Articles techniques et présentations

铁芯电抗器作为电力系统中重要的基础设备之一，具有漏磁小、节省空间等优点，因此在新能源和城市配电系统中得到广泛应用。但其运行中产生的噪声严重污染周边环境，而且电抗器振动过大对其自身正常运行也会构成威胁。本文在磁致伸缩效应和麦克斯韦方程相关理论研究基础上，采用COMSOL Multiphysics®多物理场仿真软件，通过AC/DC模块、声-固模块对三相电抗器铁芯的振动噪声进行研究。首先从多物理场耦合的角度，定义瞬态计算条件，然后在瞬态磁场的基础上加上声场和固体力场来建立三维物理模型，最后通过多物理场的耦合计算，得到电抗器铁芯振动位移和声压场分布 ... En savoir plus

微波化学反应的研究，一般要求实验装置要具有尺寸小、工作频带等特点，基于这种要求，近年来一种同轴式的微波反应器应运而生。本文基于COMSOL Multiphysics® 软件，对两种不同结构的同轴式微波反应器进行对比分析。结构主体是由外导体和内导体形成的同轴腔体，内外导体由金属材料构成可承受一定的高压反应。反应器一端为短路面，另一端结构一填充了截锥形聚四氟乙烯插件，结构二为填充了一定厚度的柱形聚四氟乙烯。我们建立了两种结构的二维轴对称模型，通过电磁波-频域接口、层流接口以及流体传热接口对其进行模拟计算，探究不同介质下反应器的加热效果。数值仿真结果如图2、图3、图4所示 ... En savoir plus

Atomic layer deposition(ALD) is one proven method to deposit ultra-thin films. ALD is advantageous for its atomic-level thickness control and conformity; leading to high quality films. Slow deposition rates for conventional ALD contribute to the impracticality of utilization of this ... En savoir plus

We investigate a prototype concept of a back-up electricity device where we use liquid formic acid (FA) to produce a mixture of carbon dioxide (CO2) and hydrogen (H2) which is used in a PEM fuel cell, Fig. 1. In the fluidized bed reactor the liquid FA is decomposed to a gaseous mixture ... En savoir plus

Convective transport of macromolecules or micro and nanoparticles in microsystems are usually predicted by solving the Navier Stokes equations for the carrier fluid and a concentration equation for the diffusing species. In the case of isolated particles or complicated geometries with ... En savoir plus

Recently, increasing availability of natural gas, due to the shale gas, raises the attention to the conversion of methane. Methanol-to-Hydrocarbons reaction (MTH) plays an important role in this route where methanol synthesized through syngas is converted into hydrocarbons, such as ... En savoir plus

In a water based electrolytic polishing process, the formation of molecular hydrogen at the cathode is unavoidable and it can contribute to the formation of surface defects at the anode side. This paper presents the work to model and simulate the molecular hydrogen flow inside radio ... En savoir plus

Chemicals are an integrated part of our daily life. While chemicals are significant contributor to a nation’s economy, sound management of chemical production is essential for environmentally friendly operation without maximizing operational costs. Next generation technologies must be ... En savoir plus

Hydrogen has great potential to be the fuel of the future through utilization in fuel cells, but it is rarely found naturally and must be produced in energy-intensive processes. Steam reforming, the process of heating natural gas and steam in the presence of a catalyst to drive a ... En savoir plus

During Physical Vapor Transport (PVT) growth of single 4H-SiC crystal and subsequent cooling down, thermal stresses lead to the multiplication of dislocations that are non-desirable for the semiconductor applications of this material. These dislocations induced by thermal stresses could ... En savoir plus