低温推进剂地面加注停放阶段蒸发量分析

建立了一种可以描述低温推进剂加注、停放过程的计算模型,分析了影响低温推进剂加注停放阶段蒸发的主要因素。研究表明:为缩短发射组织时间、优化加注流程、提升推进剂品质,在全系统能力范畴内,低温推进剂加注过程应提高推进剂加注速度,降低推进剂加注温度,尽量减小外界环境漏热率,并适当增加系统排气能力。     

低温液体运载火箭推进剂加注过程分析

介绍了国外运载火箭典型低温贮箱的推进剂加注流程,讨论了影响低温推进剂加注特性的主要因素,建立了一种可以描述低温推进剂加注过程的计算模型,结合试验数据验证了模型预示加注过程贮箱推进剂平均温度、气枕压力等关键参数的准确性,进一步依据仿真和试验结果分析了低温推进剂加注过程的典型特性。     

火星探测任务中低温推进剂弹性保障策略

为确保在当年发射窗口内具备多次组织加注、发射的机会,成功实施火星探测任务,亟需解决低温推进剂弹性保障问题。结合任务特点,分析了第一窗口准时发射、未加注前推迟发射、加注后推迟发射和加注泄回后重新组织发射4种发射情况;据此建立了低温推进剂筹措模型,识别了推进剂保障关键点;结合生产实际制定了多窗口保障策略,即通过统筹推进剂筹措计划、优化系统准备工作和提升筹措过程可靠性,实现低温推进剂弹性保障。实践证明,弹性保障策略实现了低温推进剂的有效、可靠保障。     

过冷推进剂温度和加注量精确控制方案及对火箭影响分析

针对某运载器提出的高精度低温推进剂温度和加注量精确控制要求,研究了高精度温度和加注量控制方案,对温度偏差和加注量偏差给火箭总体性能带来的影响进行了分析,给出了相关建议,为后续该类加注系统应用于移动式加注现场提供支撑。     

火箭发射场新型低温加注系统加注过程仿真研究

以某火箭发射场新型液氧推进剂地面加注系统为对象,将整个系统简化为地面储罐、箭上贮箱、输送管路,分别建立热力学模型,并依据边界条件耦合分析,实现了加注过程的瞬态仿真。针对液氧加注过程开展了计算分析,并就影响加注性能的主要因素开展了变工况分析与讨论。     

肼类推进剂废水处理方法及等离子体的应用进展

液体火箭加注肼类推进剂后,清洗推进剂运输车辆会产生百吨级废水,及时有效地处理含有毒物质的肼类推进剂废水,可以解决因二次污染带来的环保问题。介绍了目前常用的肼类推进剂废水处理方法、废水组分及含量分析方法以及等离子体技术在处理含有机物废水中的应用。针对目前等离子体技术在肼类推进剂废水处理中应用较少的现状,建议从机理分析、等离子体参数设计和优化以及研制新型实验装置方面展开研究,解决肼类推进剂废水带来的发射场安全问题,满足新形势下航天发射任务的需求。     

一种新型低温真空软管的设计

随着低温火箭运载能力不断发展,推进剂的加注流量要求也在不断提高。原有的小通径加注管道已不满足大流量加注需求,必须设计一种大通径低温推进剂输送管道,这面临着大通径管道总成技术、绝热接头设计技术等难题。通过介绍在特定狭小空间内,为适应低温推进剂加注连接器的对接、脱落位置变化,设计了一种新型大通径低温真空多层绝热软管,包括管道总体方案的选型、关键参数的计算等。该方法已被应用于某低温推进剂输送管道的设计和加工,并通过了实际运行工况的试验考核,验证了设计方法的正确性,对同类管道设备的设计具有一定的参考价值。     

氙气泄漏检测设备的性能测试

新型空间电推进技术具有高比冲、小推力、长寿命等优点,将广泛应用于新一代卫星推进系统中。由于氙气具备较低的电离能和较高的原子能量,是电推进主要的推进剂。针对卫星电推进系统氙气供给子系统在加注氙气过程中可能造成的泄漏,研制了氙气泄漏检测设备。通过介绍设备结构、技术指标、检测方法等相关技术内容,给出了设备的性能测试结果。测试结果表明:研制的氙气泄漏检测设备完全能够满足电推进系统加注氙气时泄漏检测的技术要求。     

低温液氢加注系统间歇泉现象风险评估研究

分析了液氢加注系统竖直管路内间歇泉现象产生的过程,总结了间歇泉现象产生的原因与危害性.采用改进的风险矩阵法,对间歇泉现象产生时给加注管路以及贮箱带来的危害进行了风险评估.为提前发现液氢加注过程中间歇泉现象引起的风险及风险发生后的风险转移提供理论参考,从而减小风险对液氢加注系统的影响.     

低温加注控制技术

在总结运载火箭低温加注现行控制技术的基础上，介绍了低温加注控制的特点，并阐述了参数测量及信号变换，传输技术，分布式控制技术，数字ＰＩＤ调节技术和应用。     

VLE data for CO2-CF2Cl2, N2-CO2, N2-CF2Cl2 and N2-CO2-CF2Cl

Knowledge about vapour-liquid (VLE) is required as a basis of reliable calculations for separation processes. Correlations available for the prediction of T, p, x, y data are less accurate for mixtures at high pressures and mixtures containing supercritical components. The results of VLE experiments are reported and compared with data calculated with equations of state.     

Thermal diffusion in binary mixtures H2-CCl2F2 and H2-CHClF2

Thermal diffusion coefficients were measured in two gaseous mixtures, in which one component was close to the critical temperature, in the pressure range (19.6–127.4)·10⁴ N/m² and at a freon concentration of 0.25–0.8.     

Preparation of ZrO2-CeO2 and HfO2-CeO2 nanopowders

We prepared weakly agglomerated powders of ZrO₂-CeO₂ and HfO₂-CeO₂ solid solutions 5–8 nm in particle size, consisting of monoclinic and tetragonal phases. After heat treatment at 1200°C, the crystallite size was 30 and 14 nm, respectively. We also examined the effect of precipitate freeze drying on the crystallization of hafnia-based solid solutions containing up to 20 mol % CeO₂.     

Comparison of the Electronic Structures of La2CuO4, Sr2CuO2Cl2, and Sr2CuO2F2

First-principles cluster calculations are reported of the local electronic structure of the three compounds: La₂CuO₄, Sr₂CuO₂Cl₂, and Sr₂CuO₂F₂. The copper ${\text{3d}}_{x^2 - y^2 } $ and the planar oxygen 2p _σ atomic orbitals exhibit a similar degree of covalency. The out-of-plane orbitals, however, are quite different with the ${\text{3}}d_{3z^2 - r^2 } $ atomic orbital lowered significantly in energy for chlorine and fluorine apical positions.     

Radial GRIN glasses in Li2O-Na2O-Al2O3-TiO2-SiO2 systems

A series of GRIN glass rods have been developed in Li2O-Na2O-Al2O3-TiO2-SiO2 systems. Negative radial refractive index profiles were generated by exchanging Na+ for Li+ ions in these glass rods. It has been observed that TiO2 plays a vital role in increase in the profile depth and maximum change in the refractive index because of its ambivalent nature. Change in the refractive index can be further increased by increasing the concentration of exchanging cation in the base glass.     

Thermoelectric power of single-phase samples of Tl2CaBa2Cu2O y and Ba2CaSr2Cu2O y

Single-phase 2122 samples of thallium and bismuth superconductors were made by the precursor matrix method. The thermopower of these samples was measured in the temperature range 250 K-T _c . The thermopower was positive and decreased linearly with increasing temperature aboveT _c (onset). The exponential enhancement of thermopower seen in the undoped and doped YBCO was not observed in these samples. The linear variation of thermopower can be explained on the basis of either a two-band model or a narrow band model.     

Si_2N_2O-Al_2O_3-La_2O_3和Si_2N_2O-Al_2O_3-CaO系统的亚固相关系

本文给出了 Si_2N_2O-Al_2O_3-La_2O_3和 Si_2N_2O-Al_2O_3-CaO 系统的亚固相图。实验结果表明:在 Si_2N_2O-Al_2O_3-CaO 系统中有一个未知结构的新化合物 CaO·Si_2N_2O,在3CaO·Si_2N_2O 和3CaO·Al_2O_3两化合物之间形成连续立方固溶体。而 Si_2N_2O-Al_2O_3-La_2O_3系统中则没有发现新化合物。在两个系统的富 Si_2N_2O区,过量的 Si_2N_2O 与 La_2O_3和 CaO 分别反应形成 Si_3N_4与 La_(10)[SiO_4]_(?)N_2(H-相)(和 CaSiO_3。所研究的这两个三元系统中,分别形成了如下几个四元相容性区。在 Si_2N_2O-Al_2O_3-La_2O_3系统内有:H-Si_3N_4-La_2O_3·Si_2N_2O-La_2O_3·Al_2O_3;H-Si_3N_4-La_2O_3·Al_2O_3-La_2O_3·11 Al_2O_3;H-Si_3N_4-La_2O_3·11 Al_2O_3-Al_2O_3;H-Si_3N_4-Al_2O_3-O′s.s;H-Si_3N_4-O′s.s-Si_2N_2O在 Si_2N_2O-Al_2O_3-CaO 系统内有:Si_3N_4-CaSiO_3-CaO·Si_2N_2O-3CaO·Al_2O_3;Si_3N_3-CaSiO_3-3CaO·Al_2O_3-2CaO·Al_2O_3·SiO_(?);Si_(?)N_(?)-CaSiO_3-2CaO·Al_2O_3·SiO_2-Al_2O_3;Si_3N_4-CaSiO_3-Al_2O_(?)-O′s.s;Si_3N_4-CaSiO_3-O′s.s-Si_(?)N_(?)O     

Elastic and Electronic Properties of Superconducting CaPd 2 As 2 and SrPd 2 As 2 vs. Non-superconducting BaPd 2 As 2

The first-principles calculations were performed to predict the elastic and electronic properties of the superconducting ThCr₂Si₂-type phases CaPd₂As₂ and SrPd₂As₂ in comparison with the non-superconducting CeMg₂Si₂-type phase BaPd₂As₂. Besides, the same properties were compared for CeMg₂Si₂- and ThCr₂Si₂-type polymorphs of BaPd₂As₂. We found that all these phases are mechanically stable and belong to soft materials with low hardness. The near-Fermi region is formed by the valence states of the blocks [Pd₂As₂] with decisive contributions of Pd 4d states. The values of N(E _F) increase in the sequence: CaPd₂As₂ < SrPd₂As₂ < BaPd₂As₂, i.e. in the reverse sequence relative to the transition temperatures T _C. Thus, the change in T _C cannot be explained by the electronic factor, i.e. by the simple correlation T _C～N(E _F). Most likely the decrease in T _C in the sequence CaPd₂As₂ → SrPd₂As₂ and the absence of a superconducting transition in BaPd₂As₂ are related to the structural factors and the peculiarities of the electron–phonon coupling mechanism.