低温推进剂单管输送系统的循环预冷实验研究

采用了外加循环支管方式抑制火箭发动机中低温推进剂输送管路中产生的间歇泉现象,对外加支管的低温推进剂单管输送循环预冷系统进行了数值模拟及实验研究。研究了在外加循环支管的管路结构下,增压对循环预冷过程的影响。实验结果表明:单管输送系统中采用外加循环支管的方式可以使整个管路形成循环,这种方法可以有效抑制低温推进剂输送管路中间歇泉现象的产生。     

超声波作用下常温磷化工艺的研究

介绍了一种不含任何有毒、污染环境的促进剂的碳钢表面超声波常温磷化工艺.探讨了超声波、及在超声波作用下磷化工艺参数,如温度、时间和pH值对所得磷化膜外观、膜重和耐蚀性的影响.结果表明:在超声波作用下,磷化液不加任何促进剂也能在碳钢表面实现常温磷化,而且所得磷化膜层均匀、致密,呈灰色;磷化膜层耐硫酸铜点滴时间可达到50～120 s,在3%NaCl溶液中产生锈蚀点的时间为4 h;磷化膜层与漆膜结合力好.     

Study on JAXA elements for international lunar vicinity mission

JAXA has commenced technical research for contributing as a part of international partnership for the space exploration in Lunar vicinity. One of the candidates is the cargo transport mission with the combination of Cryogenic Propulsion Stage(s) (CPS) and a transfer vehicle derived from Japanese un-manned vehicle used for ISS. The CPS needs advanced technologies to keep the propellant for long mission duration and they will be useful in further missions beyond moon. This paper reports the profile of the mission, vehicle configurations, and the transport capabilities.     

低温推进剂输送与预冷系统间歇泉不稳定性数值模拟研究

针对低温推进剂（液氧）输送与预冷系统间歇泉不稳定性进行了模拟与数值试验研究。分析与验证了连接液氧贮箱的底端封闭垂直管路的典型间歇泉不稳定过程,对经验Murphy曲线进行了检验。针对自然循环型的低温推进剂输送与预冷系统不稳定性及典型间歇泉的发生,进行了稳定域的计算与影响参数分析,研究了过冷度、输送管漏热、发动机进出口阻力、回路高度,以及回流管漏热（保温状况）对各域边界的影响。     

Thermal conductivity studies of a polyurea cross-linked silica aerogel-RTV 655 compound for cryogenic propellant tank applications in space

Silica-based aerogel is an ideal thermal insulator with a makeup of up to 99% air associated with the highly porous nature of this material. Polyurea cross-linked silica aerogel (PCSA) has superior mechanical properties compared to the native aerogels yet retains the highly porous open pore network and functions as an ideal thermal insulator with added load-bearing capability necessary for some applications. Room temperature vulcanizing rubber-RTV 655—is a space qualified elastomeric thermal insulator and encapsulant with high radiation and temperature tolerance as well as chemical resistance. Storage and transport of cryogenic propellant liquids is an integral part of the success of future space exploratory missions and is an area under constant development. Limitations and shortcomings of current cryogenic tank materials and insulation techniques such as non-uniform insulation layers, self-pressurization, weight and durability issues of the materials used, has motivated the quest for alternative materials. Both RTV 655 and PCSA are promising space qualified materials with unique and tunable microscopic and macroscopic properties making them attractive candidates for this study. In this work, the effect of PCSA geometry and volume concentration on the thermal behavior of RTV 655—PCSA compound material has been investigated at room temperature and at a cryogenic temperature. Macroscopic and microscopic PCSA material was encapsulated at increasing concentrations in an RTV 655 elastomeric matrix. The effect of pulverization on the nanopores of PCSA as a method for creating large quantities of homogeneous PCSA microparticles has also been investigated and is reported. The PCSA volume concentrations ranged between 22% and 75% for both geometries. Thermal conductivity measurements were performed based on the steady state transient plane source method.     

A short history of the European Transonic Wind Tunnel ETW

This paper is written as a contribution to the celebration of 50 years of Progress in Aerospace Sciences and of the centenary of the birth of its founder, Dietrich Küchemann. It reviews the evolution of the European Transonic Wind Tunnel, ETW, from early conceptual studies to its entry into service and its current capabilities and achievements. It traces the development, from the earliest days, of experimental aerodynamics and of the basic aerodynamic understanding that gave rise to the main periods of wind tunnel building before and after World War II. By about 1960, this activity appeared to have come to a natural halt. The paper gives an account of the role of Küchemann in arguing the need in 1968 for a further step in wind tunnel capability, to provide transonic testing at high Reynolds numbers. It describes his leading role in gaining acceptance of the concept, formulating the specification and promoting studies of alternative, radical design options for the co-operative European project that became ETW. The progress of ETW through design, construction, commissioning and into full operation is recorded. The paper discusses the many technical innovations that have been introduced in order to meet customer requirements in the challenging field of aerodynamic testing in a cryogenic environment and, finally, looks to the future and the further technical challenges that it holds.     

空化对流体管路瞬态特性影响分析

空化（或称气穴）是流体系统中常见的现象，它显著地影响着流体管路的瞬态特性。考虑气体在液体工作介质中溶解和析出以及液体介质自身气化，建立相应的流体属性模型，计算不同压力下流体的等效密度及体积模量；同时以一维管道瞬变流理论为基础，考虑流体系统中的空化及气泡溃灭，采用有限差分法计算流体管路锤击过程中的压力脉动。求得的结果与真实物理现象较为接近，能够为流体系统的设计提供依据和参考。     

深空探测用低温推进剂贮箱热力排气系统研究

Cryogenic propellant usually experiences long term on orbit storage. The pressure increase in cryogenic storage tank is faced by most of space missions. The thermodynamic vent system (TVS) is treated as the promising method to control the increase of the tank pressure by scholars both at home and abroad. Based on the investigation conducted by different research agencies, literature review and management are conducted to reflect the recent research statue on TVS. The development profile of the experimental research on the pressure control performance of TVS is specially summarized. The condition setting and performance difference of TVS conducted by different agencies are compared and analyzed. The key technique and related conclusion are refined during the operation of TVS. Finally, based on the requirement of the large scale using of cryogenic propellant in deep space exploration in China, the development plan is proposed on the aspect of TVS pressure control on cryogenic storage tanks.     

诱导轮出口参数对高速离心泵性能的影响

某型号液体火箭发动机用高速诱导轮离心泵存在抗汽蚀性能偏低的问题,而液体火箭发动机对泵的抗汽蚀性能有特别严格的要求,其直接影响发动机的性能和可靠性。为获得更高的效率,按照常规泵设计经验选取较大的诱导轮出口角,而理论分析此时诱导轮和离心轮的能量匹配不是最佳,不能获得较好的汽蚀性能。经过理论分析,提出降低诱导轮出口角的改进方案,并对诱导轮离心泵流场进行数值模拟,并在试验室进行了试验验证。仿真及试验表明在相同叶轮外形尺寸条件下,提出适当降低诱导轮出口参数的设计方法,虽然泵的扬程和效率略有降低,但泵的抗汽蚀性能得到大幅提高,该方法提高泵的抗汽蚀性能是可行的。     

运载火箭低温输送系统间歇泉特性及抑制方案探究

为研究重型运载火箭液氧管道中的间歇泉现象并设计有效的抑制方法，调研分析了不同领域中间歇泉的研究现状及低温领域间歇泉的特点。揭示了低温推进剂管道中间歇泉的动态特性和产生机理，提出了重型运载火箭间歇泉抑制方法。研究表明：1)低温领域发生间歇泉的管道结构参数、热流输入方式、液体性质与其他领域相比有较大不同；2)减压沸腾是间歇泉产生的主要原因，弹状气泡不是低温管道中产生间歇泉的必要条件；3)间歇泉过程中会出现剧烈的压力降低和突增现象，在恶劣工况下压力波动可达兆帕量级；4)根据重型火箭的管路布局方式，可选择氦气注入或者外界热流引起循环流动的方法来抑制间歇泉。