光学器件的空间粉尘高速撞击效应研究

文章利用静电加速器模拟研究了微小空间碎片及微流星体(空间粉尘)高速撞击镀膜石英玻璃、光学透镜和反射镜的撞击效应与累积损伤特性。扫描电镜观察结果表明,被撞击试样表面的损伤形式为不连续的点缺陷,可发现撞击坑、机械破裂、局部熔化和粉尘微粒子附着;分光光度计测试结果显示,经粉尘累积撞击后,光学透镜的透射率和反射镜的反射率均发生较小程度的衰减;此外,借助于原位测试技术捕捉到了微小粒子高速撞击过程中产生的等离子体和发光现象。

空间粉尘探测器研究进展

文章在系统地总结空间粉尘(微小空间碎片和微流星体)探测技术的基础上,重点分析了压电型探测器、半导体型探测器、电离型探测器、组合式探测器等的工作原理、技术特点及其应用,同时简要评述了空间粉尘探测技术的发展趋势。

空间粉尘高速撞击对光学玻璃透过率影响的研究

航天器在轨服役期间会遭受到大量的微陨石及空间微小碎片撞击作用。这些微陨石和空间微小碎片可能吸附在航天器光学玻璃表面,也可能与光学玻璃表面碰撞产生陷坑等缺陷。文章采用爆炸式粉尘加速器加速微米级铝粉末撞击K8光学玻璃,在玻璃表面产生大量碰撞陷坑形成砂蚀磨损现象,利用CΦ-46型分光计测量光学玻璃的透过率。结果表明,光学玻璃磨损区域的透过率明显下降。透过率下降程度与陷坑数量成比例。通过对单个陷坑的计算,当陷坑深度大于或等于一个粒子直径时,光线衰减程度达到最大。

空间粉尘对航天器高温热管撞击效应的研究

本文利用爆炸式和电磁式加速器模拟研究空间粉尘粒子对高温热管的碰撞损伤效应.研究表明,微米级粉尘粒子难以击穿航天器高温热管管壁,但对热管表面的热控涂层光学性能变化有较大影响.亚毫米级粉尘粒子取决于速度的不同,高温热管由表面热控涂层光学性能下降一直到被击穿发生载热体的泄漏现象.针对高温热管在高速粉尘粒子撞击下的运行密封性和辐射功率等问题进行了试验研究及理论分析.测量结果表明,高温热管在工作温度T=900 K时,被粉尘粒子击穿的速度由常温下的5.3 km/s降为4.8 km/s.

深空粉尘环境探测技术综述

空间粉尘携带了跨越时间和空间的大量信息,从星系起源到行星系演化,甚至携带了生命起源的基本物质。空间粉尘环境一方面给人类提供了了解深空环境的媒介,另一方面也对人类空间行为产生影响。随着科学载荷技术的发展,粉尘环境探测器能力也逐渐由单纯记录事件向记录粉尘物化特征扩展。文章综述了目前已经开展的空间粉尘环境探测项目,并以高速撞击效应为切入点讨论了以光学、应力及声波、电学测量、原位捕获与返回检测等技术手段为主的空间粉尘探测技术,指出未来随着深空探测项目的开展和探测对象的扩大,空间粉尘环境探测需求会推动具有复合功能、低质量功耗、高精度的探测技术进一步发展。

北京地区平养育成鸡舍粉尘浓度分布的测试分析

鸡舍内粉尘浓度过高,会危害饲养员的健康和家禽的生产力,还会对周围环境造成污染。了解鸡舍内粉尘浓度空间分布情况,有助于进一步分析粉尘释放和传播规律,为开发更有效的除尘方法,提供一定的理论支持。该文首次应用恒流量多点粉尘测量仪在横断面处均匀布点,对北京某鸡场平养育成鸡舍的粉尘浓度进行了监测,就温湿度、风速、鸡群活动状况等影响粉尘浓度的相关因素进行了比较分析。结果表明:在日间,影响粉尘浓度的主要因素为动物活动。舍内风速对粉尘浓度的影响不显著(p＜0．05)。

Modeling flame propagation speed and quenching distance of aluminum dust flame with spatially random distribution of particles

In this research combustion of aluminum dust particles in a quiescent medium with spatially discrete sources distributed in a random way was studied by a numerical approach.A new thermal model was generated to estimate flame propagation speed in a lean/rich reaction medium.Flame speed for different particle diameters and the effects of various oxidizers such as carbon dioxide and oxygen on flame speed were studied.Nitrogen was considered the inert gas.In addition,the quenching distance and the minimum ignition energy(MIE) were studied as a function of dust concentration.Different burning time models for aluminum were employed and their results were compared with each other.The model was based on conduction heat transfer mechanism using the heat point source method.The combustion of single-particle was first studied and the solution was presented.Then the dust combustion was investigated using the superposition principle to include the effects of surrounding particles.It is found that larger particles have higher values of quenching distance in comparison with smaller particles in an assumed dust concentration.With the increase of dust concentration the value of MIE would be decreased for an assumed particle diameter.Considering random discrete heat sources method,the obtained results of random distribution of fuel particles in space provide closer and realistic predictions of the combustion physics of aluminum dust flame as compared with the experimental findings.