A. de Niet, A. van Nieuwenhuijzen, and A. Geilvoet
Witteveen+Bos, Deventer, The Netherlands
Clarifiers are used to separate sludge and water in waste water treatment plants. In this paper we analyze a malfunctioning clarifier using the mixture model. We are able to receive model results that are reasonably close to measurements from the real clarifier. With the model we can explain the bad separation of water and sludge in the clarifier. Engineers have proposed several actions in order ...
Research & Technology
Rick has a BS in Physics, a ScM in Geological Sciences, and a PhD in Physics. He worked at Air Force Geophysics Laboratory, Conoco Petroleum Exploration Research, and, since 1989, has been at the DuPont Experimental Station. In this industrial setting, Rick has had opportunity to work on a great diversity of problems ranging from traditional engineering studies, using commercial finite-element ...
T. Gulati, A. Datta
Cornell University, Ithaca, NY, USA
When rice is subjected to intense heating, it results in rapid evaporation of liquid water to vapor. As a consequence, large pressures are generated within the kernel in a span of 15s resulting in large volume changes causing the kernel to puff rapidly. Under suitable conditions, the ratio of initial volume to volume after puffing could be as high as 10. Rice puffing process is a complex ...
王威 , 周超 ,
微纳米马达是一种能将周围环境的能量转化为自身自主运动的新型智能仿生材料，其在药物的运输与释放，低维材料的合成以及软物质研究中有着重要的应用。基于自电泳的双金属棒马达是研究时间最长的一类马达，它有着与自然界中类似的自组装和群体行为的特性。但是其运动机理复杂且涉及到多个物理场的紧密耦合，这就为其进一步的研究和应用带来了一定的困难。 COMSOL Multiphysics® 可以方便地进行多物理场的模拟。图(1)展示了双金属棒的自电泳机理， 由于棒两端的化学反应造成了带电离子浓度的分布不均匀，进而产生自生电场驱动马达运动。其中传质过程、流体流动以及电场形成相互影响，环环相扣。基于以上物理过程，我们对 COMSOL 中稀物质传递，静电和蠕动流接口进行了有效的耦合，从而实现了马达周围离子场，电场和流场的模拟(图2)，在此基础之上，我们研究了马达的运动速度(图3) ...
D. Baldissin and D. Lombardo
Compumat S.r.l., Torino, Italy
A two-dimensional mathematical model for the absorption and desorption of H2 in LaNi4.8Al0.2 was developed and experimentally validated. The model is composed of an energy balance, a mass balance and a momentum balance. These differential equations are numerically solved by means of the finite element method using the software COMSOL Multiphysics®. From a comparison between theoretical ...
Numerical Simulation of Kinetic Interface Sensitive Tracer in Experiment with COMSOL Multiphysics® Software
F. Sun , A. Tatomir , F. Maier , M. Sauter 
 University of Goettingen, Goettingen, Lower Saxony, Germany
 Comsol Multiphysics GmbH, Goettingen, Lower Saxony, Germany
The kinetic interface-sensitive tracers (KIS tracers) are used to give a partial picture of the spreading, mixing and plume migration of supercritical carbon dioxide (scCO2) in the deep saline aquifer by estimating the interfacial areas between scCO2 and brine during the injection of scCO2. To get a better understanding of the KIS tracer reaction and transport processes in the two-phase flow ...
F. Maier, P. Oberdorfer, I. Kocabas, I. Ghergut, M. Sauter
Dpt. Applied Geology, Center of Geosciences, Georg-August-University, Göttingen, Germany
Petroleum and Natural Gas Engineering Department Batman, Batman University, Batman, Turkey
We compare the output of 2D single fracture models as well as analytical solutions of the problem. The temperature signal is evaluated with the heat transfer mode while the flow field is assumed to exhibit Darcy flow everywhere. The problem is time-dependent so we have to take into account a change in the boundary conditions from a Dirichlet to a Neumann condition which is activated at the time ...
O. Rouaud, T. Pham
LUNAM Université, ONIRIS, CNRS, GEPEA, UMR, Nantes, France
University of New South Wales, Sydney, Australia
A mathematical model is developed to determine the weight loss and the freezing rate during the freezing of unwrapped foodstuffs. The model allows comparing two freezing processes; the first uses nitrogen gas at -80°C and the second uses cold air. The model includes thermophysical properties that are temperature dependent to take into account the ice formation. The time step has to be chosen ...
A Multiphase Porous Medium Transport Model with Distributed Sublimation Front to Simulate Vacuum Freeze Drying
A. Warning, J. M. R. Arquiza, A. K. Datta
Cornell University, Ithaca, NY, USA
A continuum, porous medium formulation with non-equilibrium sublimation was developed and validated for freeze drying without and with uniform microwave volumetric heating. The model incorporates the effect of Knudsen flow at low pressure and low permeability freeze drying. The distributed, non-equilibrium sublimation demonstrated that the sublimation front is a sharp boundary for high ice ...
COMSOL Multiphysics for Efficient Solution of a Transient Reaction-Diffusion System with Fast Reaction
M.K. Gobbert, A. Churchill, G. Wang, and T.I. Seidman
Department of Mathematics and Statistics, University of Maryland, Baltimore County, Baltimore, Maryland, USA
A reaction between chemical species is modeled by a particular reaction pathway, in which one reaction is very fast relative to the other one. The diffusion controlled reactions of these species together with a reaction intermediate are described by a system of three transient reaction diffusion equations over a two-dimensional spatial domain. In the asymptotic limit of the reaction parameter ...