E. Bozelie, P. Bruins
Saxion University Enschede, Enschede, The Netherlands
In heating upgrades, most attention is paid to the boiler. When upgrading to HR++-boilers (eff of 107%) however, difficulties may occur since the high efficiency boilers are designed for water temperatures around 40°C, while the old radiators are designed for water temperatures higher than 60°C. The resulting mismatch may lead to reduced performance, a larger carbon footprint and increased ...
COMSOL Multiphysics® Simulation of Energy Conversion and Storage Concepts Based on Oxide Crystals - new
C. Cherkouk, M. Zschornak, J. Hanzig, M. Nentwich, F. Meutzner, M. Urena, T. Leisegang, D. C. Meyer
Institute of Experimental Physics, Technische Universität Bergakademie, Freiberg, Germany
Fraunhofer-Technologiezentrum, Freiberg, Germany
A mathematical model based on a finite element method (FEM) is presented as an initial approach for a system converting waste heat energy into chemical energy. This system consists of a pyroelectric LiNbO3 plate placed into a cylinder which undergoes a laminar water flow with an appropriate periodic heat source. It solves the heat transfer equation in non-isothermal flow, where the density of ...
C. Grau Turuelo, C. Breitkopf
Technische Universität Dresden, Dresden, Germany
The void shape evolution of silicon is a process driven mainly by surface diffusion which leads to a geometrical transformation of trenches etched in silicon wafers due to surface energy minimization. The temperature, the ambient gas and the annealing time affect the velocity of the process. The use of custom PDEs in COMSOL Multiphysics® software and the Level-Set method provide a good base ...
Thermal Natural Convection Simulations with COMSOL Multiphysics® in Comparison with Measurements - new
H. van Halewijn
Fontys University of Applied Physics, Eindhoven, The Netherlands
In a laboratory setup a horizontal rod is heated on one side. By natural convection a stable temperature pattern is developed. Using the Nusselt formulation of the natural convection of cylindrical rods, the temperature distribution can be calculated. Only a good match of the simulations and the measurements can be reached when taking into account all the non-linear physics in the system. In ...
P. Vincent, E. Humphreys
College of Earth, Ocean, & Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
Department of Geological Sciences, University of Oregon, Eugene, OR, USA
Introduction: Lithospheric delamination beneath the western U.S. is believed to be the driving mechanism responsible for the evolution of magmatic and topographic features observed at the surface in the western U.S.. This process requires hot asthenosphere to be in contact with the underside of cold sub-crustal lithosphere and believed to be initiated by the Yellowstone hot spot plume that due ...
H. Karakuzu, M. Dubov, S. Boscolo
 Aston University, Birmingham, UK
We present an optimization procedure to improve the propagation properties of the depressed-cladding, buried micro-structured waveguides formed in a z-cut lithium niobate (LN) crystal by high repetition rate femtosecond (fs) laser writing. It is shown that the propagation wavelength for which the confinement losses of ordinary (O) and extraordinary ordinary (E) polarizations are below 1 dB/cm ...
M. Algappan, P. C. Chakravarthi, R. Keerthana, S. Mangayarkarasi, A. Kandaswamy
PSG College of Technology, Coimbatore, Tamil Nadu, India
A medical ventilator is an imperative device used to save life by delivering an assortment of air and oxygen into and out of the patients’ lungs to administer breathing or to assist obligatory breathing. The commercially available diaphragm based pressure sensors made up of silicon measure the air and oxygen flow. The proposed work utilizes the Piezo electric material for the pressure range ...
Numerical Simulation of Carbon Steel Corrosion Exposed to Flowing NaCl Solutions Through an Annular Duct - new
A. Soliz, K. Mayrhofer, L. Caceres
Department of Interface Chemistry & Surface Engineering, Max-Planck-Institut für Eisenforschung, Düsseldorf, Germany
Department of Chemical Engineering, University of Antofagasta, Antofagasta, Chile
A three-dimensional mathematical model under stationary conditions have been established to understand the corrosion of carbon steel cylindrical samples immersed in flowing NaCl solution through an annular duct. The migration, diffusion and convection mass transfer mechanisms were solved using the Nernst–Planck equation coupled to the Navier-Stokes equation. A corrosion model based on the mixed ...
LIMCA技术是一种原位测量高温液态金属中杂质颗粒的方法。测量的原理为：在一个小孔内外设置一对电极，并且通以电流，这样可以在孔口附近形成一个电敏感区，当杂质经过电敏感区时，通过测量电压脉冲信号以检测杂质的信息。对硬质颗粒的LIMCA技术已经有了许多研究，但实际情况下有些颗粒如气泡是可变形的，这将损害LIMCA的精度。 模型使用了 COMSOL Multiphysics® 中的“层流两相流-相场”和“电磁场”模式，气泡和液态铝以相同的初始速度向相同方向运动，同时在液态导电金属中通以电流。由于流体和气泡是运动的，流动会受到洛伦兹力的影响，所以在流场中加入由电磁场计算得到的“mef.FLtzr”和“mef.FLtzz”作为体积力源项。同时流动结构的改变也会影响电磁场，两个物理场之间存在着强耦合，需要同时求解。 数值计算结果给出了在气泡变形情况下的流场、电磁场 ...
J. Burrow , A. Bond ,
 Quintessa Ltd, United Kingdom
The UK Advanced Gas-cooled Reactor fleet, operated by EDF Energy, utilize a graphite core consisting of a lattice of around 3000 annular bricks. Due to irradiation, oxidation and thermal effects, the bricks deform and loose mass as they age. Of key concern is the late-life behavior of the bricks, in particular the predicted time at which brick shrinkage reverses into expansion, generating large ...