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1.
一种富氧中空纤维膜组件的温度特性   总被引:2,自引:0,他引:2       下载免费PDF全文
 通过实验研究温度对中空纤维膜组件氧/氮分离性能的影响,结果表明温度能够明显影响膜的分离特性,并且不影响富氧浓度,可以通过控制膜组件的使用温度来增加富氧产量.  相似文献
2.
静电拉伸空间薄膜反射镜面形控制机理研究   总被引:1,自引:1,他引:0  
薄膜反射镜将解决反射镜孔径与重量相互制约的问题.采用静电拉伸法控制薄膜反射镜面形,具有结构简单、反射镜面形易于控制等优点,其原理为利用静电场上库仑力作用使薄膜产生面形变化,生成所需的光学曲面.由于薄膜变形力学,以及静电场理论的复杂性,目前薄膜成形及其面形控制在理论分析上仍未有定量的结果.本文主要以单电极静电场中的薄膜反射镜面形为考察因素,通过数值计算的方法得到薄膜反射镜上的静电力分布,运用有限元分析获得该分布下的反射镜面形,并将其与理想面形进行比较.提出采用多电极闭环控制可获得更高的控制精度,对静电拉伸薄膜的研究具有一定的指导意义.  相似文献
3.
大型太阳帆薄膜折叠及展开过程数值分析   总被引:1,自引:0,他引:1  
针对深空太阳帆帆面薄膜折叠方式及太阳帆空间展开过程的优化问题,在叶内折叠、叶外折叠方式的基础上,提出了一种斜叶外折叠方式,并通过建立不同的参数模型,利用ANSYS/LS-DYNA有限元软件对5种折叠模型展开过程进行了力学分析.分析结果表明,新提出的斜叶外折叠方式是较适合空间应用的太阳帆帆面折叠方式.太阳帆在空间展开过程中帆面应力与展开速度、折叠宽度等因素相关,帆面与支撑杆连接的顶点区域是整块帆面应力最大的区域,应重点进行加固.研究结果将为大型太阳帆薄膜材料选择及结构设计提供重要依据.  相似文献
4.
流道弯曲度对微重力膜式水气分离性能的影响   总被引:1,自引:1,他引:0       下载免费PDF全文
开展微重力膜式水气分离性能仿真研究,对水气分离技术设计与优化具有重要意义。针对微重力入口边界气液界面多尺度问题(入口流型问题)提出了基于界面概率近似方法的欧拉双流体模型,采用动量源项法解决几何多尺度问题(分离膜边界问题),为仿真研究提供了有效的入口及渗透边界。研究了典型工作参数下流道弯曲度对膜分离性能的影响,并从流动形态和作用力贡献2个方面分析了影响机理。结果表明:膜分离性能随流道弯曲度增大而降低,影响程度与入口含气率相关;直流道适于选作膜式静态水气分离器主要流道形式。  相似文献
5.
 以采用壳体非线性无矩理论所确定的碟形弹簧薄膜位移与薄膜应力作为初始状态,采用壳体线性有矩理论对碟形弹簧进行了弯曲位移与弯曲应力分析.分析表明:与薄膜应力相比,弯曲应力是不能略去的;而与薄膜位移相比,弯曲位移是可以略去的.因此,对碟形弹簧而言,以壳体非线性无矩理论确定位移是合理的,而以壳体线性有矩理论确定附加弯曲应力也是可行的,同时也是必要的.  相似文献
6.
The essential reason of the lobed-pumpkin shaped super-pressure balloon to withstand against the high pressure is that the local curvature of the balloon film is kept small. Recently, it has been found that the small local curvature can also be obtained if the balloon is covered by a diamond-shaped net with a vertically elongated shape. The development of the super-pressure balloon using this method was started from a 3-m balloon with a polyethylene film covered by a net using Kevlar ropes. The ground inflation test showed the expected high burst pressure. Then, a 6-m and a 12-m balloon using a polyethylene film and a net using the Vectran were developed and stable deployment was checked through the ground inflation tests. The flight test of a 3000 m3 balloon was performed in 2013 and shown to resist a pressure of at least 400 Pa. In the future, after testing a new design to relax a possible stress concentration around the polar area, test flights of scaled balloons will be performed gradually enlarging their size. The goal is to launch a 300,000 m3 super-pressure balloon.  相似文献
7.
In microgravity, one of the major challenge encountered in biological life support systems (BLSS) is the gas–liquid transfer with, for instance, the necessity to provide CO2 (carbon source, pH control) and to recover the evolved O2 in photobioreactors used as atmosphere bioregenerative systems.  相似文献
8.
In recent years, the study of semi-rigid airship has revived with the development of airships. Semi-rigid airships have some characteristics of rigid airships and non-rigid airships. Due to the flexibility of the envelope of the non-rigid airship, the variation of the temperature of the inner gas will lead to its structure deformation and affect its flight altitude. This paper develops the structural mechanics model, thermodynamic model and dynamic model of the semi-rigid airship, based on which nonlinear finite element analysis is employed for geometrically nonlinear deformation of the airship upper film in consideration of thermodynamics and structural mechanics coupling. Based on the thermal-structural interaction, the thermal characteristics and flight performances of the airship during floating flight are investigated. The 3-D solar radiation and temperature distribution of the airship skin and the temperature variation of the inner gas are presented to investigate the thermal performance of the airship, flight velocity, acceleration and flight altitude are simulated to investigate the flight performance, and the variations of the volume and pressure difference of the inner gas are calculated to provide a basis for structure design. The results of the simulation can be referenced for the design of the semi-rigid airship, and can be used for the further study on the attitude control of the airship during its floating flight.  相似文献
9.
The super-pressure balloon (SPB) has been expected to be a flight vehicle that can provide a long flight duration to science. Since 1997, we have developed the SPB. Now we are at the phase of developing an SPB of a practical size. In 2009, we carried out a test flight of a pumpkin-shaped SPB with a 60,000 m3 volume. The undesirable result of this flight aroused us to resolve the deployment instability of the pumpkin-shaped SPB, which has been known as one of the most challenging issues confronting SPB development. To explore this deployment issue, in 2010, we carried out a series of ground tests. From results of these tests, we found that an SPB design modified from pumpkin, named “tawara”, can be a good candidate to greatly improve the deployment stability of the lobed SPB.  相似文献
10.
As NASA implements the U.S. Space Exploration Policy, life support systems must be provided for an expanding sequence of exploration missions. NASA has implemented effective life support for Apollo, the Space Shuttle, and the International Space Station (ISS) and continues to develop advanced systems. This paper provides an overview of life support requirements, previously implemented systems, and new technologies being developed by the Exploration Life Support Project for the Orion Crew Exploration Vehicle (CEV) and Lunar Outpost and future Mars missions. The two contrasting practical approaches to providing space life support are (1) open loop direct supply of atmosphere, water, and food, and (2) physicochemical regeneration of air and water with direct supply of food. Open loop direct supply of air and water is cost effective for short missions, but recycling oxygen and water saves costly launch mass on longer missions. Because of the short CEV mission durations, the CEV life support system will be open loop as in Apollo and Space Shuttle. New life support technologies for CEV that address identified shortcomings of existing systems are discussed. Because both ISS and Lunar Outpost have a planned 10-year operational life, the Lunar Outpost life support system should be regenerative like that for ISS and it could utilize technologies similar to ISS. The Lunar Outpost life support system, however, should be extensively redesigned to reduce mass, power, and volume, to improve reliability and incorporate lessons learned, and to take advantage of technology advances over the last 20 years. The Lunar Outpost design could also take advantage of partial gravity and lunar resources.  相似文献
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