具有吸附性的平板型轨道分子屏离轴区域真空特性的研究

轨道分子屏真空系统,是利用分子屏轨道飞行速度远大于轨道环境大气的平均热运动速度,使空间环境对分子屏产生理想的抽速,在尾部形成气体分子的稀化区,达到极高真空.对平板型轨道分子屏,现有的文献中,仅仅计算了沿对称轴线的压力分布,然而,由于实际的分子屏试验,试件是具有一定尺寸的三维物体。仅仅获得对称轴线上的真空信息是不够的,需要对偏离对称轴线的空间点,进行分析计算.文章针对具有吸附性的平板型轨道分子屏,对偏离对称轴线的压力分布计算,提出了一套计算方法,对500km 的轨道高度,计算结果表明:当考察点与分子屏表面的距离(=|Z0|)小于1.0m,偏离对称轴线的距离小于1.6m 时,真空度维持在优于10~(-10)Pa 的数量级。建议在这一尺度范围进行材料试验。

STUDY OF EXTREME HIGH VACUUM IN THE OF-AXIS REGION OF AN ADSORPTIVE PLATE WAKE SHIELD FACILITY

The wake shield facitity(WSF) extreme high vacuum system makes use of the property that its orbiting velocity is several times higher than the ambient atmosphere's thermal velocity,leading to a very high pumping by space,hence a rarefaction region up to extreme high vacuum is produced in the wake rigion of WSF.For the plate WSF, calculations of the vacuum characteristic along the symmetry axis have been done only up to now,but it is far from enough for getting the information along the symmetry axis only.Actually,we use a three-dimensioned test article to conduct an experiment,so calculations for the off-axis region are needed In this paper the author proposed a method of calculating the pressure distribution in the off-axis region of adsorptive plate wake shield facility (PWSF)].The calculations showed that,for an orbit height of 500km,when the distance between the observing point and PWSF is less than 1.0m,and the off-axis deviation is suitable for material's processing in space.