某雷达密闭控制柜散热特性的数值模拟研究

为了获得控制柜内外温度场分布,利用专用电子设备热设计软件Flotherm,采用有限容积法对电子设备温度场进行了数值分析,建立了温度场求解方程,分析了电子设备整体热源并建立了网络传热模型,建立了控制柜在多种工作环境条件下的数值仿真计算模型。利用该方法对控制柜进行仿真,获得了控制柜在不同工作环境下全功率工作时的稳态温度场分布,分析了相关因素的影响,为控制柜的进一步设计及相关研究提供了重要依据。     

栅控电子枪的热特性分析

利用ANSYS 有限元软件分析了栅控电子枪的热特性,包括稳态温度场计算和结构热形变,其中稳态温度场计算包括电子枪和栅网的温度分布以及栅网因电子截获而引起的温升。并利用行波管设计软件TWTCAD 分析了热形变前后电子光学系统性能的变化。同时还采用热电偶法得到了实际栅网的表面温度,试验结果与仿真结果基本一致,证明了热分析结果的有效性。     

光纤陀螺光纤环温度瞬态效应的模拟仿真

对光纤陀螺(FOG)中的光纤环建立了三维柱坐标模型,通过ANSYS Workbench软件,结合实际检测到的光纤环温度,采用有限元分析法对光纤环在各种温度条件下的内部温度场分布进行了模拟仿真,得到光纤环中各层、各圈的时间-温度变化曲线;利用光纤环中温度场分布的仿真结果,及温度瞬态效应相关的热致非互易相位变化理论,编写相关算法,计算出光纤环由温度变化带来的温度漂移;将模拟仿真的温度漂移与陀螺实际输出进行对比,验证了所有模拟仿真工作的正确性,从而对绕环工艺起到理论指导的作用。     

激光近净成形CBN磨具温度场仿真分析

为了探究激光近净成形CBN磨具实验时的温度场分布,用Simufac.Welding对其进行三维建模数值模拟。采用高斯面热源和圆柱体热源组合热源,综合考虑对流、热传导、相变潜热及热物性参数的影响,分析了不同工艺参数下温度场的分布规律,另外进行了实际测温,验证了温度场仿真的可靠性,最后根据剖面显微硬度值分析了激光近净成形加工的急热急冷特征。     

光纤陀螺捷联惯导系统热仿真研究

探讨了光纤陀螺热模型的建立方法,并进行了实验验证,在此基础上建立光纤陀螺捷联惯导初步热模型,利用基于液体动力学(CFD)的热分析软件Flotherm对惯导系统进行热仿真分析,通过仿真计算,从而得到惯导系统在室温条件下,通过自然对流散热达到稳定状态的温度云图,然后对系统实现方案进行优化热设计,使温度对光纤陀螺性能的影响尽量减小,并对下一步温补或温控方案提供理论支持与指导。     

侧边抛磨光纤聚合物热光复合波导的稳态温场分析

根据热传导理论,建立了用聚合物热光材料包裹侧边抛磨光纤并在其中埋入电极的热学模型,利用有限元方法对该模型的热场分布进行了数值计算与分析。在器件结构的三维模型中,考查了沿光纤传输的z方向以及光纤截面内的x,y方向,从这三个方向分析和比较了电极单条直放结构与电极螺绕排布结构时热光材料的温度场分布情况。本工作确定了用聚合物热光材料和侧边抛磨光纤来制作新型无源器件时,实现较优温度场分布的合适的电极排布结构方式。     

单道激光熔覆温度场仿真及实验研究

为了研究单道激光熔覆薄板的温度场分布,采用仿真与实验对照的方法,利用ANSYS软件,通过高斯热源模型模拟激光光束能量,再采用非线性边界设定,对单道激光熔覆及冷却过程的温度场进行仿真;使用2kW光纤激光器将铁基(Fe60)粉末熔覆在2mm厚T9A钢板上,并用热成像仪测量多样点温度.结果表明,激光熔覆薄板温度场的仿真符合实...     

多光束大气激光通信中激光光源的温度场分析

针对所设计的多光束大气激光通信(MALC)系统,建立了激光光源温度场分析的仿真模型,运用热分析软件FLUENT对激光器(LD)的温度场进行了数值仿真,得到了温度场的分布曲线。结果表明,当气流速度大于5m／s时,风冷可以保证发射机终端的最高温度小于LD的安全工作最高温度,可作为MALC的有效散热方式。     

基于遗传算法的MCM热布局优化研究

在多芯片组件（Multi-Chip Module，MCM）的热设计中，MCM内裸芯片组装密度大，且裸芯片是主要发热源，各裸芯片之间的位置布局直接影响MCM内温度场分布，进而影响MCM的可靠性。本文基于热叠加模型，选取裸芯片的平均温度作为评价指标，确定出用于MCM热布局优化的适应度函数，基于遗传算法提出一种MCM热布局优化算法，并编制相应优化程序，实现对裸芯片的热布局优化，得出热布局规则用于指导MCM的实际热设计；采用有限元分析软件ANSYS，对MCM布局优化结果进行温度场-应力场偶合分析，以仿真的方法验证MCM热布局优化算法的有效性。     

DC/DC电源模块的有限元热分析

为解决电源模块的热可靠性问题,利用有限元热分析软件ANSYS对其进行热分析,得到整个模块的温度场分布情况;分析了模块中各生热元件的温升及其之间的热耦合情况;根据热分析结果提出热设计方法.最后,对模块各部分进行重新布局,证实了重新布局后的模块就其热可靠性而言更为合理.     

高温环境下油田测井信息光纤传输方案的设计

针对传统测井传输方案的不足,设计了一种高温测井信息光纤传输方案。采用TI公司MSP系列低功耗单片机作为井下测控芯片,高温光模块为信号收发器,耐高温光纤为传输介质。上位机不仅能向下发送命令来控制井下钻机和传感器,也可将该链路回传的测井信息(比如温度、压力、电阻值等)显示出来。实验结果表明,该方案不仅能够长时间在高温工作环境下(110℃)实现测井信息的远距离宽带传输(可达2Mbit/s),而且能够提供灵活的扩展方式,使占用空间更少、重量更轻。     

高斯激光辐照焦平面探测器温度场分析与仿真

为了研究激光辐照焦平面探测器的温度效应,采用ANSYS有限元软件建立高斯脉冲激光辐照锑化铟红外焦平面探测器的3维结构分析模型,并对该探测器3维温度场效应进行了研究。结果表明,激光辐照下,探测器最大温度出现在最上层的锑化铟芯片上,探测器最大温度达到锑化铟芯片熔点温度798K时,将会引起探测器的热熔融损伤,且熔融损伤阈值受到脉宽、光斑半径等激光参量的影响;高斯脉冲激光辐照下,探测器中各层材料的温度场分布呈现出非连续的高温极值区域,其主要原因是位于锑化铟红外焦平面探测器中间层相间分布的铟柱和底充胶具有迥异的热学性质,并且造成探测器温度场云图中锑化铟芯片、底充胶与硅读出电路高温极值区域形成类似于互补的高温分布。这为进一步研究温升效应引起的应力场分布、提高探测器激光防护性能提供了重要的理论分析依据。     

非均匀温度场下红外热成像仪温控系统设计

为降低外界环境温度和内部发热元件形成的非均匀温度场对红外热成像仪的成像性能影响。通过Proe和Ansys ICEPARK建立红外热成像仪的有限元模型,在红外镜头表面进行黑色阳极氧化、喷砂处理增强辐射换热,以及安装风扇增强对流换热保证高温环境时的散热,低温环境时采用热电阻进行温升设计,并仿真分析红外热成像仪在不同温度环境下整机内部温度分布和红外镜头温度分布情况,并利用在高低温箱的红外热成像仪来观察平行光管中的靶标图的成像质量,验证温控设计的高效性。结果表明:所采用温度控制电路板对风扇与热电阻能进行温度控制,当环境温度下降至0℃和升高至30℃时,启动温控系统使红外热成像仪光学系统温度正常,保证红外热成像仪的成像质量。     

远程红外高温测试系统的设计

为了能实时测量高温场的温度分布及图像,提出了基于红外探测技术、光电转换技术的高温测试系统的总体设计方法,完成了硬件的选型与设计及系统处理与控制软件的开发.系统采集到的高温温度场的图像数据经过串行网络信号转换器、光端机的转换,实现了温度场数据的远程传输及处理;图像数据处理计算机控制指令通过光端机对图像采集单元的参数及运行进行控制.本测试系统最后被成功应用于某型试验,远程取得了温度场的瞬时温度分布.实验结果验证了红外高温测试系统的有效性与实用性.     

An infrared scanning technique for the determination of temperature profiles in microcircuits

Circuit reliability and performance, particularly in high-density microcircuits, are affected by temperature. Therefore, a knowledge of the heat transfer paths and temperature distribution are of prime importance in topological design for efficient circuit performance. The method of thermal profiling described uses infrared scanning. The method is direct, rapid, and nondestructive, and the temperature profile is unaffected by the measurement. The effects of heat sinks, heat sources, and unusual geometrical patterns are automatically taken into account. The "heart" of the infrared scanning system is a photosensitive element of single-crystal indium antimonide with a long wave cutoff near 6 microns. The system has successfully determined isothermal patterns from 55°C to >250°C in thin-film tantalum microcircuits having linewidth patterns as small as 2 mils. Isothermal patterns of various geometries are shown to illustrate how the area and shape of resistors affect the thermal pattern and the temperature of the hottest part. Life data correlating the temperatures at the hottest parts with operating stability of thin-film resistive networks is presented. Through the correlation of temperature profiles with storage life tests, the potential exists for greatly reducing the amount of costly life testing of microcircuits for every new bias condition and circuit. Although emphasis is placed on thin-film microcircuits, a thermal profile of a solid silicon microcircuit is presented to indicate usefulness of the infrared scanning technique for temperature profiling of other types of microsystems.     

电子电路的热设计

电子电路热设计是电路设计的重要环节.在阐述电路热设计的一般流程的基础上对电子元件进行了热分析,给出电路热设计的原则,并介绍应用Icepak软件对电路优化设计的方法.     

光纤复合低压电缆温度分布与光单元传输特性研究

研究线缆发热与光单元传输特性变化之间的关系对光纤复合低压电缆(OPLC)设计及应用十分重要。用COMSOL软件模拟仿真光纤复合低压电缆的稳定运行和短路故障状态,得到其相应的电缆温度分布以及光单元传输损耗特性。选取线缆上不同位置处的特征点进行仿真,结果表明：电缆故障时导体绝缘层内升温较明显,外护套温度变化不明显;光纤温度变化很小,其温度在5 s内只有0.2 ℃的上升。由热膨胀引起的位移很小,使得传输损耗在这2种情况下几乎一样,短路故障对光纤的温度影响不大。设计光单元升温实验得到光缆传输损耗的数据,并与仿真数据进行对比分析。实测温度数据滞后于仿真数据5 s,但与仿真数据变化趋势一致,证明了仿真模型的可靠性和可行性。     

Health-monitoring method of note PC for cooling performance degradation and load assessment

Health monitoring technologies, which can evaluate the performance degradation, load history and degree of fatigue, have the potential to improve the effective maintenance, the reliability design method and the availability in the improper use conditions of electronic equipment. In this paper, we propose a method to assess the cooling performance degradation and load history of printed circuit boards in electronic equipment by use of a hierarchical Bayes model based on Computer Aided Engineering (CAE) results of thermal-stress simulation and experiment data from observed measurements. We applied this method to note PC that can monitor the device load factor and revolution number of cooling fan. It is shown that this method can estimate the temperature and deformation distribution of the printed circuit board from monitoring variables through latent variables such as thermal dissipation of the device and thermal boundary condition by use of the hierarchical Bayes model. And it is confirmed that the statistical load assessment concerning thermal cyclic load and the maximum load distribution can be conducted using the estimated temperature and deformation data. Furthermore, we verified that the cooling performance degradation can be assessed, if the temperature difference per unit thermal value between two suitable points on the printed circuit board can be obtained. It is concluded that the proposed method can be effective to assess the thermal load history and cooling performance degradation.     

Electro thermal modeling of the power diode using Pspice

In this paper, an improved electro thermal model of power diode was developed. The main local physical effects were taken into consideration. The suggested model is able to address the electrical and thermal effects. The model was confirmed through a comparison with other models having close characteristics for different circuits (AC-DC converter, turn-on and turn-off) and different temperatures. The diode was implemented in the Pspice circuit simulation platform using Pspice standard components and analog behavior modeling (ABM) blocks. The diode switching performance was investigated under influence of different circuit elements (such as stray inductance, gate resistance and temperature) in order to study and estimate the on-state and switching losses pre-requisite for the design of various converter and inverter topologies. The comparison shows that these models are simple, tunable with the electric circuit software simulator. They are more capable of predicting the main circuit parameters needed for power electronic design. The transient thermal responses were demonstrated for the single pulse and repeat modes. The achieved results show that our model is suitable for full electro thermal simulations of power electronic circuits.     

Thermal analysis of layered electronic circuits with Green's functions

This paper presents a method for thermal simulation of electronic circuits using an analytical solution of the three-dimensional heat equation resulting from an appropriate circuit thermal model. The temperature fields in multilayered structures are computed analytically employing the Green's functions solution method. The entire solution methodology is illustrated in detail on the particular examples of electronic circuits containing multiple heat sources. Compared to the previous papers published by the authors, the method has been extended by including the possibility of simulating imperfect layer contacts. The simulation results are validated with infra-red measurements and results obtained using other methods. Additionally, the discussion of simulation errors caused mainly by different non-linear phenomena is included.