Bonding enhancement of cold rolling TA1 P-Ti/AA6061 composite plates via surface oxidation treatment

TA1 P-Ti/AA6061 composite plate was produced by oxidizing the surface of the titanium plate and adopting a cold roll bonding process.The results revealed that the oxide film(Ti6O)prepared on the surface of TA1 pure titanium was easy to crack during the cold roll bonding,thereby promoting the formation of an effective mechanical interlock at the interface,which can effectively reduce the minimum reduction rate of the composite plates produced by cold rolling of titanium and aluminium plates.Moreover,the composite plate subjected to oxidation treatment exhibited high shear strength,particularly at a 43%reduction rate,achieving a commendable value of 117 MPa.Based on oxidation treatment and different reduction rates,the annealed composite plates at temperatures of 400,450,and 500°C displayed favorable resistance to interface delamination,highlighting their remarkable strength-plasticity compatibility as evidenced by a maximum elongation of 31.845%.

Hybrid channeling of Cu-Al cold plates for thermal management devices

Cu-Al cold plates,as a novel type of cold plate that combines the high thermal conductivity of copper with the low production cost of aluminum,are among the best options for enhancing the heat dissipation capacity of battery thermal management systems.Hybrid channeling of Cu-Al cold plates was proposed for thermal management devices with the combination of friction stir welding+channeling.The highest flexural strength of the Cu-Al interfaces reached 127.5 MPa with the optimized parameters.Due to the close-row welds adjacent to the channels,high-efficiency heat dissipation was realized with the fully bonded interfaces.No leakage of coolants occurred under the pressure of 0.85 MPa during the hydrostatic tests,indicating a sound sealing performance of the channels.Compared to the conventional Al cold plates,the heat sink capacity of the Cu-Al cold plates was enhanced by 16.3%.The results indicated that hybrid channeling not only en-hanced the interfacial strength of Cu-Al cold plates but also significantly improved the heat dissipation capacity,offering a new technical pathway for optimizing battery thermal management systems.

Effect of Mechanical Surface Treatment on the Bonding Mechanism and Properties of Cold‑Rolled Cu/Al Clad Plate

In the case of valuable cold-rolled Cu/Al clad plates,billet surface treatment before rolling is a significant process that can affect the bonding efficiency and quality.While the current studies primarily focus on the influence of rolling parameters,insufficient attention has been paid to surface treatment.In this study,the effects of mechanical surface treatment on the bonding mechanism and bonding properties of cold-rolled Cu/Al clad plates were investigated.The results showed that different mechanical surface treatments have significant effects on the surface morphology,roughness,and residual stress.In addition,the effect of surface mechanical treatment on bonding quality was also observed to be critical.When the grinding direction was consistent with the rolling direction(RD),the bonding quality of the Cu/Al clad plates was significantly improved.After surface treatment along the RD for 20 s,the Cu/Al clad plates showed the highest shear strength(78 MPa),approximately four times as high as that of the unpolished samples.Simultaneously,the peel strength of this process was also significantly higher than that achieved via the other processes.Finally,on the basis of the surface morphology,roughness,and residual stress,the effect of surface treatment on the bonding mechanism and bonding properties of Cu/Al clad plates was analyzed.This study proposes a deeper understanding of the bonding behavior and bonding mechanism for cold rolled clad plates processed via mechanical surface treatment.

Design and analysis of a high loss density motor cooling system with water cold plates

Aiming at reducing the difficulty of cooling the interior of high-density motors,this study proposed the placement of a water cold plate cooling structure between the axial laminations of the motor stator.The effect of the cooling water flow,thickness of the plate,and motor loss density on the cooling effect of the water cold plate were studied.To compare the cooling performance of water cold plate and outer spiral water jacket cooling structures,a high-speed permanent magnet motor with a high loss density was used to establish two motor models with the two cooling structures.Consequently,the cooling effects of the two models were analyzed using the finite element method under the same loss density,coolant flow,and main dimensions.The results were as follows.(1)The maximum and average temperatures of the water cold plate structure were reduced by 25.5%and 30.5%,respectively,compared to that of the outer spiral water jacket motor;(2)Compared with the outer spiral water jacket structure,the water cold plate structure can reduce the overall mass and volume of the motor.Considering a 100 kW high-speed permanent magnet motor as an example,a water cold plate cooling system was designed,and the temperature distribution is analyzed,with the result indicating that the cooling structure satisfied the cooling requirements of the high loss density motor.

夏热冬冷地区某三甲医院供暖系统运行性能实测研究

医院建筑具有功能复杂、能耗强度高等特点,是节能减排的重要领域。特别是夏热冬冷地区三甲医院通常采用燃气锅炉系统来满足冬季供暖需求,但易出现能源消耗大、能源利用效率低、碳排放较高等问题。以夏热冬冷地区某三甲医院为例,对其燃气锅炉供暖系统运行能耗、供热量及关键设备实际运行性能开展了实测研究,总结出燃气锅炉频繁启停、板式换热器换热性能不佳、水系统存在大流量小温差,以及末端室内环境冷热不均等问题,存在较大的节能优化空间。

高寒地区中深层地源热泵系统运行表现分析

对青海省共和县中深层地源热泵集中供暖系统实际运行情况展开了研究。通过室内外温度、取水与回灌水温度、供回水温度、能耗和性能系数等数据,综合分析了供热系统实际运行表现。研究结果表明,地热水出水温度存在0.078℃/d的衰减率,为维持地热动态平衡,取水上限流量为80 m 3/h。此外,天气转暖过程中室外平均温度5℃可看作热泵机组启停节点,关闭地源热泵机组仅靠板式换热器换热,能使系统综合性能系数最大升至8.7,系统能耗降幅达42.9%。本文可为地热供暖系统优化运行及能效提升提供参考。

Design and Engineering Application of Direct Mixing Lubrication System for Emulsion Pipeline in Secondary Cold Rolling Mill

With the benefit fierce competition in the steel industry market in recent years,double cold reduction products have been developed towards strength improvement and thickness reduction.The traditional cold-rolling lubrication process with a fixed flow rate and concentration cannot solve the problems,which are uncontrollable plate shape and the excessive consumption of lubricating oil.Moreover,based on the analysis of the traditional direct aplication lubrication system of double cold reduction mill,a set of design scheme suitable for the emulsion pipeline direct mixing lubrication system of double cold reduction mill unit was proposed.The design completed the selection of key components,which included the static mixer and atomization nozzle selection,pump and oil pump design selection,pipeline design selection,flow type selection,pressure gauge selection,electronic control cabinet design selection and other eight aspects.Equipment of the emulsion pipeline direct mixing lubrication system of double cold reduction has been developed.Comparing with characteristics of the traditional direct aplication lubrication system,the emulsion pipeline direct mixing lubrication system was better applied to the production practice of a 1220 double cold reduction mill.The consumption of ton of steel was reduced by 9.6%.The rolling energy consumption and fuel consumption comprehensive costs decreased by 10.7%,and the strip steel section thickness difference was reduced by 19.3%.In addition,the plate shape quality defect rate decreased by 25.6%,otherwise creating a large economic benefit for the unit and promoting the application value.

冷板阻热层对锂电池模组散热均匀性影响

锂电池模组温差过大引发电池间充放电、老化衰减速率不一致,致使其性能变差。为了进一步降低锂电池模组工作温差,提出一种设阻热层的新型冷板,即通过在冷板冷却液入口处与锂电池间增设阻热层增大热阻、抑制锂电池与冷板间热交换改善其散热均匀性。利用新型冷板对锂电池模组3 C放电冷却散热进行建模仿真计算,分析了并行流道、并联蛇形流道以及分叉型流道等3种不同流道冷板增设阻热层对锂电池模组放电散热均匀性影响,以及阻热层材料导热系数、厚度及覆盖面积对锂电池模组冷却散热均匀性影响。结果表明:在3种流道冷板上增设阻热层均能有效降低锂电池模组工作温差。随着阻热层材料导热系数减小,锂电池模组最高温度和温差均先减小后增加。随着阻热层厚度、阻热层覆盖面积增大,锂电池模组工作最高温度和温差均先减小后增大。采用长80 mm、宽80 mm、厚1 mm导热硅胶垫阻热层,分叉型流道冷板冷却锂电池模组3 C放电最高温度和温差降至306.55 K和4.89 K。

动力电池冷板波纹形流道结构的优化

针对动力电池冷却问题,考虑电池模组的布局和散热要求,设计一种具有波纹形流道的冷板,在保证能耗的前提下,控制冷板换热面温度,并具有良好的热均匀性。分析冷板的特征结构,分别讨论波峰波谷高度、流道入射角度及流道宽度对冷板性能的影响。调节流道入射角度可更好地通过流量分配来控制板内压降变化,流道宽度与波峰波谷的设置能改善冷板的热均匀性问题。用最优参数设计的波纹形流道冷板,相比于传统的直流道,换热性能提升8.4%,板内能耗仅提升1.7%。

汽车用SPCC冷轧钢板冲压成形性能比较分析研究

为了评判SPCC冷轧钢板冲压成形性能的优劣性,通过单向拉伸试验、凸耳试验及锥杯试验全面比较了SPCC钢与ZK60板、08Al板、Q235F板、IF板、TRIP600板6种钢板的成形性能。研究结果表明:SPCC的屈服点较低,屈强比σ_(s)/σ_(b)相对较小(约为0.618),断后延伸率δ和硬化指数最高,分别为41.46%与0.265,说明SPCC薄板塑性成形时所需成形力较低,且成形性能也相对较好。SPCC的凸耳率比TRIP600高强钢和IF钢的凸耳率均大,约为6.40%,可通过降温从而减小板材平面各向异性。SPCC的锥杯值与镁合金相近,约为45.3 mm,反映出SPCC具有良好的拉深-胀形综合性能。

不同封装结构相变蓄冷板用于冷藏库数值模拟研究

目的:研究相变蓄冷在冷库错峰用电中的应用,提出更有效的蓄冷板封装结构。方法:针对冻结物冷藏库,设计多种相变蓄冷板封装结构,并建立相应的数值模型。通过数值模拟,在标准温度下(-18℃)测试不同封装结构蓄冷板的凝固蓄冷及融化放冷过程。比较平板蓄冷板和凹凸蓄冷板的异同,并分析不同蓄冷板对库内温度波动的影响。结果:3种特殊版型的蓄冷板中,30~75 mm规格的蓄冷板蓄冷效果最好,在8 h的蓄冷过程中,可比平板型蓄冷板多储存36.23%的冷量。此外,凹凸型封装蓄冷板的放冷能力也要优于平板封装蓄冷板的,能让冷库内温度更加均匀。结论:研究设计的凹凸面封装相变蓄冷板可以在冷库错峰用电中发挥更加有效的作用,能够稳定库内温度并降低能源消耗。

多结构形式小通道液冷板散热性能对比研究

小通道冷板作为一种有效的热控装置,已被广泛应用于高热流密度电子器件的热管理领域。文中以通道特征尺寸为2 mm的串行、并行以及射流冲击/小通道混合液冷板为研究对象,旨在获取这3种结构形式冷板的极限散热能力和流动阻力损失的差异。研究结果表明:在相同冷却工质流量条件下,3种冷板的散热功率由大到小依次为串行通道、射流冲击/小通道混合液冷板、并行通道;串行通道冷板的板内阻力损失明显大于其余两者;在综合考虑压力损失和散热性能的基础上,根据不同热源热流密度条件选择合适的冷板结构,有望满足特定应用的需求。该研究可供小通道液冷板的设计和优化参考。

冷喷涂Cu包覆AlN增强铜基复合涂层的制备与性能研究

目的 通过冷喷涂技术在铜基体上制备了具有高致密高硬度的Cu/AlN涂层,并研究化学镀预处理工艺对冷喷涂Cu/AlN复合涂层微观形貌、力学性能和耐腐蚀性能的影响。方法 采用冷喷涂技术在铜基体表面分别沉积Cu、Cu-AlN(球磨混合)和Cu-Cu@AlN(化学镀包覆)涂层,通过扫描电子显微镜(SEM)观察了涂层截面的微观形貌,通过能谱仪(EDS)对涂层元素组成进行了检测,并计算了涂层中AlN的沉积量。借助维氏硬度计和电化学工作站分别对涂层进行了显微硬度和电化学腐蚀行为测试。结果扫描电镜结果显示,Cu-Cu@AlN和Cu-AlN涂层有着比纯Cu涂层更加致密的微观组织,并且与基体的结合更好,孔隙更少。能谱仪结果显示AlN在涂层中分布均匀,并且Cu-Cu@AlN涂层中AlN的含量明显大于Cu-AlN涂层。Cu-Cu@AlN涂层具有最高的显微硬度(151.8HV),相比基体提升71%。在模拟海洋环境中的电化学测试结果表明,Cu-Cu@AlN涂层的自腐蚀电位最高(-0.1667V),表明其腐蚀倾向最低,自腐蚀电流密度最低(1.18μA/cm^(2)),相比Cu-AlN涂层降低了1个数量级,表明其具有最佳的耐腐蚀性能。电化学阻抗谱(EIS)测试结果表明,Cu-Cu@AlN涂层具有最高的电荷转移电阻(1625?·cm^(2)),证实其具有最佳的耐蚀性,这与动电位极化测试的结果一致。结论 通过化学镀预处理的粉体制备出的Cu-Cu@AlN涂层致密,AlN含量高,该涂层的显微硬度和耐腐蚀性能最好,有望应用在铜及铜合金制备的船舶构件,从而延长其在海洋环境中的服役寿命。

轧制压下率对镍涂层复合板界面微观结构和力学性能的影响

针对镁/铝复合板在轧制过程中接触界面极易生成镁/铝金属间化合物,导致界面结合强度降低的问题,采用“冷喷涂镍中间层+热轧”工艺制备出铝/镁/铝复合板。研究不同压下率对复合板界面微观结构和力学性能的影响。结果表明,“冷喷涂镍中间层+热轧”工艺可有效抑制轧制过程中镁/铝金属间化合物的生成。随着压下率的增加,复合板界面原子扩散层厚度增加,界面结合强度随之增加。当压下率为45%时,界面结合强度达到最高为33.03 MPa。当压下率为35%时,复合板的极限抗拉强度和断裂伸长率达到峰值,分别为328.1 MPa和8.6%,呈现出最优的拉伸性能。当压下率为25%时,由于界面结合强度较低,镁/铝复合板界面在拉伸断裂后出现较严重的分层现象。

双层蛇形通道冷板动力电池热管理数值模拟

针对电动汽车高能量密度动力电池,为改善热管理以确保其安全性,对某型镍钴锰酸锂电池模组提出了一种底部布置的双层蛇形通道冷板;通过数值模拟确定了冷却液的最佳流动方案为方案一和通道的最佳宽度为10 mm,依次分析了冷却液质量流量、电池放电倍率和环境温度对电池模组最高温度、温差和冷却液压力损失的影响.结果表明:随着放电倍率和环境温度的增加,电池模组的最高温度和温差均会增加,增加冷却液的流量可以更好地控制电池的最高温度,但会导致压力损失的增加;放电倍率小于0.7 C时,不需要启动液冷系统.

冷喷涂层对镁/铝复合板界面微观结构和力学性能的影响

针对镁/铝复合板在轧制过程中存在界面极易氧化和析出脆性金属间化合物的问题,采用冷喷涂技术在镁合金基体表面分别制备镍涂层、铝涂层以及镍+铝涂层,按照Al/Mg/Al形式组坯轧制,轧制温度为400℃,压下率为35%。研究了不同冷喷涂层对复合板界面微观结构和力学性能的影响。结果表明冷喷涂3种涂层后,镁合金基体表面粗糙度降低,显微硬度升高。镍涂层复合板表面粗糙度最高,为13.29μm;镍+铝涂层复合板显微硬度最高,为125.23 HV。3种涂层复合板的界面结合强度和抗拉强度均高于无涂层。冷喷镍涂层复合板的综合力学性能最优,结合强度和伸长率最高,分别为19.73 MPa和8.6%,抗拉强度为328.1 MPa,仅次于铝涂层复合板的335.23 MPa。

基于正交试验的热管换热蓄冷板充冷性能研究

车载蓄冷板是充冷式冷藏车的重要组成部分,缩短蓄冷板充冷时间对提高冷链物流的效率具有重要作用。提出了一种热管换热蓄冷板,模拟研究了蓄冷板充冷冻结过程,并通过实验验证了理论模型的可靠性。利用正交试验方法研究了热管管径、管间距、通道内载冷剂流速、雷诺数对蓄冷板充冷性能的影响。研究表明:常规单层厚度约为50 mm蓄冷板状态下,管径为7 mm、管间距为39 mm、通道内载冷剂流速为1.2 m/s、雷诺数为3.89时(最优参数),平均冻结时间和完全冻结时间分别为45 min和78 min;与现有文献报道的结果相对比,最优参数下热管换热蓄冷板的充冷时间大幅缩短。

泵驱动的制冷剂相变冷板冷却系统实验研究

元器件的小型化和性能的提升使电子器件功率不断提高,优越的散热性能对于保证电子器件的可靠性具有重要意义。本文搭建了泵驱动的制冷剂相变冷板冷却实验系统,设计加工了4块不同材质(铜、铝)和流道高度(10、15 mm)的相变冷板,对散热功率为200~1000 W、热流密度为4.4~22.2 W/cm^(2)的集中热源在制冷能力为3~11 kW和不同热源位置时的冷板换热性能、阻力特性及泵功耗进行了研究。结果表明:相变冷板换热性能优越,在应对散热量为1 kW、热流密度为22.2 W/cm^(2)的集中热源时,传热系数最高可达26 kW/(m^(2)·℃),在系统总阻力小于20 kPa、制冷剂泵功耗小于20 W时可以实现模拟热源表面与制冷剂温差小于15℃,可以利用天然冷源进行散热,实现节能;相变冷板的换热特性可由翅片效率计算式和Kandlikar传热关联式进行描述,使用理论公式计算出的冷板温差与实际值偏差小于1℃,可以指导冷板流道设计。

无耳托板螺母组件紧固性能研究

随着航空航天工业的发展,对紧固件的防松性能要求越来越高.打滑失效是新型无耳托板螺母组件一种典型失效形式,当螺母所受扭矩过大时,螺母托板和安装板之间发生打滑,从而失去紧固功能.针对无耳托板螺母组件的打滑失效问题,本文开展了拧脱试验,获得了不同板厚和孔径条件下的极限拧脱力矩.基于Abaqus有限元软件,开展了无耳托板螺母组件的冷挤压和切削工艺仿真,获得了无耳托板螺母组件的残余应力与塑性应变.由于螺母托板与安装板间的摩擦系数难以直接测定,采用试验结合仿真的反推法,建立了摩擦系数的近似线性模型,进而开展了无耳托板螺母组件拧脱的有限元仿真分析,讨论了无耳托板螺母组件中安装板的厚度、孔径以及切削铰孔厚度对拧脱力矩的影响.最后补充了拧脱试验,验证了仿真模型的准确性.结果表明:安装板的板厚、孔径会对冷挤压安装效果有较大影响,较小孔径的安装板在冷挤压安装时会产生更大的塑性变形,因此和螺母托板间有更大的接触应力,安装更为紧密;较大板厚的安装板与螺母托板间的接触应力分布面积更大且更加均匀,两者干涉贴合的效果更好.切削厚度会影响孔边残余应力与塑性应变,进而对拧脱力矩产生影响.利用试验和仿真反推的摩擦系数的近似线性模型所进行仿真预测的安装板尺寸边界,与后续补充试验吻合良好.

电伴热下极地装备踏步板构件的对流换热影响

为解决恶劣极地环境引起的海洋装备防寒问题,工程上通常采用电伴热的方式.采用数值模拟和实验的方法,对电伴热踏步板构件在典型极地环境下热平衡的影响因素进行分析.环境要素为风速和温度,风速为0~40 m/s、温度为-40~0℃.基于数值仿真和实验测试获得电加热踏步板构件在不同风速及温度下的对流换热系数.结果表明,增大风速和降低温度都会增大踏步板的对流换热系数;风速是影响踏步板换热的主要因素,而温度的影响较小.基于实验数据,参考平板构件对流换热的经典理论,建立电加热踏步板构件的对流换热系数预测模型,并采用数值仿真验证该模型的正确性.