某型无人机液冷装置的实时仿真

以某型无人机的液冷装置为研究对象,使用simulink建立了该装置主要组件的数学模型。利用MATLAB的RTW工具箱以及VxWorks实时操作系统搭建了对此模型的实时仿真系统,并用labview软件建立了友好的人机界面。完成了对模型的测试,仿真结果与设计值的对比表明该模型的精度满足要求,为类似系统模型的建模与仿真及实时控制软件的性能分析提供了参考。     

国产风机盘管空调系统常见问题分析

分析了国产风机盘管使用中常见的问题,指出机组因风量不足、冷量风量匹配不合理以及风机盘管某些设备故障,导致了风机盘管精度低、舒适性差、能耗高等一系列问题。指出应引起空调设计和运行维护人员的注意。     

某医院建筑应用冷热电三联供系统的可行性分析

以上海某医院建筑作为冷热电三联供系统计算与分析的基础,对医院建筑的能耗特性进行了深入探讨,引入热电比、热电比频数和热电比时间数的概念,用以反映该医院建筑的冷、热、电负荷特性,得出医院建筑是冷热电三联供系统较合适用户的结论。     

气膜孔布置形式对发动机中心锥冷却与红外抑制特性的影响

对发动机中心锥的红外抑制技术开展数值研究,在中心锥上采取气膜冷却技术,比较了不同气膜孔布置形式对冷却与红外抑制特征的影响.外涵低温气流通过支板引入中心锥,在锥体前端形成气膜覆盖,使支板与中心锥壁面得到了有效冷却.研究发现,采用气膜冷却后,喷管腔体壁面温度显著降低,中心锥与支板的壁面温度降低13.5％和14.6％.3～5μm波段上红外辐射得到有效抑制,喷管正后方最大降低41％,0～30°范围内红外辐射特征得到显著抑制.     

Reliability enhancement by integrated liquid cooling in power IGBT modules for hybrid and electric vehicles

Insulated Gate Bipolar Transistor (IGBT) modules in power train system of Hybrid and Electric Vehicles (HEV/EV) are working in harsh environment and high reliability and long lifetime are required. In this work, reliability enhancement by integrated liquid cooling structure in HEV/EV IGBT module is investigated. The thermal resistance of junction to heat sink can be reduced more than 50% by direct liquid cooling as eliminating thermal grease layer, so both active and passive temperature swings decrease significantly which will enhance module reliability and lifetime. The lifetime of modules with conventional and integrated liquid cooling structures are estimated under mission of standard driving cycles. We found that lifetime is prolonged obviously by direct cooling pin–fin base plate, and the compact module also makes the application power system simple and reliable.     

Effects of cooling rate on creep behavior of a Sn-3.5Ag alloy

The effect of cooling rate on microstructure and creep behavior of bulk, eutectic Sn-3.5Ag solders was studied. The cooling rate is an important processing variable that significantly affects the microstructure of the solder and therefore determines its mechanical behavior. Controlled cooling rates were obtained by cooling specimens in different media: water, air, and furnace, which resulted in cooling rates of 24°C/s, 0.5°C/s, and 0.08°C/s, respectively. The cooling rate decreased the secondary dendrite arm size and the spacing of the Sn-rich phase, as well as the morphology of Ag₃Sn. The Sn-dendrite arm size and spacing were smaller at fast cooling rates, while slower cooling rates yielded a nearly eutectic microstructure. The morphology of Ag₃Sn also changed from relatively spherical, at faster cooling rates, to needlelike for slower cooling. The effect of cooling rate on creep behavior was studied at 25°C, 60°C, 95°C, and 120°C. Faster cooling rates were found to increase the creep strength of the solder due to the refinement of the solder microstructure. Stress exponents, n, indicated that dislocation climb was the controlling mechanism. Activation energies, for all cooling rates, indicated that the dominant diffusional mechanism corresponded to dislocation pipe diffusion of Sn. Grain boundary sliding (GBS) measurements were conducted, using both scanning electron microscopy (SEM) and atomic force microscopy (AFM). It was observed that GBS had a very small contribution to the total creep strain.     

空调排风热回收与蒸发冷却相结合的应用

简述了空调排风热回收系统与蒸发冷却的基本原理,分析了两种技术相结合在节能和提高空气品质等方面的优点,介绍了几种将热回收和蒸发冷却技术相结合的空调系统,并分析了这些系统的工作原理和优缺点。     

漏电防火报警系统中连续过载电流调度算法的实现

漏电防火报警系统又称剩余电流报警系统,通过探测线路中漏电流的大小来判断火灾的发生的可能性,从而能够提早预防火灾发生,起到与现有消防系统相互补充的重要作用。针对供电系统实际情况,提出基于比例因子的连续过载电流调度算法,考虑到过载长延时,过载短延时以及短路情况的不同,进一步改进控制算法,使得这种控制算法比较适合在该系统中推广。经过现场试验和时间验证,这种对多规格延时的过载电流的调度算法能够反映实际现场情况,较为满意地实现过载电流的控制。     

应力对双极型晶体管参数性能的影响

半导体器件和集成电路中存在着两大类应力,提出了应力及其引起的二次缺陷产生的原因、以及如何减小产生的应力和减少二次缺陷的措施,分析了应力和二次缺陷对双极型晶体管的参数性能的不同影响,以及如何区分产生的这些影响是由何种应力或二次缺陷引起的办法。指出硅片在高温氧化扩散后的科学的慢降温和低温出炉是减小应力和减少二次缺陷的最主要措施,对提高器件参数性能的水平和一致性、提高合格率等起着很重要的作用。     

新型模入通道保护模块在阀冷系统中的应用

针对目前换流阀冷却控制系统中,西门子模拟量输入通道易损坏的现状,介绍了一种新型的模拟量输入通道保护模块。该模块能有效避免高压直流输电工程中换流阀冷却系统模拟量输入通道易损坏的问题,提高了整个换流阀水冷控制系统模拟量采样的可靠性。