover solid phases, including deformable bodies and granular materials. In our extended multiphase SPH framework, the distribution and shapes of all phases, both fluids and solids, are uniformly represented by their volume fraction functions. The dynamics of the multiphase system is governed by conservation of mass and momentum within different phases. The behavior of individual phases and the interactions between them are represented by corresponding constitutive laws, which are functions of the volume fraction fields and the velocity fields. Our generalized multiphase SPH framework does not require separate equations for specific phases or tedious interface tracking. As the distribution, shape and motion of each phase is represented and resolved in the same way, the proposed approach is robust, efficient and easy to implement. Various simulation results are presented to demonstrate the capabilities of our new multiphase SPH framework, including deformable bodies, granular materials, interaction between multiple fluids and deformable solids, flow in porous media, and dissolution of deformable solids.

A moving bed reactor concept was introduced to the methanol to propylene process. To implement this concept, a modified kinetic model of MTP reaction on a special HZSM-5 pellet catalyst was developed; a moving bed reactor model in propylene yield platform period was proposed. Applying these two models, a two-stage moving bed in series with methanol quenched between stages was investigated. Water and part of the byproducts were recycled to the first moving bed reactor. Simulation results showed that the recycle of byproducts could increase the yield of propylene to 70%. The roles of higher hydrocarbons in the two reactors were different since they acted as reactants in the first moving bed while as products in the second one.

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We present a novel divergence free mixture model for multiphase flows and the related fluid‐solid coupling. The new mixture model is built upon a volume‐weighted mixture velocity so that the divergence free condition is satisfied for miscible and immiscible multiphase fluids. The proposed mixture velocity can be solved efficiently by adapted single phase incompressible solvers, allowing for larger time steps and smaller volume deviations. Besides, the drift velocity formulation is corrected to ensure mass conservation during the simulation. The new approach increases the accuracy of multiphase fluid simulation by several orders. The capability of the new divergence‐free mixture model is demonstrated by simulating different multiphase flow phenomena including mixing and unmixing of multiple fluids, fluid‐solid coupling involving deformable solids and granular materials.

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Due to the superior performance in thermal conductivity and mechanical strength, the foam SiC-supported ZSM-5 catalyst is favorable in fixed bed methanol-to-propylene (MTP) reactions, where the temperature distribution and pressure drop are strictly controlled. However, its performance and service life in multiple reaction–regeneration cycles has not been proved yet. Both the activity and selectivity of the catalyst will be tested in six reaction–regeneration cycles in a fixed bed reactor. In addition, the properties of the catalyst during the fourth cycle were characterized by various techniques (scanning electron microscopy, Brunauer–Emmett–Teller, 27Al nuclear magnetic resonance). The results show that, as the reaction progresses, the catalyst continuously deposits carbon, and the local high temperature of carbon burning during regeneration leads to the removal of aluminum from the zeolite framework. Therefore, the catalyst life in one single process increases first and then decreases. At the same time, the propylene selectivity also experiences rapid rising, steady rising, and rapid descent periods; the steady rising period is the best MTP reaction period of operation.

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