整流器件热分析及其风冷散热器的仿真研究

研究整流器优化散热结构设计问题,对电力变换装置小型化和高功率密度要求越来越严格,功率器件散热技术研究和分析变得尤为重要,针对散热器结构散热性差,影响工作的稳定性.为了能够直观和准确地获得散热器温度场的分布特性,根据传热理论建立了整流器件散热的物理模型,采用了热分析方法(有限元法),应用ANSYS软件对风冷散热器温度场进行了数值计算.计算中考虑了整流器件在风冷散热器上的整体布局,着重对两种肋片形状的风冷散热器进行了仿真,结果对比两种风冷散热器的传热效果.给出了风冷散热器优化设计后的实际结构,为散热优化提供了参考.     

基于ANSYS Workbench的T形结构优化设计

针对T形结构传统设计周期长、材料利用率低、设计成本高等问题,使用SolidWorks建立数字模型,将其转换成ANSYS Workbench可读的格式文件,进行拓扑优化设计。对T形结构在载荷作用下进行最优化设计,建立以单元材料密度为设计变量,以结构最小柔顺度为目标函数,以质量减少百分比为约束函数的数学模型。采用ANSYS Workbench的Topology Optimization模块进行拓扑优化设计,对比优化前、后结构的应力和变形,可知运用拓扑优化技术实现T形结构的轻量化设计合理有效。     

车用散热器易损区域的实验分析

为了改善车用散热器易损区域应力分布状态,以21XHP系列散热器为研究对象,通过三维建模、有限元求解等方法对散热器易损区域分析,结果表明,散热器水室两侧加强筋、主片两侧、扁管和主片焊接部位为应力集中区域.并模拟散热器实际工况进行压力交变实验,实验结果表明,仿真所得散热器易损区域分布与实验结果相符,提出对散热器水室两侧加强筋加高加宽、主片加厚、翅片加密等解决方案.最后采用两参数威布尔分布对失效散热器实验数据进行分析,得出散热器失效阶段属于早期耗损故障期,为散热器材料出现高周疲劳所致,需提高材料的屈服强度,减少腐蚀介质等.     

空心轴优化设计

对空心轴传动的优化设计进行了研究。以空心轴的质量作为目标函数,建立了空心轴优化设计的数学模型。根据空心轴设计计算的特点,对设计中的相关参数的规范化计算进行了论述。用Matlab软件、相关语言和复合形法,编写了空心轴传动的优化设计程序。对轴长不小于3m,材料为45钢,所受扭矩为M=1?5×106N·mm的空心轴进行了优化设计。     

基于半导体制冷技术的除湿装置研制

为改善电柜内湿度过高、凝露等问题,研制了一种基于半导体制冷技术的除湿装置。它使湿空气先后流经冷端散热器和热端散热器进行冷凝除湿,并在热端开有补偿进风孔以提高除湿性能。通过实验比较研究了制冷片工作电压、风量和环境温度对除湿能力和除湿效率的影响,并对组件结构和布局、补偿进风口尺寸进行了改进优化,改进后的装置在除湿性能不变的情况下,体积减小了60%。     

SOPC系统的综合优化设计策略

针对SOPC系统优化设计问题,首先介绍了综合优化设计的一般流程和方法,然后从软件优化设置、代码优化设计、片上存储器资源有效分配、NiosII系统优化等方面提出综合优化设计策略。在实验系统中应用该优化策略,SOPC系统最高频率提高了26.62%。     

加固计算机肋片散热器的优化设计

当前许多已投入使用的肋片散热器价格较贵,将其安装在发热量很大的COM Express（COM-E）主板上,在55℃高温工作环境下散热效果不理想。针对商用散热器的不足,本文对COM-E主板肋片散热器进行研究,提出单个肋片热阻的计算方法,并根据COM-E主板的发热量,结合热设计相关计算和仿真,设计优化出一款性能优良的通用型肋片散热器。使用优化后的肋片散热器,加固计算机在高速工作的情况下,顺利通过了高温试验。     

PSpice在电子电路优化设计中的应用

本文提出一种基于PSpice的参数扫描分析、优化分析和蒙特卡罗统计分析相结合的方法对电子电路进行最优化设计,可以有效地提高电路设计的准确性、可靠性和电子产品生产的合格率,并以带通滤波器电路为例,给出了应用该方法实现电路优化设计的仿真过程,实验表明优化设计的结果完全满足设计指标的要求。该方法在优化电路设计中具有很高的实用性。     

基于Java的混合数据结构教学演示系统优化设计

Java是一种可以进行跨平台应用程序撰写的面向对象程序设计语言,Java语言的出现给软件系统设计产业带来了深远影响,因此基于Java对混合数据结构教学演示系统进行优化设计。首先要对混合数据结构教学演示系统的框架进行优化设计,然后对教学演示数据库进行优化设计,也就是对数据库表进行优化设计,将本系统与传统教学演示系统进行实验对比,可以发现本系统性能更加卓越。     

基于混合遗传算法的染色优化模型与仿真

为解决染色工艺优化设计问题,以生产成本最小化为优化目标,构造染色工艺优化设计的数学模型。针对模型非线性约束的特点,采用具有自适应惩罚适值函数和交叉率的混合遗传算法,对模型进行优化计算及仿真。实验结果表明,该方法优化后的生产成本节约了8.8%,证明该优化模型及算法的有效性及实用性,对生产成本的预测以及染色工艺参数的制定具有实际意义。     

Experimental study of heat sink performance using copper foams fabricated by electroforming

In this study, performance of heat sinks using the copper foams as heat-sinking material is investigated experimentally. The copper foam is fabricated by electroforming technique using polymer foam with pre-coated silver film as the precursors. The manufactured copper foams have the porosity, pore density (pore per inch, PPI), permeability and inertial coefficient in the ranges of 0.5–0.8, 10–40, 0.6–2 × 10⁻⁹ m² and 1.5–3, respectively. Besides the copper-foam heat sink, performances of single-channel, plate-fin and pin-fin heat sinks are also investigated and compared with copper-foam heat sinks. The experimentally measured results show that the thermal resistances of copper-foam heat sinks are better than the single-channel, plate-fin and pin-fin heat sinks because of special flow features inside the porous media, enlarged heat-transfer area and enhanced heat transfer coefficient. Detail comparisons between the results of copper-foam heat sinks indicate that the thermal resistance of copper-foam heat sink decreases with the decrease in porosity and increase in pore density. The pressure drop crossing the copper-foam heat sink increases with the increase in pore density and decrease in porosity.     

On the application of Harris hawks optimization (HHO) algorithm to the design of microchannel heat sinks

Engineering with Computers - A novel Harris hawks optimization algorithm is applied to microchannel heat sinks for the minimization of entropy generation. In the formulation of the heat transfer...     

A pin fin microheat sink for cooling macroscale conformal surfacesunder the influence of thrust and frictional forces

Conventional microheat sink design primarily focuses on the use of continuous fin arrays to optimally dissipate thermal energy from electronic components. By contrast, this paper experimentally measures the thermal and structural performance of two micro pin fin heat sinks designed for use in load bearing applications such as mechanical seals and thrust bearings. One pin fin array is of low porosity, which is more optimal for load bearing capacity, and the other is of high porosity, which is more optimal for heat dissipation. By using these two extreme cases, the thermal-structural tradeoff found in load bearing microheat sinks is demonstrated. The heat sinks are constructed of nickel, electrodeposited onto a stainless steel thrust ring using a modified LIGA technique. Under forced air cooling, the thermal performance of each is compared to a simple model based on a combination of macroscale pin fin heat sink results and classical correlations for fins in cross flow. The low porosity design is also tested under the application of a 44.5 N thrust load at 2500 rpm and found to be structurally sound. Experimental temperature profiles demonstrate a substantial benefit of the microheat sink in cooling the load bearing surface     

确保计算机高可靠性的热设计考虑

主要介绍了为确保计算机高可靠性所采取的热设计措施，涉及风扇，散热器，热管，温差致冷，冷致热接触面材料等。，反映了当今这一领域的发展趋势。     

Microchannel heat sink fabrication with roughened bottom walls

Simple bulk wet anisotropic etching procedures that create roughened microstructures along the bottom walls of microchannel heat sinks are presented. The roughened bottom wall is intended to promote flow disturbance and heat transfer enhancement. The basic principle of this study is to utilize the crystal orientation characteristics of 〈110〉 silicon wafers during etching. We first fabricated the microchannel with vertical sidewalls and a bottom wall with a direction of 〈110〉. An experiment is carried out to show that hexagon-like cavities can be produced on the {110} plane using a mask containing parallelograms. The hexagon-like cavity is produced in the microchannel bottom wall also in 〈110〉 direction. In this way, microchannel heat sinks with roughened bottom walls can be produced.     

CPU散热片结构优化设计

本文运用APDL(AnsysParameterDesignLanguage)语言,在ANSYS开发环境中对平板式散热片进行结构优化设计,并给出实例验证本文提出的方法。     

Micromachined jets for liquid impingement cooling of VLSI chips

Two-phase microjet impingement cooling is a potential solution for removing heat from high-power VLSI chips. Arrays of microjets promise to achieve more uniform chip temperatures and very high heat transfer coefficients. This paper presents the design and fabrication of single-jets and multijet arrays with circular orifice diameters ranging from 40 to 76 /spl mu/m, as well as integrated heater and temperature sensor test devices. The performance of the microjet heat sinks is studied using the integrated heater device as well as an industry standard 1 cm/sup 2/ thermal test chip. For single-phase, the silicon temperature distribution data are consistent with a model accounting for silicon conduction and fluid advection using convection coefficients in the range from 0.072 to 4.4 W/cm/sup 2/K. For two-phase, the experimental results show a heat removal of up to 90 W on a 1 cm/sup 2/ heated area using a four-jet array with 76 /spl mu/m diameter orifices at a flowrate of 8 ml/min with a temperature rise of 100/spl deg/C. The data indicate convection coefficients are not significantly different from coefficients for pool boiling, which motivates future work on optimizing flowrates and flow regimes. These microjet heat sinks are intended for eventual integration into a closed-loop electroosmotically pumped cooling system.     

高热流微冷却器的换热性能研究

对以水为换热介质的微通道冷却器对模拟发热电子芯片进行冷却的换热性能进行了实验研究.通过测量流体的流量、进出口温度、发热片表面热流密度,获得了不同几何结构微通道冷却器在不同加热功率、不同Re数条件下的换热特性和冷却效果.结果表明,微通道冷却器可以有效地对表面热流密度高达5.34×105 W/m2的发热电子芯片进行冷却;微通道冷却器的换热性能随Re数的增大而提高,所提高的幅度随加热功率的增大而增大;微通道的几何结构对换热性能有显著影响,平均Nu数随微通道的宽深比增大而增大.     

密封电子设备的热设计分析

随着电子设备热流密度的提升,其散热设计越来越重要。文中根据某工程设备,对其热设计展开分析。首先,依照设备技术指标和环境参数,通过相关计算确定了整机散热方式;然后采用了合理布局机箱内热源、合理布局电路板上高热组件、对高热组件加装散热片和热管、机箱内安装风扇等方法,从而完成了对高热组件进行温度控制的设计目标。