Modeling the Drying Process of Porous Catalysts: Impact of the Pore Size Distribution.

The distribution of catalytically active species in heterogeneous porous catalysts strongly influences their performance and durability in industrial reactors. A drying model for investigating this redistribution was developed and implemented using the finite volume method. This model embeds an analytical approach regarding the permeability and capillary pressure from arbitrary pore size distributions.

Direct Numerical Simulation of Reactive Fluid-Particle Systems Using an Immersed Boundary Method.

In this paper, direct numerical simulation (DNS) is performed to study coupled heat and mass-transfer problems in fluid-particle systems. On the particles, an exothermic surface reaction takes place. The heat and mass transport is coupled through the particle temperature, which offers a dynamic boundary condition for the thermal energy equation of the fluid phase.

Direct Numerical Simulation of Fluid Flow and Mass Transfer in Particle Clusters.

In this paper, an efficient ghost-cell based immersed boundary method is applied to perform direct numerical simulation (DNS) of mass transfer problems in particle clusters. To be specific, a nine-sphere cuboid cluster and a random-generated spherical cluster consisting of 100 spheres are studied. In both cases, the cluster is composed of active catalysts and inert particles, and the mutual influence of particles on their mass transfer performance is studied.

Kinetic Monte Carlo simulation of the photodegradation process of polyester-urethane coatings.

A numerical method to simulate reactions in a cross-linked polymer is developed and applied to the photodegradation process of polyester-urethane clearcoats during artificial exposure in a Weather-Ometer. This coarse-grained simulation method, which is based on a kinetic Monte Carlo scheme, is verified with experimental data on the depth-resolved changes in optical properties and chemical composition that have been previously determined. By modelling the depth-dependency of physical processes that occur in the coating, such as the absorption of photons and the diffusion of oxygen, the experimentally observed evolution of depth gradients in chemical composition can be well described by the simulation.

Hierarchical multi-scale simulations of adhesion at polymer-metal interfaces: dry and wet conditions.

We performed hierarchical multi-scale simulations to study the adhesion properties of various epoxy-aluminium interfaces in the absence and presence of water. The epoxies studied differ from each other in their hexagonal ring structures where one contains aromatic and the other aliphatic rings. As aluminium is unavoidably covered with alumina, a cross-linked epoxy structure near an alumina substrate is created and relaxed by performing coarse-grained simulations.

Efficient Sampling of a Dual-Resolution Ensemble by Means of Dragging.

A method to simulate a dual-resolution ensemble for molecular systems is introduced. The dual-resolution system is characterized by an atomistic Hamiltonian and coarse coordinates connected by linear springs to this atomistic system. A 'dragging' update scheme based on an idea of Neal (Neal, R.