Simulation of the Transient Heating in an Unsymmetrical Coated Hot--Strip Sensor with a Sel

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机械专业SolidWorks英文参考及翻译

http://kkb.hhu.e e-mail: wse@.cn Water Science and Engineering, 2009, 2(1): 95-102doi:10.3882/j.issn.1674-2370.2009 .01.009Modeling in SolidWorks and analysis of temperature and thermal stress during construction of intake towerHong-yang ZHANG* †1, Tong-chun LI1, Zong-kun LI21. College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, P. R. China2. School of Water Conservancy and Environment Engineering, Zhengzhou University,Zhengzhou 450002, P R. ChinaAbstract:With a focus on the intake tower of the Yanshan Reservoir, this paper discusses themethod of modeling in the 3D CAD software SolidWorks and the interface processing betweenSolidWorks and the ANSYS code, which decreases the difficulty in modeling complicated modelsin ANSYS. In view of the function of the birth-death element and secondary development withAPDL (ANSYS parametric design language), a simulation analysis of the temperature field andthermal stress during the construction period of the intake tower was conveniently conducted. Theresults show that the temperature rise is about 29.934 〇C over 3 or 4 days. The temperaturedifferences between any two points are less than 24 ^. The thermal stress increases with thetemperature difference and reaches its maximum of 1.68 MPa at the interface between two concretelayers.Key words: SolidWorks; ANSYS;APDL; birth-death element; temperature field; thermal stress1 IntroductionMass concrete is widely used in civil and hydraulic engineering nowadays, and its thermal stress increasingly attracts attention during design and construction. It is necessary to analyze the temperature field and thermal stress of important mass concrete structures with both routine methods and the finite element method (FEM). Some researchers have done a large amount of simulation analyses using FEM software (Tatro 1985; Barrett et al. 1992; Kawaguchi and Nakane 1996; Zhu and Xu 2001; Zhu 2006), but difficulties in these methods remain. There are two main difficulties: (1) Most mass concrete structures are complex and difficult to model with FEM software. (2) Complete simulation is difficult with FEM software because of the complex construction processes and boundary conditions of concrete.The structure of the intake tower of the Yanshan Reservoir is complex. It is 34.5 m high and there is a square pressure tunnel at the bottom, the side length of which is 6 m. The intake tower was modeled in the 3D CAD software SolidWorks and imported into ANSYS with an interface tool. Then, using the APDL program, analysis of the temperature field and thermalThis work was supported by the Natural Science Foundation of Henan Province (Grant No. 511050100).†Corresponding author (e-mail: zhybryant@)Received Nov. 11, 2008; accepted Jan. 15, 200996 Hong-Yang ZHANG et al. Water Science and Engineering, Mar. 2009, Vol. 2, No. 1,95-102Fig. 2 Cross section stress during construction was conducted.2 Modeling in SolidWorks and interface processing between SolidWorks and ANSYS2.1 Modeling in SolidWorksSolidWorks is a CAD/CAE/CAM/PDM desktop system, and the first 3D mechanical CAD software in Windows developed by the SolidWorks company. It provides product-level automated design tools (Liu and Ren 2005).The outside structure of the intake tower is simple but the internal structure is relatively complex. Therefore, the process of modeling is undertaken from the inside to the outside. The integrated and internal models of the intake tower are shown in Fig. 1 and Fig. 2.Fig. 1 Integrated model2.2 Interface processing between SolidWorks and ANSYSANSYS is a type of large universal finite element software that has a powerful ability to calculate and analyze aspects of structure, thermal properties, fluid, electromagnetics, acoustics and so on. In addition, the interface of ANSYS can be used to import the CAD model conveniently (Zhang 2005), which greatly reduces the difficulties of dealing with complex models. The interface tools are given in Table 1.After modeling in SolidWorks, it is necessary to save the model as a type of Parasolid (*x_t) so as to import it into ANSYS correctly. Then, in ANSYS, the importing of the model is completed with the command “PARAIN, Name, Extension, Path, Entity, FMT, Scale” or the choice of “File^Import^PARA...” in the GUI interface. There are two means of importing: selecting or not selectin g “Allow Defeaturing”, the differences of which are shown in Fig. 3 and Fig. 4.⑴d rFig. 3 Importing with defeaturing Fig. 4Importing without defeaturing3 Analysis of temperature field of intake towerThe temperature analysis of the intake tower during the construction period involves aspects of the temperature field and thermal stress. The calculation must deal with the problems of simulation of layered construction, dynamic boundary conditions, hydration heat, dynamic elasticity modulus, autogenous volume deformation of concrete and thermal creep stress, which are difficult to simulate directly in ANSYS. APDL is a scripting language based on the style of parametric variables. It is used to reduce a large amount of repetitive work in analysis (Gong and Xie 2004). This study carried out a simulation analysis of the temperature field considering nearly all conditions of construction, using the birth-death element and programming with APDL.3.1 Solving temperature field principle3.1.1 Unsteady temperature field analysisThe temperature of concrete changes during the construction period dueto the effect of hydration heat of cement. This problem can be expressed as a heat conduction problem with internal heat sources in the area. The unsteady temperature field T(x,y,z,T) is written as (Zhu 1999):dT X f d2T d2T d2T=---- ---- 1--- 1 --dr c^yd:x2dy2dz2where 义 is the thermal conductivity of concrete, c is the specific heat of concrete, p is the density of concrete, 0 is the adiabatic temperature rise of concrete, and T is the age of concrete.In the 3D unsteady temperature field analysis, the functional form I e (T) iswhere AR is a subfield of unit e; AD is the area on surface D, which is only in boundaryHong-Yang ZHANG et al. Water Science and Engineering, Mar. 2009, Vol. 2, No. 1,95-102 97(3)where ? is the pouring time. The conversion between Q and 6 isadr cpThe boundary conditions involve the laws of interaction between concrete and the surrounding medium. When concreteis exposed to the air, the boundary condition is,5T、(4)-Mdn(5)T = 26.1 - 25.1cos284 (?-79) (6)units; P=——;P is the exothermic coefficient; the thermal diffusivity a =——;and T a is cp cpthe air temperature.3.1.2 Initial conditions and boundary conditions of concreteThe initial conditions are the distribution laws of the initial transient temperature of internal concrete. The calculated initial temperature of concrete is 10 ^.The index formula of hydration heat of cement isQ(?) =71 610[1 - exp(-0.36?)]where n is the normal direction. Both 7^ and P are constants or variables (Ashida and Tauchert 1998; Lin and Cheng 1997).During the maintenance period, the insulation materials of concrete are steel formworks and straws, and the exothermic coefficient of the outer surface is reduced as equivalent processing. The exothermic coefficients of the steel formwork and the straw are 45 kJ/(m2*h’C) and 10 kJ/(m2*h’C), respectively.Based on the local temperature during construction, the following formula can be fittedaccording to the temperature variation curve:3.2 Analysis of temperature field in ANSYSThe simulation scheme of layered construction, which is based on the real construction scheme, is shown in Table 2. The pouring days in Table 2 are all the total days of construction for each layer. A layer is not poured until the former layer is poured.98 Hong-Yang ZHANG et al. Water Science and Engineering, Mar. 2009, Vol. 2, No. 1,95-102Hong-Yang ZHANG et al. Water Science and Engineering, Mar. 2009, Vol. 2, No. 1,95-102 99temperatures and the temperature curves are given in Table 3 and Fig. 5, respectively.Fig. 5 Maximum temperature curves Fig. 5 shows that the maximumtemperature of each layer occurs on the 3rd or 4th day after pouring, and then the temperature decreases with time, which is consistent with related literature (Lin and Cheng 1997; Luna and Wu 2000; Wu and Luna 2001). In Fig. 5, the numbers of feature points from 2 to 8 are corresponding to their maximum temperature curves from Nodetemp 2 to Nodetemp 8, and the curve of Nodetemp 9 is the air temperature curve. Feature point 8, the maximum temperature of which is 29.934 °C, occurring on the 206th day of the total construction period, shows the maximum temperature rise during the construction period. Feature point 4, the coordinates of which are (16.4, 16.0, 5.0), shows the maximum temperature difference of 23.534 °C.4 Analysis of thermal stress of intake towerExpansion or contraction of the structure occurs during heating and cooling. If the expansion or contraction of different parts is inconsistent, then thermal stress occurs. The indirect method was adopted in this study: the temperature of nodes was first obtained in analysis of the temperature field, and then applied to the structure as a body load.4.1 Selection of calculating parametersThe parameters of concrete are given in Table 4. The elasticity modulus is尽=3.6x1010[1-exp(-0.40’。

工业相机自热引起像点漂移模型与补偿方法

账对像点坐标的影响，建立图像像点漂移补偿模型。大量实验表明，利用模型补偿后的像点漂移误差
从0.4~0.6 p i x e l 降低到0.1〜0.2 pixel,与采用硬件热控方式达到的像点漂移抑制效果相当。但是相对
件，导致相机整体产生热变形，热变形引起相机参数产生变化，进而影响测量精度，这种效应称为相机自热效应。S m i t h 和 C o p e [ll]将相机放在冰箱中降低其内部温度来研究温度对相机参数影响，得出温度变化 1 尤，镜头焦距变化 1 n m 的结论。 P o d b r e z n i k 和 P o t o c n i k M 以低成本相机为研究对象，建立温度变化对焦距、主点和畸变参数的影响模型，得出随着被测物与摄像机之间距离的增加，温度影响逐渐减小的结论。M .D a a k i r 等人[13]发现相机热变形对相机内部参数 (焦距、主点）的影响，并认为传感器温度变化是产生该影响的主要原因。L i p i n g Y u 和 Gilles L u b i n e a u [14】基于简化的立体视觉模型，仿真分析摄像机自热对三维坐标、位移和应变测量的影响，得出相机温度变化对立体数字图像相关技术的影响。P a n 等 [15]在针孔模型上研究温度变化对立体测量的影响，发现应变测量误差约为30~50 n e / t 。在相机热致变形研究上，多采用实验的方式研究温度与图像整体膨胀变化的关系。M a 等人％通过对相机传热过程进行分析，发现相机达到热平衡时温度升高约1 0 尤,相机镜头与传感器平面产生不同的平移量，得出相机组件温度与图像膨胀的关系。Z h o u 等m 系统地研究了数码相机工作时的传热过程和温度特性，建立了相机热平衡时间和热平衡温度的模型。P a n 等人 1181通过研究温度变化对立体测量的影响，提出将相机预热达到热平衡后再进行视觉测量的方法。目前研究工作主要集中在相机传热过程与相机成像参数变化和温度变化的关系。关于像点漂移研究集中在漂移的现象，并未充分分析漂移产生的根本原因，而且尚未有漂移大小、方向与温度变化关系的合理解释。

瞬变流实时水力仿真软件开发

第二章：供热管网瞬变流计算原理及模型
瞬变流方程的解法——有限差分方程
• 有限差分法的主要解题步骤如下： • 1）建立微分方程 • 根据问题的性质选择计算区域，建立微分方程式，写出初始条件和边界条件。 • 2）构建差分格式 • 首先对求解域进行离散化，确定计算节点，选择网格布局，差分形式和步长；然后以有限差分代替无线微
第一章：绪论
• 瞬变流的研究历程
• 瞬变流的理论研究开始于十九世纪中叶。1850年Wilhelm Weber实测了瞬变流下管壁弹性对水锤波速的影响。在20世纪初，对于瞬变流理论开始进行大量的理论和实验研究。1902年Lereuzo Allive建立了瞬变流基本微分方程，并于1913年创立了水锤分析的算术法和图解法，奠定了水锤分析的理论基础。70年代后随着动态测量技术的发展，瞬变流理论研究进入了新时代。
• 瞬变流基本微分方程式是瞬变流计算的基础，电算法是依靠电脑程序来进行的，但是电脑程序不能直接运用瞬变流基本微分方程式来计算，需要将其转化为电脑程序能识别的有限差分方程才行。
第二章：供热管网瞬变流计算原理及模型
• 瞬变流计算模型的基本方程
• 供热管网属于有压管道，而有压管道中的瞬变流动应按可压缩流体的非定常流动来考虑，其基本微分方程包括连续性方程和运动方程，其推导过程满足以下条件：
小控制体 1—2，如图 2-1 所示：
• 液体从截面1—1流入，从截面 2—2 流出，两截面间距dx。设截面 1—1的面积为A，平均流速为V，液体密度为ρ。
Байду номын сангаас
第二章：供热管网瞬变流计算原理及模型
第二章：供热管网瞬变流计算原理及模型
第二章：供热管网瞬变流计算原理及模型
第二章：供热管网瞬变流计算原理及模型

蛇形管高压加热器集管结构的热弹性分析

２．ＳｈａｎｇｈａｉＡｕｘｉｌｉａｒｙＰｏｗｅｒＥｑｕｉｐｍｅｎｔＣｏ．，ＬＴＤ．，Ｓｈａｎｇｈａｉ２０００９０，Ｃｈｉｎａ）
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０概述
１高压加热器的高压腔室
发电厂的高压加热器（简称高加）是利用汽轮机抽汽加热锅炉（或蒸汽发生器）给水的装置。利用高加加热给水，可提高机组的热效率，并有助于机组的安全运行。高压加热器通常有２种结构型式，即Ｕ形管式和蛇形管式。
收稿日期：２０１８—０２—０８修回日期：２０１８—０５—２３国家科技支撑计划项目：２０１５ＢＡＡ０３Ｂ０１，课题为ＩＯ００ＭＷ级高效宽负荷率的超超临界机组的开发与应用。作者简介：陈宝星（１９７３一），男，工程师，毕业于华北电力大学，从事火力机组汽轮机运行及维护方面的工作。
中图分类号：ＴＫ２６４．９
文献标识码：Ａ
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焊接温度场和应力场的数值模拟

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沈阳工业大学硕士学位论文焊接温度场和应力场的数值模拟姓名：王长利申请学位级别：硕士专业：材料加工工程指导教师：董晓强 20050310沈阳工业大学硕士学位论文摘要焊接是一个涉及电弧物理、传热、冶金和力学的复杂过程。

焊接现象包括焊接时的电磁、传热过程、金属的熔化和凝固、冷却时的相变、焊接应力和变形等。

一旦能够实现对各种焊接现象的计算机模拟，我们就可以通过计算机系统来确定焊接各种结构和材料的最佳设计、最佳工艺方法和焊接参数。

本文在总结前人的工作基础上系统地论述了焊接过程的有限元分析理论，并结合数值计算的方法，对焊接过程产生的温度场、应力场进行了实时动态模拟研究，提出了基于ＡＮＳＹＳ软件为平台的焊接温度场和应力场的模拟分析方法，并针对平板堆焊问题进行了实例计算，而且计算结果与传统结果和理论值相吻合。

本文研究的主要内容包括：在计算过程中材料性能随温度变化而变化，属于材料非线性问题；选用高斯函数分布的热源模型，利用函数功能实现热源的移动。

建立了焊接瞬态温度分布数学模型，解决了焊接热源移动的数学模拟问题；通过改变单元属性的方法，解决材料的熔化、凝固问题；对焊缝金属的熔化和凝固进行了有效模拟，解决了进行热应力计算收敛困难或不收敛的问题；对焊接过程产生的应力进行了实时动态模拟，利用本文模拟分析方法，可以对焊接过程的热应力及残余应力进行预测。

本文建立了可行的三维焊接温度场、应力场的动态模拟分析方法，为优化焊接结构工艺和焊接规范参数，提供了理论依据和指导。

关键词：焊接，数值模拟，有限元，温度场，应力场沈阳工业大学硕士学位论文ＳｉｍｕｌａｔｉｏｎｏｆｗｅｌｄｉｎｇｔｅｍｐｅｒａｔｕｒｅｆｉｅｌｄａｎｄｓｔｒｅｓｓｆｉｅｌｄＡｂｓｔｒａｃｔＷｅｌｄｉｎｇｉｓａｃｏｍｐｌｉｃａｔｅｄｐｈｙｓｉｃｏｃｈｅｍｉｃａ／ｐｒｏｃｅｓｓｗｌｆｉｅｈｉｎｖｏｌｖｅｓｉｎｅｌｅｃｔｒｏｍａｇｎｅｔｉｓｍ，Ｍａｔｔｒａｎｓｆｅｒｒｉｎｇ，ｍｅｔａｌｍｅｌｔｉｎｇａｎｄｆｒｅｅｚｉｎｇ，ｐｈａｓｅ?ｃｈａｎｇｅｗｅｌｄｉｎｇＳＯｓｔｒｅｓｓａｎｄｄｅｆｏｒｍａｔｉｏｎａｎｄｏｎ，Ｉｎｏｒｄｅｒｔｏｇｅｔｈｉｇｈｑｕａｆｉｔｙｗｅｌｄｉｎｇｓｔｍｃｔｔｌｒｅ，ｔｈｅｓｅｆａｃｔｏｒｓｈａｖｅｔｏｂｅｃｏｎｔｒｏｌｌｅｄ．Ｉｆｃａｎｗｅｌｄｉｎｇｐｒｏｃｅｓｓｂｅｓｉｍｕｌａｔｅｄｗｉｔｈｃｏｍｐｕｔｅｒ，ｔｈｅｂｅｓｔｄｅｓｉｇｎ，ｐｍｃｅｄｕｒｅｍｅｔｈｏｄａｎｄｏｐｔｉｍｕｍｗｅｌｄｉｎｇｐａｒａｍｅｔｅｒｃａｎｂｅｏｂｔａｉｎｅｄ．ＢａｓｅｄＯｉｌｓｕｍｍｉｎｇｕｐｏｔｈｅｒ’Ｓｅｘｐｅｒｉｅｎｃｅ，ｅｍｐｌｏｙｉｎｇｎｕｍｅｒｉｃａｌｃａｌｃｕｌａｔｉｏｎｍｅｔｈｏｄ，ｔｈｉｓｐａｐｅｒｒｅｓｅａｒｃｈｅｒｓｙｓｔｅｍｉｃａｌｌｙｄｉｓｃｕｓｓｅｓｔｈｅｆｉｎｉｔｅｅｌｅｍｅｎｔａｎａｌ删ｓｙｓｔｅｍｏｆｔｈｅｗｅｌｄｉｎｇｐｒｏｃｅｓｓｂｙｒｅａｌｉｚｉｎｇｔｈｅ３Ｄｄｙｎａｍｉｃｓｉｍｕｌａｔｉｏｎｏｆｗｅｌｄｉｎｇｔｅｍｐｅｒａｔｕｒｅｆｉｅｌｄａｎｄｓｔｒｅｓｓｆｉｅｌｄ，ｔｈｅｎｕｓｅｓｔｈｅｒｅｓｅａｒｃｈｒｅｓｕｌｔｔｏｓｉｍｕｌａｔｅｔｈｅｗｅｌｄｉｎｇｐｒｏｃｅｓｓｏｆｂｏａｒｄｓｕｒｆａｃｉｎｇｂｙＦＥＭｓｏｆｔＡＮＳＹＳ．Ａｔｔｈｅｔｈｅｏｒｙｒｅｓｕｌｔ．ｓａｍｅｔｉｍｅ．ｔｈｅｃａｌｃｕｌａｔｉｏｎｒｅｓｕｌｔａｃｃｏｒｄｓｗｉｔｈｔｒａｄｉｔｉｏｎａｌａｎａｌｙｓｉｓｒｅｓｕｌｔａｎｄＴｈｅｍａｉｎｃｏｎｔｅｎｔｓｏｆｔｈｅｐａｐｅｒａｒｅａｓｆｏｌｌｏｗｉｎｇ：ｔｈｅｃａｌｃｕｌａｔｉｏｎｉｎｗｅｌｄｉｎｇｐｒｏｃｅｓｓｉｓａｍａｔｅｒｉａｌｎｏｎｌｉｎｅａｒｐｒｏｃｅｄｕｒｅｔｈａｔｔｈｅｍａｔｅｒｉａｌｐｒｏｐｅｒｔｉｅｓｃｈａｎｇｅｔｈｅｆｕｎｃｔｉｏｎｏｆＧａｕｓｓａｓｗｉｔｈｔｈｅｔｅｍｐｅｒａｔｕｒｅ；ｃｈｏｏｓｅｈｅａｔｓｏｕｒｃｅｍｏｄｅｌ．ｕｓｅｔｈｅｆｕｎｃｔｉｏｎｃｏｍｍａｎｄｔｏａｐｐｌｙｌｏａｄｏｆｍｏｖｉｎｇｈｅａｔＳ０１２Ｉｅ－２．ＡｍａｔｈｅｍａｔｉｃｍｏｄｅｌｏｆｔｒａｎｓｉｅｎｔｔｈｅｒｍａｌｐｒｏｃｅｓｓｉｎｗｅｌｄｉｎｇｉｓｅｓｔａｂｌｉｓｈｅｄｔｏｓｉｍｕｌａｔｅｔｈｅｍｏｖｉｎｇｏｆｔｈｅｈｅａｔｓｏＢｒｃｅ．Ｔｈｅｅｆｆｅｃｔｓｏｆｍｅｓｈｓｉｚｅ，ｗｅｌｄｉｎｇｓｐｅｅｄ，ｗｅｌｄｉｎｇｃｕｒｒｅｎｔａｎｄｅｆｆｅｃｔｉｖｅｒａｄｉｕｓｅｌｅｃｔｒｉｃａｒｃｏｎｔｅｍｐｅｒａｔｕｒｅｆｉｅｌｄａ比ｄｉｓｃｕｓｓｅｄ．Ｔｈｅｐｒｏｂｌｅｍｏｆｔｈｅｆｕｓｉｏｎａｎｄｓｏｌｉｄｉｆｉｃａｔｉｏｎｏｆｍａｔｅｒｉａｌｈａｓｂｅｅｎｓｏｌｖｅｄｂｙｔｈｅｍｅｔｈｏｄｏｆｃｈａｎｇｉｎｇｔｈｅｅｌｅｍｅｎｔｍａｔｅｒｉａｌ．Ｔｈｅｐｒｏｂｌｅｍｏｆｔｈｅｃｏｎｖｅｒｇｅｎｃｅｄｉｆｆｉｃｕｌｔｙｏｒｔｈｅｕｎ—ｃｏｎｖｅｒｇｅｎｃｅｄｕｒｉｎｇｔｈｅｃａｌｃｕｌａｔｉｎｇｏｆｔｈｅｔｈｅｒｍａｌｓｌＴｅｓｓｉｓｓｏｌｖｅｄ；ｔｈｒｏｕｇｈｒｅａｌ－ｔｉｍｅｄｙｎａｍｉｃｓｉｍｕｌａｔｉｏｎｏｆｔｈｅｓｔｒｅｓｓｐｒｏｄｕｃｅｄｉｎｗｅｌｄｉｎｇｐｒｏｃｅｓｓ，ｔｈｅｔｈｅｒｍａｌｓｔｒｅｓｓａｎｄｒｅｓｉｄｕａｌＳｌｌ℃ＳＳｉｎｗｅｌｄｉｎｇｃａｎｂｅｐｒｅｄｉｃｔｅｄｂｙｕｓｉｎｇｔｈｅｓｉｍｕｌａｔｉｖｅａｎａｌｙｓｉｓｍｅｔｈｏｄｉｎｔｈｉｓｐａｐｅｒ．Ｉｎｔｈｉｓｐａｐｅｒ，ａｆｅａｓｉｂｌｅｓｌＩｅｓｓｄｙｎ黜ｆｉｅｓｉｍｕｌａｔｉｏｎｍｅｔｈｏｄｏｎ３Ｄｗｅｌｄｉｎｇｔｅｍｐｅｒａｔｕｒｅｆｉｅｌｄ，ｏｎｆｉｅｌｄｈａｄｂｅｅｎｅｓｔａｂｌｉｓｈｅｄ，ｗｈｉｃｈｐｒｏｖｉｄｅｓｔｈｅｏｒｙｆｏｕｎｄａｔｉｏｎａｎｄｉｎｓｔｒｕｃｔｉｏｎｏｐｔｉｍｉｚｉｎｇｔｈｅｗｅｌｄｉｎｇｔｅｃｈｎｏｌｏｇｙａｎｄｐａｒａｍｅｔｅｒｓ．ＫＥＹＷＯＲＤ：Ｗｅｌｄｉｎｇ，ＮｕｍｅｒｉｃａｌＳｉｍｕｌａｔｉｏｎ，Ｆｉｎｉｔｅｅｌｅｍｅｎｔ，Ｔｅｍｐｅｒａｔｕｒｅｆｉｅｌｄ，Ｓｔｒｅｓｓｆｉｅｌｄ．２．独创性说明本人郑重声明：所呈交的论文是我个人在导师指导下进行的研究工作及取得的研究成果。

SimulationofPMOS...

Simulation of PMOSFET Degradation Kinetics with TCAD SentaurusAbstractThis template demonstrates the use of TCAD Sentaurus for the simulation of thetrap formation kinetics of the Si–SiO2 interface and changes in the threshold voltageof a PM OSFET under negative gate bias, a scenario leading to negative biastemperature instability (NBTI). In this model, the activation energy of the Si-H bonddepassivation process depends on the hydrogen concentration, electric field, andhot-carrier current. The model also accounts for passivation of the silicon danglingbonds by the free hydrogen and its diffusion into the oxide region. Variousexperiments in the template address, in particular, the effects of temperature anddiffusion on the resulting I–V curves of the device.Version InformationThis application note has been designed and verified using TCAD SentaurusVersion Z-2007.03.Running it with previous or future versions may possibly require minor adjustments.Synopsys and the Synopsys logo are registered trademarks of Synopsys, Inc. Copyright © 2007 Synopsys, Inc. All rights reserved.IntroductionThe ability to model the reliability of devices and the mechanisms leading to the deterioration of their performance is of paramount importance to foundries and integrated device manufacturers (IDMs). These companies can cut the costs of test-chip manufacturing by identifying degradation-prone designs through simulation.Depassivation of Si-H bonds and trap formation on the Si–SiO2 interface in M OSFET devices are considered to be important mechanisms of device degradation [1]. Resulting from the trap formation, the negative bias temperature instability (NBTI) has become an issue for CMOS circuitry, shifting drive current, and the threshold voltage of the device [2].TCAD Sentaurus can be used to model predictively this phenomenon using the kinetic degradation model implemented in Sentaurus Device. In this model, the activation energy of Si-H bond-breaking is assumed to be H-density dependent. Furthermore, the energy depends parametrically on the device characteristics under the stress: the electric field and hot-carrier current. The depassivated hydrogen is allowed either to passivate partially the silicon dangling bonds or to diffuse into the oxide layer. A set of parameters allows users to calibrate the model to a particular device and stress conditions. An example of such calibration is presented in the literature [3], where the results of TCAD simulation using this model match the experimental data of an NM OSFET under four different stress conditions. The corresponding simulation flow is presented in the Sentaurus template project Simulation of NMOSFET Degradation Kinetics with TCAD Sentaurus.Considering the various modes of stress of the PMOS and NMOS parts in a CMOS device, the NBTI has been found to be a dominant degradation mechanism of a CM OS inverter, affecting mainly the PMOS part [2]. Therefore, the simulation here focuses on a single PMOS transistor.It is assumed that the user is familiar with the Sentaurus tool suite, in particular, Sentaurus Workbench (SWB), Sentaurus Structure Editor, Sentaurus Device, and Inspect. For an introduction and tutorials, refer to the Sentaurus training material.The focus of this project is to provide a setup that can be used as is or adapted to specific needs. The documentation focuses on aspects of the setups. For details about tool uses and specific tool syntax, refer to the respective manuals. General simulation setupThe simulation is organized as an SWB project. The tool flow of the project is discussed here. It consists of Sentaurus Structure Editor, which creates the analytic PM OS structure, Sentaurus Device, which calculates the device characteristics, and the visualization tool Inspect.Sentaurus Structure EditorThe PM OS structure is created with analytic doping profiles, and appropriate mesh refinements are created in this node. Two SWB parameters are introduced here:■Type is set to the value pMOS.■lgate is set to 0.065 μm.After the structure is created, the generated mesh and doping information are stored in the TDR format file, which is then passed to Sentaurus Device.Sentaurus Device: IdVg_initThe name of the first instance of Sentaurus Device is IdVg_init. It performs a low drain bias I d–V gs sweep for the given device.Inspect: PlotIdVg_initThe name of the subsequent instance of Inspect is PlotIdVg_init. It plots the low drain bias I d–V gs characteristics and extracts:■Vtgm_init [V]: Threshold voltage defined as the intersection of the tangent at the maximum transconductance g m with the V gs axis.■Id_init [A/μm]: Maximum value of the I d curve.■Ioff_init [A/μm]: Drain leakage current at a small value of the gate voltage.Sentaurus Device: DegradationThe next instance of Sentaurus Device is called Degradation. This node sets the appropriate bias conditions for the subsequent Si-H bond degradation simulation and calculates the final I–V characteristics.The following parameters control the simulation flow in this node:■Diffusivity [cm2/s]: This parameter defines the diffusion coefficient responsible for the diffusion of the free hydrogen into the oxide layer. Here, it is assigned the values of 10–15 cm2/s and 0 cm2/s.■Temperature [K]: This parameter controls the temperature at which the degradation simulation is performed. For each of the Diffusivity values, it is assigned the values 300 K and 400 K.Inspect: PlotTrapsThe Inspect instance named PlotTraps visualizes the maximum value of the trap concentration at the Si–SiO2 interface calculated in the transient simulation of the previous instance of Sentaurus Device.Inspect: PlotIdVg_finalI d–V gs curves calculated after the degradation simulation are plotted in the final Inspect instance named PlotIdVg_final. Similar to the first Inspect instance, the values of the characteristic threshold voltage and drain current (Vtgm_final, Id_final, and Ioff_final) are extracted.Tool-specific setupsDevice generation using Sentaurus Structure Editor and Sentaurus Mesh Sentaurus Structure Editor is used to define the PM OS devices in a fully parameterized manner. To adjust details of the devices, the user can modify the top section of the Sentaurus Structure Editor input file sde_dvs.cmd. For example, the substrate background doping level as well as the peak concentration of the halo implant are defined by setting the Scheme variables:(define SubDop 5e17); [1/cm3](define HaloDop 1e18); [1/cm3]The junction depth for the halo, the extension, and the source/drain implants are defined by setting the Scheme variables:(define XjHalo 0.07); [um] Halo depth(define XjExt 0.026); [um] Extension depth(define XjSD 0.12); [um] SD Junction depthThe extent of the nitride spacer and the gate oxide thickness are defined by setting the Scheme variables:(define Lsp 0.1); [um] Spacer length(define Tox 20e-4); [um] Gate oxide thickness Several other geometric, doping, and meshing parameters are accessible in a similar manner. The meshing strategy is designed to result in a high-quality mesh without excessive node counts for a large range of geometric parameters. Sentaurus Structure Editor calls a meshing engine to generate the structure files for Sentaurus Device. Sentaurus Mesh is called from within Sentaurus Structure Editor with:(sde:build-mesh "snmesh" "n@node@_half_msh")This command generates a device structure in TDR format, containing doping and grid data. It should be noted that only half of the PMOS structure is created by Sentaurus Structure Editor and meshed with Sentaurus Mesh. It is subsequently reflected about the vertical axis to obtain the full device. The reflection is performed in Sentaurus Structure Editor by a system call to Sentaurus Data Explorer (tdx): (system:command "tdx -mtt -x -ren drain=sourcen@node@_half_msh n@node@_msh")The option -x instructs Sentaurus Data Explorer to reflect the device along an axis defined by . The given half-structure has three contacts: drain, gate, and substrate, which are defined in sde_dvs.cmd. Of these, the gate and substrate contacts touch the axis of reflection and, upon reflection, are extended and thereby preserve their names. However, the drain contact in the reflected half is named drainmirrored by default. This contact is explicitly renamed to source with the tdx command-line option -ren. The device obtained withconcentration is shownDevice simulation using Sentaurus Device Sentaurus Device is used to simulate the drain current as a function of the gate voltage at a low drain bias (I d–V gs) before and after the simulation of Si-H bond degradation. As previously mentioned, the initial (before simulating the degradation) I–V curve is calculated in the first instance of Sentaurus Device. The degradation simulation and subsequent I–V calculation are performed in the second instance of Sentaurus Device. The initial I–V calculation is straightforward; therefore, in the next section only the latter instance is discussed in more detail.x x min=Sentaurus Device: DegradationThe PMOS is biased to a particular stress condition with the following Quasistationary statement, which ramps both the gate and drain voltages at the same time: Quasistationary(InitialStep=1e-3 Increment=1.35MinStep=1e-6 MaxStep=0.2Goal {Name="drain" Voltage=-0.6}Goal {Name="gate" Voltage=-1.2}){Coupled {Poisson hQuantumPotential HolehTemperature}}After the appropriate stress is set up, a transient simulation is performed simulating the kinetics of Si-H bond-breaking: Transient(InitialTime=0 Finaltime = 315e6Increment=2 InitialStep=0.1 MaxStep=1e7){Coupled {Poisson hQuantumPotential HolehTemperature}}Trap concentration along with other variables is stored in the respective Traps_n<number>_des.plt file, where <number> is the Sentaurus Device node in the Sentaurus Workbench project tree.The degradation model is invoked using the keyword Degradation in the Traps section of the material interface–specific physics. The syntax used in the Degradation_des.cmd file is:Physics(MaterialInterface="Silicon/Oxide"){Traps(Conc=1e8 EnergyMid=0 DonorDegradationActEnergy=2 BondConc=1e12DePasCoeff=8e-10 PasTemp=300FieldEnhan=(0 1 1.95e-3 0.33)CurrentEnhan=(0 1 1 1)PowerEnhan=(0 0 -1e-7)DiffusionEnhan=(2e-7@*****************.0e01e1315)}Refer to the Sentaur us Device User Guide for detailed information about the degradation model, its description, and associated keywords.The keyword CurrentPlot is used to store the value of the interface trap concentration (a minimum, maximum, or average value of the concentration, as well as the concentration at the particular node can be stored) at each convergent time step during transient simulations, in the aforementioned plot files:CurrentPlot{eTrappedCharge(Maximum(MaterialInterface = "Silicon/Oxide")) hTrappedCharge(Maximum(MaterialInterface = "Silicon/Oxide")) eInterfaceTrappedCharge(Maximum(MaterialInterface = "Silicon/Oxide")) hInterfaceTrappedCharge(Maximum(MaterialInterface = "Silicon/Oxide")) OneOverDegradationTime(Maximum(MaterialInterface = "Silicon/Oxide")) TotalInterfaceTrapConcentration(Maximum(MaterialInterface = "Silicon/Oxide"))}The resultant trap concentration is shown in Figure2. You can see that the trap concentration and the time interval, in which the steady-state occupation is reached, strongly depend on the diffusion coefficient and temperature. A higher temperature results in a larger trap concentration (characteristic of NBTI) and, for a particular temperature, a calculation accounting for the diffusion of the free hydrogen into the oxide layer also results in a larger trap concentration. The latter effect is observed because the hydrogen that diffused into the oxide cannot passivate backlabeled in legendA detailed analysis of the physical factors and model parameters affecting the general kinetic behavior of the implemented degradation model can be found in the literature [3], where the parameters of the TCAD simulation are calibrated so that the results of the trap accumulation kinetics match the experimental data obtained from an NMOS device.Another Quasistationary statement is invoked after the degradation calculation is completed to bring the device to the normal operating conditions. Finally, the V gs sweep is performed again to calculate I d–V gs characteristics after the degradation.A change in the initial I d–V gs dependency, induced by the traps accumulated in the channel, can be seen in Figure3 on page6.d gs ds mV,before (black dots) and after (solid lines, color code is the same asin Figure2) the degradation simulationExtraction and visualization with InspectIn the Sentaurus Workbench tool flow, the instances of Sentaurus Device are followed by an instance of Inspect. This tool plots the corresponding I–V characteristics and extracts relevant electrical parameters, as discussed in General simulation setup on page3.The extractions are performed using the Inspect library EXTRACT. The library is loaded with the command:load_library EXTRACT(Refer to the Inspect User Guide for a general description of the library.)The following routines of this library are used in this project.ExtractVtgmThis routine extracts the threshold voltage using the maximum transconductance method. The routine is called with:ExtractVtgm <Name> <Curve> <Type>where Name defines the name of the extracted parameter as it appears in the Variable Values view of Sentaurus Workbench, Curve refers to the name of the Inspect I d–V gs curve, and Type can be either "nMOS" or "pMOS". The routine passes the extracted value to Sentaurus Workbench and prints it to the log file. It also returns the value to Inspect. For example, the call:set Vt [ExtractVtgm Vtgm_init IdVg pMOS]results in output such as:DOE: Vtgm_init -0.339Vt (Max gm method): -0.339 VExtractMaxThis routine extracts the maximum drain current. The routine is called with:ExtractMax <Name> <Curve>where Name defines the name of the extracted parameter and Curve refers to the name of the Inspect I d–V gs curve. For example, the call:set Id [ExtractMax Id_final IdVg]results in output such as:DOE: Id_final 3.495e-05Imax: 3.495e-05 A/umExtractIoffThis routine extracts the drain leakage current. The routine is called with:ExtractIoff <Name> <Curve> <Voff>where Name defines the name of the extracted parameter, Curve refers to the name of the Inspect I d–V gs curve (computed for a high drain bias), and Voff defines the gate voltage at which the drain leakage current is extracted, typically, at a small nonzero value to avoid noise.For example, the call:if {$Type == "pMOS"} {set SIGN 1.0}else {set SIGN -1.0}set Ioff [ExtractIoff Ioff_init [expr $SIGN*1e-4]]results in output such as:DOE: Ioff_init 2.305e-10Ioff: 2.305e-10 A/um.References[1] A. Plonka, Time-Dependent Reactivity of Species inCondensed Media, Lecture Notes in Chemistry, vol.40, Berlin: Springer, 1986.[2]V. Reddy et al., “Impact of negative bias temperatureinstability on digital circuit reliability,” Microelectronics Reliability, vol. 45, no. 1, pp. 31–38, 2005.[3]O. Penzin et al., “M OSFET Degradation Kinetics and ItsSimulation,” IEEE T r ansactions on Elect r on Devices, vol.50, no. 6, pp. 1445–1450, 2003.。

仿真流程集成与自动化优化设计PIDO方案

Mass per PET [kg]
1ヶ月あたりの必要原材料[kg]Necessary raw materials per month [kg]
667939.726
343920.5479
1ヶ月あたりのPETコスト[億円]PET cost per month [100 million yen]
0.922157586
确定参数相关性降低复杂性了解您的设计以最少的工作量优化您的产品验证鲁棒性和可靠性为数字孪生创建高保真度的ROM模型
PET瓶制造工艺案例- Background
6
预制加热
旨在优化PET瓶的制造工艺
Objectives・PET bottle optimum thickness・Preform thickness・Preform heater output
12 parameters: number of fins, fin thickness, fan flow rates and positions
20
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对于每个优化运行，都会根据关键模型响应调整安全系数公差对材料、几何和产量的影响有多大？
21
鲁棒性和可靠性仿真结果
汽车雷达可靠性设计案例—Infineon针对三种不同的设计方案进行可靠性分析，得到方案3的可靠性最高；利用MOP完成几千个设计点计算，大大提升计算速度
新一代最佳元模型技术-集成深度学习算法
Integration of Keras & Tensorflow Libraries
Implementation in custom surrogate interface of optiSLang:Automatic configuration of neurons and layersCross validation to estimate Coefficient of PrognosisAvailable as external python environmentNeural networks are treated as one of a library of approximation models

trnsys英文翻译

图2-2：TRNExe中的在线绘图仪
如图2-2所示，在线绘图仪提供了一些先进功能，如显示任意时间点的变量值：缩放某个区域，并在缩放窗口显示被缩放时间段的变量数值。
2.3可视化建筑模拟界面
TRNBuild(以前称为prebid)是用来输入数据到多区域建筑物。设定所有的建筑结构细节，以及分析建筑热性能时所需的每个参数，比如窗户对光的选择性吸收特性，供暖和制冷参数等。
点击图标，可以隐藏或显示对应变量。例如在按下图3-5中红色圆圈，则隐藏/显示Qaux的图标。
3.2.2 模拟分析：缩放和显示数值
您可以放大模拟绘图仪中的一部分，从而观察短时间间隔内的更详细的参数变化。采用拖放功能，从左上交到右下角，选择进行缩放的部分。在放大窗口中，您可以通过点击坐标轴本身调整Y轴变化区间和X轴范围。当你需要观察的时间范围非常小，很难用直接缩放来实现时，这会非常有用。
模拟引擎采用Fortran语言编辑并将源分配(见源代码目录)，汇编成一个Windows动态链接库（DLL），TRNDll。TRNSYS核心读入它的所有模拟信息（包括用到的部件及其连接情况）到TRNSYS输入文件，且命名为deck文件（*.dck）。模拟引擎同样可以读取其它输入文件（如气象数据），并创建输出文件。仿真引擎因包含可执行程序而得名。同时TRNExe具有在线绘图功能。这是个很有用的工具，由此，在模拟过程中，您可以查看几十个输出变量的变化规律。
图2-3：TRNBuild
TRNBuild创建一个建筑物描述文件（*.bui），其中包括建筑模拟时所需的所有资料。需要注意的是，与TRNSYS15不同：运行模拟时，窗户数据库文件是必需的。
2.4TRNEdit和TRNSED应用
TRNEdit是一个专门编辑器，可用于创建或修改TRNSYS输入文件（decks）。一般用户不推荐使用TRNEdit修改deck文件，熟练的用户可以尝试。大多数用户应当使用演示串口生成和修改deck文件。

牵引电机绕组绝缘层导热系数测定及温度场仿真分析研究

带
包1
云母带半叠包5次，亚胺薄膜半叠包
1，
带包 1
胶云母带包3次，玻璃丝带包
1 云带包 3 ，
带包 1
1.2 样
整体绝缘层结构的厚度在0. 5mm -
1.2mm范围内，故本文采用瞬态热进行测
器 TC3000 用型导热仪。测试
绝缘层样
采用导热样进行
仪器标定。样
头
器2
"
时将绝缘层
紧
保温系统中，保
Key words Traction motor ； insulation layer ； theenai conductivity ； temperature field sirnu-
lation
0引言
牵引电机温度场分析的输入参数对最终结果
的影响起到关键作用，材料的导热系数
是电机温升
要的。以电机材料
定子绕组绝缘层导热采用以结果为
基础的
结果，即（1），该导热以
UDF的形式加载算中。电机转速4000转/分
钟，通风风量0.6 m3/s，进风温度40°C。
2.5 算结果
绝缘层导热采用荐值本文结果
的电机各部分温度场分析结果 8、 9
。
结果可以看出，两种绝缘层导热
算温度
分布存在差异。本文采用的绝缘层导热 .
因子
0.2,
因子设置为0.8*10+。
2.2建立三维模型
实电机结构，存在较多对流场、温场
的部件与结构，同时加了网格模型
分难度，增加了不必要的工作量。故本文先对
电机三维模型进行简化处理,
件，重新
调整各部件装配，消
配间隙。最算

基于ANSYS的金属化膜脉冲电容器放电过程热仿真与分析

收稿日期:2020-10-25㊀㊀㊀通信作者:陈红晓作者简介:陈红晓(1979-),男,四川荣县人,高级工程师,硕士,主要从事薄膜电容器设计与应用研究㊂第39卷㊀第12期2020年12月电子元件与材料ELECTRONIC ㊀COMPONENTS ㊀AND ㊀MATERIALSVol .39No .12Dec .2020基于ANSYS 的金属化膜脉冲电容器放电过程热仿真与分析陈红晓1,刘学孔2,孔米秋3,邓小龙1,余㊀清1(1.成都宏明电子股份有限公司,四川成都㊀610100;2.中国电子技术标准化研究院,北京㊀100007;3.四川大学,四川成都㊀610065)㊀㊀摘要:在金属化膜脉冲电容器放电过程中,脉冲电流通过金属化电极层产生焦耳热量,导致电容器内部温度升高,当温度超过一定值时,电容器可能会受损㊂该文将脉冲电流强度与电极电流分布规律相结合,计算出脉冲电流通过金属化电极层不同区域的热生成率;采用ANSYS 软件对一个金属化聚丙烯膜脉冲电容器的放电过程进行了热仿真分析;其中稳态热仿真结果表明,在脉冲电流重复作用下,最高温度点出现在电容器中心位置,且电容器各部位温度随充放电频率提升而升高;瞬态热仿真结果表明,在峰值为5060A 的单次脉冲放电电流作用下,金属化膜上的最高温升约0.5ħ,单次脉冲电流在电极层上形成的温升较低,电容器内部的温升应是脉冲电流重复作用的结果㊂分析结果揭示了金属化膜脉冲电容器的内部发热规律,对提升脉冲电容器可靠性设计具有一定的参考意义㊂关键词:脉冲电流;金属化膜;电容器;热仿真;分析DOI :10.14106/j .cnki .1001-2028.2020.0706中图分类号:TM 911㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀文献标识码:AThermal simulation and analysis of discharge process of metallizedfilm pulse capacitor with ANSYSCHEN Hongxiao 1,LIU Xuekong 2,KONG Miqiu 3,DENG Xiaolong 1,YU Qing 1(1.Chengdu Hongming Electronics Co.,Ltd.,Chengdu 610100,China;2.China Electronics StandardizationInstitute,Beijing 100007,China;3.Sichuan University,Chengdu 610065,China)㊀㊀Abstract :During the discharge process of metallized film pulse capacitor ,the pulse current produces joule heat through the metalized electrode layer ,which increases the internal temperature of the capacitor.When the internal temperature exceeds certaindegree ,the capacitor might be damaged.In this article ,combining the distribution of pulse current and electrode current ,the pulse current heating rate from different metalized layers was calculated.The ANSYS software was used for thermal simulation of a metalized polypropylene pulse capacitor discharging process.The steady -state thermal simulation result indicates that ,under the affection of the pulse current ,the maximum temperature point appears in the center of capacitor and the temperature of capacitor increases with increasing charge and discharge frequency.The transient thermal simulation result indicates that ,under single peak 5060A pulse current ,the maximum temperature of the metalized film rises about 0.5ħ.And single pulse current caused temperature rising is lower.The internal temperature rising of the capacitor is the result of pulse current affection.This result discloses the internal heating regulation of the metalized film pulse capacitor ,and is helpful to improve the reliable design of the pulse capacitor.Key words :pulse current ;metallized film ;capacitor ;thermal simulation ;analysis㊀㊀脉冲电容器是一种储能元件,它在较长的时间间隔内通过电源充电储存能量,当放电电路被触发时,电容器在极短的时间内对负载放电,形成几千甚至上万安培的脉冲电流,实现对特殊装置的激励与触发㊂脉冲放电电流通过电容器时,在电容器金属化电极上产生焦耳热,此热量会经过介质传递导致薄膜介质发热,电容器内部整体温度升高,薄膜介质劣化,击穿场强下降,自愈增多,寿命下28㊀Vol .39No .12Dec .2020降[1]㊂代新等[2]却提出热应力不是导致金属化膜脉冲电容器喷金层与金属化膜电极边缘的接触失效的主要原因,但该文章缺少对脉冲电流通过金属化电极层产生热量的定量分析与计算㊂要准确评估脉冲电流通过电容器产生的热效应,以及热效应对电容器可靠性的影响,就需要进一步开展脉冲电容器放电过程的热分析与计算工作㊂脉冲电容器在一个充放电周期内,要经历缓慢充电㊁电压保持和快速放电三个阶段[3](如图1所示),其中充电阶段T 1和电压保持阶段T 2为几秒至数十秒;而放电阶段T 3为微秒甚至纳秒级的时间内完成,采用传统测试方法,将难以监测到放电阶段金属化膜温度随时间的快速变化情况㊂图1㊀电容器充放电过程Fig .1㊀Charging and discharging process of capacitor利用热分析软件可以实现薄膜电容器的热仿真与分析,范丽娜[4]基于ANSYS 软件完成了一个汽车电容器的热仿真分析实例,但该分析类型为稳态热分析㊂由于脉冲电容器放电阶段时间与充电和电压保持阶段的时间相差几个数量级,因此放电阶段产生的热量会在充电和电压保持阶段传递到封装材料中,并散发到周围环境中去,如果仅对脉冲电容器采用稳态热仿真分析,其分析结果反映的是电容器在多次脉冲电流作用后,电容器内部达到热平衡时各部分组成材料的温度场分布,不能准确反映金属化电极层和介质薄膜在单次脉冲电流作用下的温度随时间快速变化情况㊂瞬态热分析用于计算一个系统随时间变化的温度场及其他热参数[5],因此要全面获得脉冲电容器在脉冲电流作用下内部材料温度随时间变化情况,需要采用稳态与瞬态热分析相结合的分析方案㊂该文利用ANSYS 热分析软件,对一个电压为4000V ,电容量为0.195μF 的金属化聚丙烯膜电容器在脉冲电流作用下的热量产生过程开展稳态与瞬态热仿真分析,分析结果揭示了金属化膜脉冲电容器内部发热规律,对提升金属化膜脉冲电容器设计可靠性具有一定的参考意义㊂1㊀脉冲电容器放电过程分析1.1㊀脉冲放电电路分析图2为脉冲电容器充电放电试验电路图㊂图2㊀充放电试验电路Fig .2㊀Pulse triggered discharge circuit在图2中V DC 为直流稳压电源,输出电压为4000V ;R 为限流电阻,其作用为限制充电电流和防止放电管导通后,电源对地短路,阻值为1M Ω;T 为三端可控气体放电管,当放电管被触发的时候,具有较低的导通电阻;V S 为触发器,输出高电平时,放电管导通;C X 为金属化膜脉冲电容器,实测电容量为0.195μF ;L S 为放电回路寄生电感㊂按照图2搭建了试验电路,采用示波器监测到电容器的放电电流波形,如图3所示㊂图3㊀电容器放电电流波形Fig .3㊀Capacitor discharge current waveform图3为典型的RLC 阻尼振荡波形,为了便于观察,该波形已作了反向处理,对于RLC 阻尼振荡电路有以下关系[6]㊂衰减振荡周期:T D =2π1LC -(R 2L)2(1)衰减系数:α=R 2L =1T ln I P1I P2(2)陈红晓等:基于ANSYS 的金属化膜脉冲电容器放电过程热仿真与分析第39卷㊀第12期29㊀从示波器读数可以得出:衰减振荡第一个峰值电流为5.68kA ,第二个峰值电流为3.76kA ,振荡周期T 为744ns ,电容量实测值为0.195μF ,代入式(1)和式(2)计算得出线路寄生电感:L s =0.070μH ,导通电阻:R =0.078Ω㊂由于限流电阻阻值较大,可忽略限流电阻对放电回路的影响,因此图2试验电路的放电回路模型可简化为图4所示㊂图4㊀电容器放电电路模型Fig .4㊀Capacitor discharge circuit model在图4中,t =0时刻K 由断开转换为闭合,根据初始条件u c (0)=4000V ,i L (0)=0,参照RLC 串联电路的零输入响应建立微分方程[7]㊂LC d 2u c d t2+RCd u c d t+u c =0(3)根据电路条件:R <2LC求解微分方程,得电容器放电电压表达式:u c (t )=U e -αt cos ωd t ()+αωd sin ωd t ()éëêêùûúú(4)求导数得放电电流表达式:i c (t )=C d u cd t =-UCe -αt(-α2ωd-ωd )sin ωd t ()(5)在式(4)㊁(5)中:衰减系数:α=R2L (6)衰减谐振频率:ωd =1LC-α2(7)将式(6)㊁式(7)代入式(5)并化简得脉冲电容器放电电流表达式:i c (t )=-6692.25e -607142.86t sin(8450969.56t )(8)1.2㊀脉冲电容器结构脉冲电容器采用塑料壳封装,镀锡铜线径向引出,环氧树脂灌封的结构,如图5所示㊂1.外壳;2.芯子;3.环氧树脂;4.喷金层;5.引线图5㊀脉冲电容器结构Fig .5㊀Structure of pulse capacitor电容器芯子采用两层厚度为4.3μm ,宽度分别为31.5mm 和29.5mm 的金属化聚丙烯薄膜经无感卷绕而成,其电极总长度21.5m ㊂聚丙烯薄膜表面蒸镀锌㊁铝金属化层形成电极,通过屏带分割形成四内串结构如图6所示㊂1.聚丙烯膜;2.铝金属化电极;3.锌金属化电极图6㊀电容器内串结构(单位:mm )Fig .6㊀Inner series structure of capacitor (Unit :mm )在图6中铝金属化电极层方阻为20Ω/,为了提升电容器端头耐电流脉冲能力,对与喷金层接触的两个边缘部位的金属化电极层作了宽度为3.1mm 的锌加厚处理,锌金属化电极层方阻为2Ω/㊂陈红晓等:基于ANSYS 的金属化膜脉冲电容器放电过程热仿真与分析30㊀Vol .39No .12Dec .20202㊀稳态热分析2.1㊀建立稳态热分析模型由于电容器结构具有对称性,为了避免重复计算,电容器热分析模型仅绘制了1/4电容器结构模型(如图7),在完成数据处理后,再对仿真图形作对称处理,可获得完整的电容器热分析云图㊂图7㊀电容器1/4结构模型Fig .7㊀1/4structure model of capacitor利用ANSYS 软件进行热分析时,对于稳态热分析,需要定义各部分材料的导热系数[5],电容器各组成部件导热系数如表1㊂表1㊀脉冲电容器材料导热系数Tab .1㊀Thermal conductivity of pulse capacitor materials材料名称导热系数[W /(m ㊃K )]电容器芯子0.19喷金层67引出线401环氧树脂0.4外壳0.42.2㊀热载荷计算脉冲电容器在充㊁放电过程中都会有能量损失,损失的能量等于电容器的全部储能[8]㊂在损失的能量中,电容器消耗的能量所占的比例等于电容器ESR 与回路总电阻的比值[1]㊂对于图2所示充放电试验电路,充电回路中串联了1M Ω的限流电阻,满足R >>ESR ,因此充电过程电容器消耗的能量占比是很小的,可忽略不计㊂对于放电回路,因放电管导通电阻较小,电容器消耗的热量占比较大,电容器发热量主要就在放电过程产生,因此电容器充放电过程发热功率近似为:W c =ESR R 放电ˑ12U 2C (9)式中:W c 为电容器发热功率;ESR 为电容器等效串联电阻;R 放电为放电回路电阻;U 为电容器充电电压;C 为电容量㊂电容器芯子的热生成率,由式(10)确定:Q =W c Vˑ1T(10)式中:Q 为电容器芯子热生成率;V 为电容器芯子体积;T 为充放电周期㊂㊀根据脉冲电容器充电电压4000V ,电容量0.195μF ,芯子体积1.25ˑ10-6m 3,ESR 为0.0036Ω,放电回路总电阻0.078Ω,代入式(9)和式(10),获得电容器在不同充放电周期下的热生成率如表2所示㊂表2㊀不同充放电周期下的热生成率Tab .2㊀Heat generation rate under different chargedischarge cycles充放电周期(s )芯子热生成率(W /m 3)1057605115203192001576002.3㊀网格划分有限元网格划分方法主要包括自由网格划分㊁扫掠网格划分㊁映射网格划分㊂网格划分的精度直接影响到有限元计算结果的准确性,一般而言,随着网格密度的增加,计算精度将提高,但计算时间也随之增加㊂因此要在计算精度和计算经济型之间找到合适的平衡点[4]㊂对图6所示模型内部结构的环氧树脂㊁喷金层㊁引线的形状尺寸差异较大,适合采用自由网格划分,网格单元设定为0.5mm ,网格划分效果如图8所示㊂陈红晓等:基于ANSYS 的金属化膜脉冲电容器放电过程热仿真与分析第39卷㊀第12期31㊀图8㊀电容器模型网格划分Fig.8㊀Meshing of capacitor model2.4㊀稳态热分析结果脉冲电容器散热过程主要以对流散热为主,电容器外壳表面对流散热系数取4W/(m2㊃ħ)[9],设定环境温度为25ħ,将不同充放电周期下的热生成率施加于电容器芯子,启动ANSYS计算流程,软件计算完毕之后,会自动地将具有相同温度的区域用相同的颜色表示,形成温度分布云图,通过云图可以直观地观察电容器模型中温度的分布情况如图9所示㊂稳态热分析结果表明,在不同充放电周期下,电容器温度场分布规律基本是一致的,最高温度点均出现在芯子的中心部位㊂当充放电周期为10s 时,电容器中心部位温度为29.84ħ;当充放电周期为1s时,中心部位温度已升高至73.39ħ㊂由此可见随着充放电频率的提升,电容器各部位温度持续升高,因此脉冲电容器使用时应重视充放电频率对电容器发热量的影响,避免电容器因内部温度过高而发生热失效㊂(a)充放电周期10s温度场分布㊀㊀(b)充放电周期5s温度场分布(c)充放电周期3s温度场分布㊀㊀(d)充放电周期1s温度场分布图9㊀温度场分布Fig.9㊀Temperature field3㊀瞬态热分析3.1㊀建立瞬态热分析模型脉冲电容器的放电过程是在微秒级的时间内完成的㊂在如此短的时间内,电流通过电极产生的热量还来不及向外界传递,因此对于单一放电周期内的瞬态热分析,可忽略电容器与周围环境的热交换,仅需考虑电极层的生热过程以及电极层与介质陈红晓等:基于ANSYS的金属化膜脉冲电容器放电过程热仿真与分析32㊀Vol .39No .12Dec .2020薄膜㊁喷金层之间热传递,而灌封料㊁外壳㊁引出线等部件对瞬态热分析影响较小,在建模时均可忽略㊂图6结构中上下两层金属化膜宽度31.5mm 和29.5mm ,金属化膜厚度为4.3μm ,金属化电极层厚度为纳米级(锌电极层厚度约为30nm ,铝电极层厚度约为1.5nm )㊂三者之间相互存在3个数量级以上的差异,如果按照实际尺寸建模是非常困难的,并且后期图形显示效果也不理想㊂为了降低建模难度,改善图形显示效果,在建模时对微小尺寸作以下处理:(1)聚丙烯膜厚度放大103倍;(2)锌电极厚度放大5ˑ104倍;(3)铝电极厚度放大106倍㊂图6结构具有对称性,为了避免重复的计算,沿中心线截取右侧部分作瞬态热分析,金属化膜内串结构经过放大处理后的建模如图10所示㊂V 1㊁V 3㊁V 10-聚丙烯膜;V 9-锌电极;V 11-喷金层;V 2㊁V 4㊁V 5㊁V 6㊁V 7㊁V 8-铝电极图10㊀金属化膜模型Fig .10㊀Model of metallized film利用ANSYS 进行瞬态热分析时,需要定义材料的导热系数㊁比热容和密度[5]㊂由于建模时部分尺寸做了放大处理,为了保持热分析结果与实际值一致,各部分材料属性需要根据尺寸比例变化情况作如下的调整:(1)沿Y 轴方向的导热系数K YY 作放大处理,放大倍数等于材料厚度放大倍数;沿X 和Z 轴方向的材料导热系数K XX ,K ZZ 不变,(2)材料比热容作缩小处理,缩小倍数等于材料厚度放大倍数;(3)材料密度保持不变㊂调整后的材料属性如表3所示㊂表3㊀调整后的材料属性Tab .3㊀Adjusted material properties材料名称导热系数[W /(m ㊃K )]比热容[J/(kg ㊃K )]密度(kg /m 3)聚丙烯膜K XX 0.12K YY 120K ZZ 0.12 1.880.91ˑ103锌电极K XX 116K YY 5.80ˑ106K ZZ 1167.6ˑ10-37.14ˑ103铝电极K XX238K YY 2.38ˑ108K ZZ 2389.02ˑ10-4 2.7ˑ103喷金层K XX67K YY 6.7ˑ104K ZZ670.2287.29ˑ1033.2㊀网格划分模型采用自由单元格划分形式,网格尺寸设定为0.5mm ,得到金属化膜的有限元模型见图11㊂图11㊀金属化膜网格划分Fig .11㊀Meshing of metallized film3.3㊀热载荷计算脉冲电容器放电过程产生的电流是通过金属化电极层传输的,在电流传输过程中产生焦耳热㊂电容器金属化电极上流过的电流沿膜宽方向从喷金端到留边处是线性减小的,在喷金端处电流为最大值,到留边处减小为0[10],通过图10模型中的电极层电流应符合图12的分布规律㊂陈红晓等:基于ANSYS 的金属化膜脉冲电容器放电过程热仿真与分析第39卷㊀第12期33㊀图12㊀电流分布规律Fig .12㊀Regular of current distribution图12中连接内串电容的金属化电极层和边缘电极层不构成有效电容量,但要通过全部放电电流i c (t ),在有效容量部分,电极层电流i 1㊁i 2㊁i 3㊁i 4是i c (t )与X 坐标相关的线性函数,其中:i 1=i c (t )ˑ(-x0.00429+1.315)(11)i 2=i c (t )ˑ(x0.00429-1.944)(12)i 3=i c (t )ˑ(x0.00429-0.315)(13)i 4=i c (t )ˑ(-x0.00429+2.949)(14)根据电流分布函数,图10模型中金属化电极层热生成率表达式为:Q =(i c (x ,t )L)2ˑR /d e(15)式中:i c (x ,t )为电流函数,与X 坐标及时间有关;L 为电极长度,被分析电容器电极长度为21.5m ;R 为电极方阻,锌电极层为2Ω/,铝电极层为20Ω/;d e 为电极厚度,模型厚度0.0015m ㊂根据式(15),图13不同部位电极层热生成率为:V 9热生成率:Q 0=i c (t )21.5éëêêùûúú2ˑ2/0.0015V 7热生成率:Q 1=(i 121.5)2ˑ20/0.0015V 8热生成率:Q 2=(i 221.5)2ˑ20/0.0015V 2热生成率:Q 3=(i 321.5)2ˑ20/0.0015V 5热生成率:Q 4=(i 421.5)2ˑ20/0.0015V 4㊁V 6热生成率:Q 5=i c (t )21.5éëêêùûúú2ˑ20/0.00153.4㊀瞬态热分析结果图3所示的电流波形随时间呈指数规律下降,在完成10个振荡周期后,电流已经趋于0㊂因此将瞬态热分析结束时间设定为7.44μs ,即10个衰减振荡周期;步进值按1个振荡周期的1/100设定,即7.44ˑ10-2μs ,环境温度设定为25ħ㊂启动ANSYS 计算流程,软件完成计算后,获得第1/41,4,10振荡周期时刻的瞬态热分析结果如图13所示㊂从脉冲放电过程不同时刻的金属化膜温度场分布图可以看出,金属化膜最高温度部位出现在连接4个内部串联电容的3块铝金属化电极层上,该部分电极层通过全部脉冲电流,热生成率较高,且位于芯子内部,热传导能力较弱,因此温度最高;在金属化膜与喷金层结合部位,虽然也通过全部脉冲电流,但因边缘部位采用了低方阻的锌金属化电极设计,热生成率较低,并且喷金层导热系数较高,有利于热量导出,因此金属化膜与喷金层接触部位的温升不明显㊂导出ANSYS 分析数据,绘制图13(d )最高温度部位1和喷金层结合部位2的温度随时间变化曲线,如图14所示㊂被分析电容器电极总长度21.5m ,脉冲峰值电流5060A ,折算出峰值线电流密度已达246.82A /m ,对于金属化膜电容器而言,已经属于超高强度电流脉冲,但在单次脉冲电流作用下,金属化膜中心最高温度部位的温升仅0.5ħ左右;在金属化膜与喷金层结合部位的温升不超过0.1ħ,因此单次脉冲电流作用形成的温升是较低的,不会导致金属化膜因温度过高而受损㊂该仿真结果也证实了文献[2]中热应力不是导致金属化膜脉冲电容器喷金层与金属化膜电极边缘接触失效的主要原因㊂陈红晓等:基于ANSYS 的金属化膜脉冲电容器放电过程热仿真与分析34㊀Vol .39No .12Dec .2020(a )0.186μs(b )0.744μs(c )3.72μs1.最高温度部位;2.喷金层结合部位(d )7.44μs图13㊀金属化膜温度场Fig .13㊀Temperature field of metallizedfilm图14㊀热点温度随时间变化Fig .14㊀Temperature vs.time of hot spot4　结论该文对脉冲电容器放电波形进行了分析与计算,确定了脉冲电流数学表达式,将脉冲电流表达式与电极电流分布规律相结合,确定了金属化膜电容器各部位的热生成率;利用热分析软件对一个金属化聚丙烯膜脉冲电容器进行了稳态与瞬态热仿真分析㊂稳态热分析结果表明,在脉冲电流重复作用下,电容器最高温度点出现在电容器中心部位,并且电容器各部位的温升与充放电频率成正比;瞬态热分析结果表明,在单次峰值电流为5060A 的脉冲电流作用下,金属化膜电极层上的最高温升仅0.5ħ左右,金属化膜与喷金层结合部位的温升不超过0.1ħ,单次脉冲电流形成的温升是有限的,不会导致金属化薄膜温度迅速升高,电容器内部的温升是脉冲电流重复作用的结果㊂参考文献:[1]王博文,李化,赖厚川,等.电压反峰对脉冲电容器寿命特性的影响[J ].强激光与离子束,2014,26(4):040517-2.[2]代新,林福昌,李劲,等.金属化聚丙烯膜脉冲电容器端部接触老化研究[J ].中国电机工程学报,2001,21(8):51-54.[3]张丹丹,姚宗干.脉冲电容器放电时边缘电场计算分析[J ].高电压技术,1995,12(4):14-16.[4]范丽娜.基于ANSYS 的电动汽车用直流滤波电容器热分析[J ].电力电容器与无功补偿,2018,39(2):32-37.[5]贾长治,胡仁喜,康士廷.ANSYS 18.0热力学有限元分析从入门到精通[M ].北京:机械工业出版社,2017.[6]王宗篪,范言金.RLC 串联电路暂态过程衰减系数的谐波分析[J ].大学物理,2008,27(12):32-34.[7]胡翔骏.电路分析[M ].北京:高等教育出版社,2001:336-344.[8]洪正平.电容器充电过程系统的能量损失[J ].山东师范大学学报,2009,24(2):152-153.[9]张学学.热工基础[M ],北京:高等教育出版社,2017:234-278.[10]李浩原,尹婷,严飞,等.金属化膜电容器极板发热计算[J ].电力电容器与无功补偿,2015,36(5):37-40.陈红晓等:基于ANSYS 的金属化膜脉冲电容器放电过程热仿真与分析。

桨式搅拌釜不同桨叶角度下搅拌性能的数值模拟

桨式搅拌釜不同桨叶角度下搅拌性能的数值模拟
杨帆1,2*，孙全平2
1淮阴工学院，机械与材料工程学院，江苏淮安 2江苏省先进制造重点实验室，江苏淮安
收稿日期：2021年3月3日；录用日期：2021年4月12日；发布日期：2021年4月19日
摘要
在现有桨式搅拌釜中，针对不同的桨叶角度，运用Fluent软件对搅拌釜内固液混合效果进行数值模拟。通过分析轴截面液相速度矢量图和固含率云图可知，随着桨叶与水平面间角度的增加，底部的固体颗粒沉积越多，减小桨叶与水平面间角度虽然有利于减少底部固体沉积，但同时导致了上部固体颗粒含量较少。考虑整体混合效果，得出桨叶与水平面间角度成30˚时，搅拌釜内固液混合效果最佳。
关键词
桨式搅拌釜，桨叶角度，固液混合，数值模拟
Numerical Simulation of Stirring Performance of a Paddle Agitator with Different Blade Angles
Fan Yang1,2*, Quanping Sun2
1College of Mechanical and Material Engineering, Huaiyin Institute of Technology, Huai’an Jiangsu 2Jiangsu Key Lab of Advanced Manufacturing Technology, Huaiyin Institute of Technology, Huai’an Jiangsu
2. 模型建立及网格划分
2.1. 模型建立
本文的主要研究对象是桨式搅拌釜，如图 1 示，液面高度为 2.4 m，桨叶数量为 2，安装高度 0.8 m，转速 N = 100/rpm，桨叶直径为 0.6 m。仿真采用的桨叶与水平面间角度分别为 15˚、30˚、45˚、60˚、75˚、 90˚，搅拌物料为水和二氧化硅颗粒。其中二氧化硅密度为 2400 kg/m3，颗粒直径为 7.4 μm，体积分数为 30%；水的密度为 1000 kg/m3，粘度为 0.001003 Pa∙s。

建筑给排水中英文对照外文翻译文献_图文03

建筑给排水中英文对照外文翻译文献_图文03 建筑给排水中英文对照外文翻译文献_图文03建筑给排水中英文对照外文翻译文献(文档含英文原文和中文翻译)外文:Sealed building drainage and vent systems—an application of active air pressure transient control andsuppression AbstractThe introduction of sealed building drainage and vent systems is considered a viable proposition for complex buildings due to the use of active pressure transient control and suppression in the form of air admittance valves and positive air pressure attenuators coupled with the interconnection of thenetwork's vertical stacks.This paper presents a simulation based on a four-stack network that illustrates flow mechanisms within the pipework following both appliance discharge generated, and sewer imposed, transients. This simulation identifies the role of the active air pressure control devices in maintaining system pressures at levels that do not deplete trap seals.Further simulation exercises would be necessary to provide proof of concept, and it would be advantageous to parallel these with laboratory, and possibly site, trials for validation purposes. Despite this cautionthe initial results are highly encouraging and are sufficient to confirm the potential to provide definite benefits in terms of enhanced system security as well as increased reliability and reduced installation and material costs.Keywords: Active control; Trap retention; Transient propagationNomenclatureC+-——characteristic equationsc——wave speed, m/sD——branch or stack diameter, mf——friction factor, UK definition via Darcy Δh=4fLu2/2Dgg——acceleration due to gravity, m/s2K——loss coefficientL——pipe length, mp——air pressure, N/m2t——time, su——mean air velocity, m/sx——distance, mγ——ratio specific heatsΔh——head loss, mΔp——pressure difference, N/m2Δt——time step, sΔx——internodal length, mρ——density, kg/m3Article OutlineNomenclature1. Introduction—air pressure transient control and suppression2. Mathematical basis for the simulation of transient propagation in multi-stack building drainage networks3. Role of diversity in system operation4. Simulation of the operation of a multi-stack sealed building drainage and vent system5. Simulation sign conventions6. Water discharge to the network7. Surcharge at base of stack 18. Sewer imposed transients9. Trap seal oscillation and retention10. Conclusion—viability of a sealed building drainage and ventsystem1.Air pressure transients generated within building drainage andvent systems as a natural consequence of system operation may be responsible for trap seal depletion and cross contamination of habitable space [1]. Traditional modes of trap seal protection, based on the Victorian engineer's obsession with odour exclusion [2], [3] and [4], depend predominantly on passive solutions where reliance is placed on cross connections and vertical stacks vented toatmosphere [5] and [6]. This approach, while both proven and traditional, has inherent weaknesses, including the remoteness of the vent terminations [7], leading to delays in the arrival of relievingreflections, and the multiplicity of open roof level stack terminations inherent within complex buildings. The complexity of the vent system required also has significant cost and space implications [8].The development of air admittance valves (AAVs) over the past two decades provides the designer with a means of alleviating negative transients generated as random appliance dischargescontribute to the time dependent water-flow conditions within the system. AAVs represent an active control solution as they respond directly to the local pressure conditions, opening as pressure falls to allow a relief air inflow and hence limit the pressure excursions experienced by the appliance trap seal [9].However, AAVs do not address the problems of positive air pressure transient propagation within building drainage and vent systems as a result of intermittent closure of the free airpath through the network or the arrival of positive transients generated remotely within the sewer system, possibly by some surcharge event downstream—including heavy rainfall incombined sewer applications.The development of variable volume containment attenuators [10] that are designed to absorb airflow driven by positive air pressure transients completes the necessary device provision to allow active air pressure transient control and suppression to be introduced into the design of building drainage and vent systems, for both ‘standard’ buildings and those requiring particularattention to be paid to the security implications of multiple roof level open stack terminations. The positive air pressure attenuator (PAPA) consists of a variable volume bag that expands under theinfluence of a positive transient and therefore allows system airflowsto attenuate gradually, therefore reducing the level of positive transients generated. Together with the use of AAVs the introduction of the PAPA device allowsconsideration of a fully sealed building drainage and vent system. illustrates both AAV and PAPA devices, note that the waterless sheath trap acts as an AAFig. 1. Active air pressure transient suppression devices to control both positive and negative surges. Active air pressure transient suppressionand control therefore allows for localized intervention to protect trap seals from both positive and negative pressure excursions. This has distinct advantages over the traditional passive approach. The time delay inherent in awaiting the return of a relievingreflection from a vent open to atmosphere is removed and the effectof the transient on all the other system traps passed during its propagation is avoided.2.Mathematical basis for the simulation of transient propagation in multi-stack building drainage networks.The propagation of air pressure transients within building drainage and vent systems belongs to a well understood family of unsteady flowconditions defined by the St Venant equations of continuity and momentum, and solvable via a finite difference scheme utilizing the method of characteristics technique. Air pressure transient generation and propagation within the system as a result of air entrainment by thefalling annular water in the system vertical stacks and the reflection and transmission of these transients at the system boundaries, including open terminations, connections to the sewer, appliance trap seals and both AAV and PAPA active control devices, may be simulated with proven accuracy. The simulation [11] provides local air pressure, velocity and wave speed information throughout a network at time and distanceintervals as short as 0.001 s and 300 mm. In addition, the simulation replicates localappliance trap seal oscillations and the operation of active control devices, thereby yielding data on network airflows and identifying system failures and consequences. While the simulation has been extensively validated [10], its use to independently confirm the mechanism of SARS virus spread within the Amoy Gardens outbreak in 2003 has provided further confidence in its predictions [12].Air pressure transient propagation depends upon the rate of changeof the system conditions. Increasing annular downflow generates an enhanced entrained airflow and lowers the system pressure. Retarding the entrained airflow generates positive transients. External events mayalso propagate both positive and negative transients into the network.The annular water flow in the ‘wet’ stack entrains an airflowdue to the condition of ‘no slip’ established between theannular water and air core surfaces and generates the expected pressure variation down a vertical stack. Pressure falls from atmospheric above the stack entry due to friction and the effects of drawing air through the water curtains formed at discharging branch junctions. In the lower wet stack the pressure recovers to above atmospheric due to the traction forces exerted on the airflow prior to falling across the water curtain at the stack base.The application of the method of characteristics to the modelling of unsteady flows was first recognized in the 1960s [13]. The relationships defined by Jack [14] allows the simulation to model the traction force exerted on the entrained air. Extensive experimental data allowed the definition of a ‘pseudo-frictionfactor’ applicable in the wet stack and operable acro ss the water annular flow/entrained air core interface to allow combined discharge flows and their effect on air。

连续移动三维瞬态激光熔池温度场数值模拟

收稿日期：２００３０７一０７；收到修改稿日期：２００３～１１—１０基金项目：中国科学院“知识创新工程”重大项目（ＫＧＣｘｌ—１１）资助课题。作者简介：席明哲（１９６８一），男，河南人，博士，主要从事激光直接成形金属零件的研究。Ｅ＿ｍａｉｌ：ｘｉｍｉｎｇｚｈｅ＠２６３．ｎｅｔ
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半导体器件的高功率微波毁伤阈值数值计算研究(信号与信息处理专业优秀论文)

ＨＰＭ的电压对器件破坏影响的动态过程，及ＰＮ结对ＨＰＭ响应的截止频率参数
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本文研究途径及模拟方法为下一步ＰＮ结器件的二维模拟及试验数据的理论
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关键字：高功率微波一维瞬态过程模拟Ｆ１ｅｘＰＤＥ
电子科技大学硕士论文
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电子科技大学硕士论文
第一章绪论
１．１论文的背景及研究意义
定向能武器是利用沿一定方向发射与传播的高能电磁波射束以光速攻击目标的一种新机理武器，它包括高功率微波武器、高能激光武器和粒子柬武器。定向能武器的攻击目标隐蔽、杀伤力强、既可用于防御、又可用于进攻。因此，它将成为未来信息化战场上对飞机、舰艇、坦克导弹乃至卫星等高价目标的重要武器系统。
签名：立４ｊ矮二—一日期：ｐ悻芦月圹日
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2024版STARCCM[1]

2024/1/27
14
Physical modeling technology
Comprehensive physics models
STARCCM+provides a comprehensive library of physics models, including fluid dynamics, heat transfer, chemical reactions, turnovers, and more, to accurately simulate a wide range of physical phenolmena
Supports parallel computing for high performance simulations
2024/1/27
10
Development history
01
Initial Development
STARCCM was initially developed in the early 2000s as a general purpose CFD software
2024/1/27
5
Reporting scope
• Scope of the report: This report focuses on the capabilities and applications of STARCCM, covering the fundamental principles of CFD, the software's key features and functionalities, as well as case studies demonstrating its use in different industries

真空热处理炉温度场的有限元数值模拟

以ＧＨ４１６９合金零件为例，采用该模型模拟了整个温度场变化过程。试验工艺：以６ｏｃ／ｍｉｎ的加热速度升温，７２０℃保温９０００ｓ，然后炉冷。图６显示ＧＨ４１６９合金零件的有限元网格图。图６中的ｌ为热电偶测温点。图７给出了真空炉热电偶和１号测温热电偶的模拟值与实验值的比较曲线。图７中可以看出，实验结果与模拟结果吻合较好。说明了本文所建立的真空炉传热模型的准确性。采用有限元法能够正确模拟真空热处理炉的非线性温度场，从而为真空热处理炉的优化设计和真空热处理工艺参数的优化选取提供了新的方法和途径。
对炉温均匀性进行了实验测量，模拟结果与实验结果吻合较好。由此提供了一种良好的真空热处理炉虚拟生产手
段，为真空热处理工艺参数优化奠定了理论基础。
关键。词：真空热处理炉；温度场；有限元；数值模拟
中图分类号：ＴＢ７ｌ；０２４１．８２
文献标识码：Ａ
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真空热处理炉温度场的有限元数值模拟
王明伟
王明伟１，张立文１，江国栋１，张利生２，李辰辉２，张凡云２，张尊礼２
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由于真空热处理具有无氧化、无脱碳、表面光洁度好、变形小、综合力学性能优异、节能、无污染和自动化程度高等一系列突出优点，所以当今大量的工件都使用真空热处理炉进行热处理。传统的真空热处理工艺参数的选取和设备设计都采用实验法和经验公式进行计算得出¨。“，它具有成本高、工艺周期长等缺点。利用数值模拟的方法再现生产过程、优化工艺参数具有显著的优越性。近年来上海交通大学潘健生、大连理工大学张立文等人¨。１在热处理过程数值模拟方面都作了大量工作，应用于生产实践并取得显著的经济效益。但在建立真空热处理炉有限元模型，模拟真空热处理过程方面还未见文献报道。

变压器波过程的仿真分析_学士学位论文精品

学士学位论文变压器波过程的仿真分析变压器波过程的仿真分析摘要电力变压器是电力系统中的重要设备之一，必须保证其可靠运行。

要保证电力变压器的可靠运行，就要使其具有良好的绝缘能力，因为电力变压器的故障主要是绝缘被破坏造成的。

当电力变压器受到雷电冲击时，其绕组的绝缘很容易被破坏，因此必须对电力变压器绕组的波过程进行研究。

本文首先介绍了变压器的等值电容、等值电感和电阻参数的计算方法，然后给出了变压器绕组的等值电路和绕组波过程的计算方法。

进而计算了SFP-180000/220三相无励磁调压电力变压器的等值电容、等值电感和电阻，在其等效电路的基础上利用Matlab/Simulink分别建立了中性点接地和中性点绝缘的电路模型。

分别对这两种电路模型进行仿真分析，得到了对应的初始电位分布、振荡电位分布以及最终电位分布等，分析各电位分布的特点，可以为该型号变压器的绝缘结构设计提供参考。

关键词过电压；波过程；电位分布；纵绝缘The simulation analysis on the transient process oftransformerAbstractPower transformer is one of the important equipments in the power grid, we must ensure its reliable operation. To achieve that goal, the insulation property of power transformer must be fine, for its breakdown mainly caused by the insulation damage. When the power transformer suffered from the lightning surges, the windings insulation was damaged easily, so we have to optimize and design on the power transformers windings insulation structure.Firstly, the computational methods of the inductance, capacitance and the resistance parameter were introduced in this paper, then an equivalent circuit of the transformer was established and the computational methods of the windings transient process were given. Furthermore, the inductance, capacitance and the resistance parameters of SFP-180000/220 three-phase no load power transformer were calculated. Based on the equivalent circuit of transformer, the circuit model in the Matlab/Simulink was established and simulated when the neutrals were grounded and isolated respectively. The relevant initial potential distribution, the oscillating potential distribution, and the final potential distribution and so on were gotten by the simulation. Finally, the characteristics of each potential distribution were analyzed, which could provide some references to the insulation structure design of this transformer.Keywords overvoltage；transient process；potential distribution；winding insulation目录摘要 (I)Abstract (II)第1章绪论 (1)1.1 课题背景及意义 (1)1.2 变压器绕组的波过程国内外研究现状 (2)1.3 课题研究内容 (3)第2章变压器的参数计算 (4)2.1 变压器的等值电容的计算 (4)2.1.1 线饼间介质的等值介电常数εde (4)2.1.2 线圈间介质的等值介电常数εwe (6)2.1.3 变压器线圈几何电容的计算 (6)2.1.4 等值纵向电容的计算 (8)2.2 变压器的电感参数的计算 (12)2.3 变压器的电阻参数的计算 (13)2.4 具体变压器的参数计算 (13)2.4.1 电容的计算 (14)2.4.2 电感的计算 (14)2.4.3 电阻的计算 (15)2.5 本章小结 (15)第3章波过程的模拟 (16)3.1 变压器绕组的等值电路与波过程的求解方法 (16)3.2 波过程的仿真分析 (17)3.2.1 电源的选择 (17)3.2.2 中性点接地时绕组的初始电位分布 (17)3.2.3 中性点绝缘时绕组的初始电位分布 (18)3.2.4 中性点接地时绕组的振荡电位分布 (20)3.2.5 中性点绝缘时绕组的振荡电位分布 (21)3.2.6 中性点接地时的最终电位分布 (22)3.2.7 中性点绝缘的最终电位分布 (23)3.3 本章小结 (24)结论 (25)致谢 (26)参考文献 (27)附录 (29)第1章绪论1.1课题背景及意义研究变压器的主要目的就是提高变压器运行时的可靠性并延长它的使用年限，而变压器运行时的可靠性和它的使用年限又主要决定于它的绝缘水平[1, 2]。

用FDTD法求解传输线方程

用FDTD法求解传输线方程高方平;姚缨英;季苏蕾【摘要】We Transmission line circuit model, telegraph equations (a hyperbolic partial differential equations) , is the starting point of analyzing transmission lines transient process. A simple and quick and effective numerical solution in time domain has been deduced by the aid of circuit theory and computational mathematics and program design. The partial differential equation group has been discretized with the theory of FDTD solution, therefore a bran-new differential computation formation has been obtained. Furthermore, boundary conditions of the basic lumped equivalent circuit mode have been found according to constraints between voltage and current at the ends of lines. Finally voltage and current waveforms has been obtained by simulation. Matlab is used for the simulation of the transient of transmission line under various boundary conditions, various coupling conditions. Simulation results from Matlab are compared with waveforms by the EMTP-ATP simulation software, the efficient of the method is proved.%传输线的电路模型—电报方程(一阶双曲型偏微分方程组)是分析传输线暂态过程的出发点.借助电路理论、计算数学、程序设计等知识推导出一种简单、快速、有效的时域数值解法.利用有限时域差分理论对偏微分方程组进行离散,得到一种全新的差分计算格式,并根据电压、电流在始端、终端上的约束关系,运用传输线集中参数的等效模型确定边界条件；最后仿真计算得到响应波形.并对传输线在不同边界条件、传输线耦合等情况下的暂态过程进行MATLAB编程计算得到仿真波形.并将其仿真波形与EMTP-ATP软件仿真得到的波形进行对比,验证了此方法的可行性.【期刊名称】《华北电力大学学报(自然科学版)》【年(卷),期】2012(039)002【总页数】5页(P12-16)【关键词】电路理论;传输线方程;时域有限差分法;传输线暂态过程;数值解【作者】高方平;姚缨英;季苏蕾【作者单位】浙江大学电气工程学院,浙江杭州310027;浙江大学电气工程学院,浙江杭州310027;浙江大学电气工程学院,浙江杭州310027【正文语种】中文【中图分类】TM720 引言在高压远距离交流电力线路、高频信号电信线路中，在同一瞬间沿线的电压、电流都不相同，必须作为分布参数处理。

基于FLUENT的液氮相变传热的数值模拟_张朋

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随着气动发射技术的发展，气动枪械在军事、治安防爆和民用领域得到广泛应用。以液氮作为发射动力源，利用其汽化膨胀推动弹丸运动，具有采用高压气瓶存储压缩气体的气动枪械的特点，另外，相对于高压气瓶，其对储存条件要求低，稳定性和安全性好，易于长时间储存，可满足一些特殊场合的要求。采用数值模拟方法研究液氮汽化对于后续枪械中液氮相过程及其压力变化情况，变容器结构的设计，具有十分积极的参考作用。国内外许多学者曾采用各种两相流模型计算［1 ］液氮相变传热流动过程。如 Ishimoto 等采用二维漂移流模型计算了液氮在通道内的流动沸腾过［2 ］程。Ｒao 等将常（高）温气液两相流数值计算广泛采用的双流体模型引入低温液体领域内，并对双流体模型相关方程进行了修正和补充，模拟了液氦的热质传输过程。李祥东等
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