流量可调燃气发生器压力闭环模糊控制算法

为了改进流量可调燃气发生器的调节精度,引入燃气发生器压力闭环控制,针对流量可调燃气发生器压力闭环控制特点,在压力闭环中引入了模糊积分控制,此控制算法响应速度快,超调量较小,不同工况及长时间工作下系统仍然有较好的动态特性.     

基于CATIA的Formulas功能实现二次曲线的G2连续

首先简要概述了物面压力分布与物面外形之间的关系,进而介绍了飞机外形设计中经常用到的一类曲线-二次曲线,并推导出二次曲线G2连续的条件和公式,最后介绍了在CATIA中运用Formulas功能实现二次曲线G2连续的方法,并以实例将该方法应用到飞机外形设计中。     

Seasonal variation of surface refractivity over Nigeria

The seasonal variation of surface refractivity over Nigeria was studied using two years in-situ meteorological data from eight locations over Nigeria. The result shows that the surface refractivity generally has higher value during rainy season than dry season at all location studied. The results also show that the value of surface refractivity increases from arid region in the north to the coastal area in south. The results also show that local meteorology plays a very important role in refractivity variation.     

载人飞船回收着陆半实物仿真系统关键技术研究

载人飞船回收着陆半实物仿真系统是通过模拟飞船返回压力环境,将回收程控装置硬件实物接入仿真回路的一个半实物仿真试验平台。文章简要介绍了该半实物仿真系统的结构,重点叙述了该半实物仿真系统中特有的负压高精度快速调节压力模拟、多通路指令信号处理、混合式网络、多阶段动力学仿真框架等关键技术。     

用于压力传感器校准的高低温试验箱设计

基于压力传感器在高低温环境下的校准需求,设计了一种专用高低温试验箱。其控制温度范围可达到-120℃[KG-*4]~[KG-*7]500℃。提出了高低温试验箱的总体方案,介绍了宽温区温度的实现方法以及高温和低温系统不兼容的解决方法和控制流程。试验验证结果显示,高低温试验箱达到了实现宽温区温度的目的,满足设计指标要求。     

以校企合作推进铁路行业就业准入制度

铁路行业就业准入制度目前面临着诸多问题,校企合作是完善铁路行业就业准入制度的有效途径.建立校企合作机制的具体措施为:校企领导、工程技术人员交叉任职;共同组建"双师型"师资队伍;优化教学计划,科学合理设置课程;共同编写铁路专业教材;共同组建职业资格考评委员会.建立校企合作机制,铁路企业与铁路院校共同培养高技能人才,可以从源头上提高铁路行业就业人才的实际水平,全面提高铁路员工整体素质.     

WANDFULH液压比例阀在多功能液压试验台设计中的应用

比较详细的介绍了世界著名的液压元件公司—WANDFULH（瑞士）的液压比例阀在流量和压力控制方面的几种不同应用,并介绍了相应的Amplifier／oontmller card sd1伺服放大控制板的电路连接和软件应用,以及液压实验台的参数、功能要求和调试过程。     

压力传感器过冲量δ的测量及其在动压测量中的应用

阐述了影响压力传感器过冲量6的因数及其测量方法,指出：当输入信号上升时间大于0．02π／ωd时,压力传感器的过冲量是随输入信号上升时间变化的不定量,用激波管端面安装的方法测得的过冲量是压力传感器的最大过冲量;不是所有动态压力测量场合都需要考虑压力传感器过冲量的影响;压力传感器的过冲量应该按照实际工作状态进行标定。     

某型减压器安全阀持续放气故障试验研究

某型飞机氧气系统所用的集成减压器在使用过程中连续多次出现低压安全阀持续放气故障,为了分析故障原因,根据该型减压器结构和工作原理,结合对故障现象和故障树的分析,设计相关试验,提出改进措施,并进行试验验证。结果表明：减压活门的阻尼特性与减压器的输出流量不匹配是导致故障的主要原因。在大流量情况下,减压活门一直处于振动状态,使其产生一定的磨损,致使减压器输出压力缓慢爬升而导致安全阀开启;当安全阀开启时,安全阀排气量远大于额定输出流量,减压器丧失压力调节功能,直至将瓶内气体排空。通过改变减压活门的阻尼特性,排除了该故障。     

Study of thermo-fluidic characteristics for geometric-anisotropy Kagome truss-cored lattice

The aim of this paper is to provide a comprehensive comparison of the thermal insulation and heat transfer performance for Kagome truss-cored lattice along two perpendicular orientations OA and OB. Three test conditions are conducted under forced air convection for the titanium sandwich panel fabricated by 3 D printing technology. The thermo-fluidic characteristics are further explored by numerical simulation to reveal the underlying mechanisms of heat transfer enhancement.The results indicate that the orientation OB exhibits better thermal insulation than orientation OA under the identical temperature loading, while the latter outperforms the former by up to 20% higher overall heat transfer performance. In particular, the endwalls and lattice core in orientation OA achieve 9.7% and 22.5% higher area-averaged Nusselt number respectively than that in orientation OB for a given Reynolds number. The heat transfer superiority of orientation OA comes from the unique topology which induces the large scale spiral primary flows, facilitating the heat exchange between the cooling air and the surfaces of sandwich panel. However, the complex flow mixing leads to a maximum of 20% higher friction factor in orientation OA than that in orientation OB.