F.T. Wandschneider, M. Küttinger, P. Fischer, K. Pinkwart, J. Tübke, H. Nirschl
Fraunhofer-Institute for Chemical Technology, Pfinztal, Germany
Karlsruhe Institute for Technology, Karlsruhe, Germany
A two-dimensional stationary model of a vanadium oxygen fuel cell is developed in COMSOL Multiphysics®. This energy storage device combines a vanadium flow battery anode and an oxygen fuel cell cathode. The oxygen reduction reaction generates additional water, leading to a degradation of the catalyst performance over time. A logistic function is introduced to the Butler-Volmer equation in order ...
Mahecha-Botero, A., Elnashaie, S.S.E.H., Grace, J.R., Lim, C.J.
Department of Chemical and Biological Engineering, University of British Columbia, East Mall, Vancouver, BC, Canada
COMSOL (formerly FEMLAB) is being utilized to solve partial differential equations simulating fluidized bed reactors as part of the development of a novel generalized fluidized-bed catalytic reactor model. Simulations are carried out to account for complex dynamic transport and hydrodynamic phenomena such as: heat and mass axial and radial anisotropic dispersion, temperature and pressure ...
S. Gunsekaran , R. C. Thiagarajan
ATOA Scientific Technologies Private Limited, Bangalore, India
Multiphysics Simulations of Physico-chemical and Biological Treatment of wastewater is increasing due to the demand for cost efficient plant design and utilization. Among the many processes, a thorough understanding of the settling behavior of an activated granular sludge in the secondary settler of an Effluent Treatment Plant (ETP) is critical for the plant designers to determine the efficiency ...
S. Singer, W. H. Green
Massachusetts Institute of Technology, Cambridge, MA, USA
Transient, two-dimensional (axisymmetric) simulations of a cigarette subject to realistic static and forward smoldering cycles were performed. The computational domain consists of a porous packed bed of tobacco and a filter surrounded by a thin, porous paper and a region of surrounding air. The governing equations include overall mass conservation, momentum conservation, conservation equations ...
The Effect of Electrolyte Flow Slots in Tooling Electrodes on Workpiece Surface Finish in Electrochemical Machining
Oregon State University, Corvallis, OR, USA
Electrochemical machining (ECM) uses electrolysis to precisely remove material at high rates. ECM has many advantages over conventional machining: no tool wear, no induced mechanical or thermal stresses, high removal rates virtually independent of material hardness or strength, and excellent surface finishes. However, challenges can arise during the design of the tooling electrode when ...
Diffusion and Reaction in Fe-Based Catalyst for Fischer-Tropsch Synthesis Using Micro Kinetic Rate Expressions
A. Nanduri, P. L. Mills
Department of Chemical & Natural Gas Engineering, Texas A&M University, Kingsville, TX, USA
Fischer-Tropsch synthesis (FTS) is a highly exothermic polymerization reaction of syngas (CO+H2) in the presence of Fe/Co/Ru-based catalysts to produce a wide range of paraffins, olefins and oxygenates, often known as syncrude. Multi-Tubular Fixed Bed Reactors (MTFBR) and Slurry Bubble Column Reactors (SBCR) are widely employed for FTS processes. The scale-up of MTFBR is complicated by the ...
A. Malachowska, L. Pawlowski , A. Ambroziak , M. Winnicki , P. Sokolowski
University of Limoges, Limoges, France
Wroclaw University of Technology, Wroclaw, Poland
This paper studies oxide forming on titanium, during cold gas dynamic spraying with air. This is a quite new spraying method, which can be used to spray material having high affinity for oxygen. The model allows for the diffusion of oxygen through the oxide layer, reaction on the oxide-titanium interface and expansion of oxide, due to difference in molar density. It was implemented in COMSOL ...
W. Beckert, M. Dannowski, L. Wagner, J. Adler
Fraunhofer IKTS, Dresden, Germany
The 3D unit cell model approach offers an efficient tool to analyze the influences of geometrical design (channel shape and arrangement, filter length, wall thickness) and filter material properties (permeability, soot loading characteristics) on the performance of ceramic particle filter structure in the soot loading process, assessed by pressure loss and soot loading capacity. It does correctly ...
Effects of Flow and Diffusion on Blood Coagulation in Platelet Poor Plasma: a Two-way Coupling Between Hemodynamics and Biochemistry
D. Magnabosco[1,2], H. van Ooijen, B. Bakker, R. van den Ham
Politecnico di Milano, Milan, Italy
Philips Research, Eindhoven, The Netherlands
Enzyme reactions, blood flow and diffusion in human vasculature play interacting and fundamental roles in blood coagulation. In this complex mechanism, the balance between blood and clot is a delicate equilibrium, whose tight regulation is vital to avoid pathologies such as bleeding and thrombosis. The secondary hemostasis triggered by tissue factor in platelet poor plasma is studied up to fibrin ...
V. Memoli, and A. Cammi
Department of Nuclear Engineering, Politecnico di Milano, Milan, Italy
The moderator temperature coefficient (MTC) plays an important role within power thermal reactor dynamics. In order to run a reactor safely, a negative moderator coefficient temperature is necessary to reach stability during changes in temperature that can be caused by a step insertion of reactivity. Thus, MTC calculation is a key point in the reactor design process. The aim of the present work ...