Experimental and CFD analysis of heat sinks with base plate for CPU cooling

Experimental and theoretical investigations of the thermal performance of a variety of heat sinks have been made. The heat sinks investigated were: straight finned, elliptical finned, small pin finned, circular disc finned, elliptical disc finned, frustum finned and double base straight finned. Realistic, manufacturable geometries are considered for minimizing thermal resistance at low velocity. The experimental results of several of the simple geometry heat sinks have been compared to those predicted by a commercially available computational fluid dynamics code fluent. The parameters such as fin geometry, fin pitch and fin height are optimized primarily in this paper and a second task is carried out to optimize base plate thicknesses, base plate materials and modify design of heat sink for improving the thermal performance in the next generation. Although the performance of heat sink is good, the temperature of heat sink at center is high. In this research work, the best heat sink geometry is selected and modified in order to reduce maximum temperature distribution and hot spots of heat sink at center by changing the geometry design and adding one more base. It is observed that flow obstructions in the chassis and the resulting air recirculation affect the heat sink temperature distribution.     

基于ICEPAK仿真的散热器结构热设计研究

文中利用ICEPAK软件对多密度高功率芯片散热器结构进行了热设计研究。研究确立了影响翅片散热器散热性能的关键尺寸设计参数,如基板厚度、翅片高度、翅片厚度和翅片间距等,并得出了各尺寸设计参数对其散热效果的影响趋势,确定了散热器结构的最佳布局方案。此外,研究还建立了最佳布局的散热器结构实物并进行了高低温试验以模拟其高温散热情况。通过实验数据对比发现,仿真计算结果与实际较为吻合,进而验证了ICEPAK软件在电子设备散热设计方面的准确性与可靠性。     

Geometry optimization of a cylindrical fin heat sink using mine blast algorithm

The heat sinks are utilized in electronic devices to eliminate heat from the chip and efficiently transmit it to the environment. Therefore, the optimal geometry sizes of fin heat sinks are the point of concern for manufacturers and designers. For this reason, the importance of optimization techniques particularly metaheuristics is understood. The design variables are width of heat sink, number of fins, fin height, and fin diameter. The various responses that have been considered are electromagnetic emitted radiations, thermal resistance, and mass of the heat sink investigated separately and simultaneously (multi-objective). Mine blast algorithm (MBA), as a recently developed optimizer, is inspired from explosion of mines. The optimum dimensions and values for each response have been obtained by the MBA and have been compared with other optimization methods in the literature. In terms of thermal resistance and mass responses, the MBA has offered better values, while for the emitted radiations, the obtained results obtained by Taguchi-based gray relational analysis (TGRA) was preferred. For manufacturing point of view, the MBA and TGRA both suggested better and efficient design. In addition, the value path analysis has been carried out to compare the trade-off among the considered responses. Finally, parametric sensitivity analyses have been implemented for design parameters, and discussions and comparisons have been carried out for the effects of each decision variable. By considering all responses, width of heat sink and fin height are considered as the most important and effective design parameters, respectively.     

基于ANSYS Icepak的热管模块设计与仿真分析

NVIDIA JETSON TX2高功率系统芯片的散热功率一般在25 W左右,一般的风扇与肋片式散热器组合的散热方式存在体积大、高度高、不方便整合在小型系统中等问题,而热管、风扇、铜鳍片散热器组合的散热方式具有高度低、体积小、传热效率高等优点。文中首先对热管模块进行结构设计;然后对热管模块设计的合理性进行计算验证,并利用ANSYS Icepak对热管模块进行热稳态仿真,发现主要芯片的温度都在要求范围内,表明设计合理;最后将热管模块装入系统进行温度测试。结果表明,主要芯片的计算、仿真与实验的温度基本一致。     

CPU散热器结构设计与热分析

CPU散热器是将CPU核心热量迅速导出的关键,已成为获得新一代电子芯片的主要问题之一。采用数值模拟方法对放射状太阳花CPU散热器进行三维流场及温度场分析,探讨放射状散热器在不同的肋片形状、肋片数N和肋片厚度等各种不同的参数作用下,对于整体散热器散热和流动性能的变化与影响,同时分析了太阳花散热器自然对流和瞬时动态特性。     

水冷盘式制动器散热结构优化

为提高水冷盘式制动器散热性能,基于强化对流传热原理,通过添加扰流柱对制动器散热结构进行优化,设计了4种扰流柱散热结构,运用CFD方法模拟制动盘流固耦合传热过程,采用Fluent软件进行热流固耦合仿真计算,获得制动盘温度特性和换热特性以及流动阻力特性,并使用综合性能评价因子对不同扰流柱散热结构进行评价。结果表明:通过在安装盘水槽内添加扰流柱可以有效地提高水冷盘式制动器的散热效果;在相同的工作条件下,正三角形扰流柱散热结构的盘面温度最低,平均努塞尔数与流动阻力最高,其综合散热性能较圆形、椭圆形以及水滴形扰流柱散热结构分别提高了3.4%,2.4%和4.4%,较无扰流柱散热结构提高了6.7%,正三角形扰流柱散热结构具有更好的综合散热性能。研究结果为水冷盘式制动器散热结构的优化设计提供了参考。     

矩形肋片散热器几何参数对散热的影响分析

为考察矩形肋片散热器几何参数对散热效果的影响规律,文中应用热仿真分析软件Flotherm对矩形肋片散热器在不同结构参数下的模型进行了自然对流散热计算,通过对比分析不同模型的温度和热阻计算结果,探讨了散热器基板参数和肋片参数对其散热性能的影响。分析表明,改变散热器肋片的高度、长度和间距可有效降低散热器的热阻。这些几何参数可以作为散热器热设计变量,以进一步对散热器进行优化设计。     

均热板散热器的传热特性实验研究

为了研究通信设备不同应用场景中散热器传热性能,设计了内嵌均热板散热器、复合芯均热板散热器和金属丝网吸热芯均热板散热器３种不同类型的散热器,针对不同风速、不同放置方向（重力因素）对３种均热板散热器的传热性能进行了实验研究。实验结果表明,在不考虑重力因素的情况下,复合芯均热板散热器具有较好的传热性能,而放置方向（重力因素）对复合芯均热板散热器和单一粉末烧结吸热芯均热板散热器的传热性能影响较大,在散热器设计选型时需要重点考虑均热板散热器的实际应用场景。     

液冷式CPU散热器的传热强化及流阻性能

通过在液冷式CPU散热器蛇形流道内填充不同粒径的不锈钢珠,使液冷式CPU散热器流道形成类似多孔介质的复杂流道以提高其散热性能。通过对改进前后液冷式CPU散热器的试验研究,分析了各因素对液冷式CPU散热器的传热和流阻性能的影响规律。结果表明:在本试验范围内,相同Re和Pr下,改进后散热器的对流换热系数为改进前的1.2~4.8倍,阻力系数f是改进前的1.4~4倍;散热器填充Φ4mm开孔不锈钢珠的强化传热效果最佳,芯片表面温度较填充前降低了33,°对流换热系数增大4.8倍,而流动阻力仅增加了1.4倍。     

铜铝微通道热沉的三维数值结构优化

在恒定泵功0.05 W条件下,对水冷铜基和铝基微通道热沉对流换热进行详细数值模拟和结构优化。通过将数值预测结果与前人已发表的试验结果进行对比,验证所使用的数值模型的正确性。同时讨论在恒定泵功下微通道几何结构对微通道热沉中温度分布的影响。模拟结果显示水冷铜基微通道热沉最优的几何结构参数为通道深为580μm,通道宽为90μm,通道密度为100个/cm;铝基微通道热沉最优的几何结构参数为通道深为620μm,通道宽为80μm,通道密度为100个/cm。     

机载风冷机架高散热性结构设计与验证

文中针对某机型机载设备现场可更换模块(Line Replaceable Module,LRM)结构存在的模块温度过高的问题,提出了一种可提高模块冷却效率和设备集成度的高散热性风冷机架,以此实现机载设备的易散热性和高度集成性.通过设计机架活动风冷隔板结构,改善了冷却风的流动形式,缩短了高热耗LRM模块的传热路径并减小了散...     

基于相变材料和均热板的复合散热技术研究

弹载、机载等平台的雷达干扰设备的工作环境及安装空间要求越来越苛刻,集成度越来越高,同时发射功率需求日益增大,导致设备的热流密度数倍增加,对设备的散热提出了更高的要求。文中采用单一铝实体、铝与相变材料、铝与相变均热板复合3种热沉,通过试验对比其散热效果。结果表明铝与相变均热板复合热沉在综合考虑散热和减重方面具有一定优势。     

Performance analysis of air-cooled microchannel absorber in absorptionbased miniature electronics cooling system

Theoretical analysis and simulation of performance of an air-cooled microchannel absorber is reported in this study. It is shown that the air-cooled microchannel absorber can be integrated into an absorption-based miniature electronics cooling system by which the chip junction temperature can be maintained near room temperature, while removing 100 W of heat load. Water/LiBr pair is used as the working fluid and refrigerant vapor is intended to counter-currently flow against aqueous LiBr solution flow. Parametric study is carried out to determine the effects of several operating parameters, including inlet temperature and mass flow rate of the coolant, and inlet temperature of LiBr solution. To facilitate the air-cooling of microchannel absorber, an offset-strip-fin array is adopted, by which enhanced air-side heat transfer coefficient and large heat transfer area are obtained. The performance of the air-cooled absorber is compared to liquid-cooled absorber.     

Constructal design of finned tubes used in air-cooled heat exchangers

The present study documents the constructal design and optimization of finned tubes used in air-cooled heat exchangers. The considered tubes are equipped with annular fins. The aim is to minimize the overall thermal resistance by morphing the geometry. The geometrical and thermo-physical parameters considered are the number of fins, ratio of fin height to tube diameter, Stanton number, ratio of fin conductivity to air conductivity, ratio of in-tube fluid conductivity to air conductivity and dimensionless pressure drop. Two constraints are applied in the optimization process: fixed overall volume of heat exchanger and fixed volume fraction of fin material. It is found that there exist optimal values for the number and the height of fins. Moreover, the optimal heat transfer has an extremum in a special volume fraction of fin material.     

3D打印三层微通道冷板的综合特性研究

3D打印技术在快速成型和制造复杂结构零件方面具有巨大的优势.文中采用3D打印工艺制备了3种微通道散热器,分别是2种开放型的单层微通道和1种封闭型的三层微通道.对三层微通道散热器(Three-Layered Microchannel Heat Sink,TLMHS)的力学性能进行了压力测试.通过实验和数值仿真研究了50～...     

二维多孔材料散热器的热分析及结构优化

为了改善散热性能,文中对某家电产品中PCB 板上的散热器进行了热分析及结构优化,在翅片散热器热分析的基础上,对2 种二维多孔材料散热器进行了热分析,对比了3 种散热器的散热性能。研究表明:在强迫对流散热条件下,与翅片散热器相比较,二维多孔材料散热器的散热性能更好;六边形多孔材料散热器比矩形多孔材料散热器的散热性能要好,同时更有利于实现结构的轻量化要求,降低材料成本,提高产品利润。     

型材散热器的优化设计

本文针对散热器在强迫风冷条件下的散热性能优化问题进行了分析研究.对于所采用的优化方案的热分析模型作了描述.分析了绕流对散热器性能的影响,并根据一种较为简便的数学模型,用迭代的方法确定出肋片上的实际流速.最后给出了采用这些模型计算出的在不同工作环境下型材散热器的优化尺寸.     

基于6SigmaET 的固态功放模块的热设计

文中针对一种4通道Ku频段高功率功放模块进行了结构设计.通过理论分析确定了散热器的结构模型,重点提出了以均热板与散热器相结合的散热方式来提高功放模块内的温度均匀性和散热效率的方法,同时应用专业仿真软件6SigmaET进行了热仿真验证.结果表明,均热板的采用有效降低了功放芯片的温度,热设计过程合理,可为固态功放模块的散热设计提供参考.     

弹载电子设备相变热沉装置散热性能研究

文中介绍了一种用于弹载电子设备的相变热沉装置的设计方法及试验研究。通过实验对比了电子模块在采用相变热沉装置、铝块和无热沉3种情况下的工作温度曲线,同时对比分析了相变热沉装置在不同热流密度下的工作特性。结果表明,当热源热流密度较小时,相变热沉装置具有明显的减缓热源升温的作用,对比铝块热沉具有明显的散热功效。而随着热流密度的增加,其散热优势逐渐减弱。同时,填料相变温度点的选取和导热增强体的设计,对相变热沉装置的散热性能有很大的影响。     

基于蒙皮换热器的无人机电子设备冷却方案分析

针对无人机应用中日益突出的电子设备发热问题,提出了一种基于蒙皮换热器的无人机电子设备冷却方案。根据设计需求确定了各主要部件的温度要求及换热器效率要求,并对系统进行了试验验证。文中提出的电子设备冷却方案属液体冷却方式,电子设备的发热量可以通过蒙皮换热器传递给舱外冲压空气热沉。通过合理的等效换热测量方法设计的地面性能试验考查了系统运行时各部分温度、换热器的换热量及系统能效比。试验结果表明,该方案有效可行,能够满足较大发热功率的无人机电子设备的冷却需求,具有广泛的应用价值。