Progress in Technology of Main Liquid Rocket Engines of Launch Vehicles in China

Liquid propellant rocket engines for a launch vehicle are an essential aerospace technology, representing the advanced level of hi-tech in a country. In recent years, China’s aerospace industry has made remarkable achievements, and liquid rocket engine technology has also been effectively developed. In this article, the development processes of China’s liquid rocket engines are discussed. Then, the performance features of China’s new generation liquid rocket engines as well as the flight tests of the new-generation launch vehicles are introduced. Finally, the development direction and the most recent progress of the next generation large-thrust liquid rocket engine is presented.

Research on Key Technologies for Reusable Liquid Rocket Engines

Based on current research,the development trend of reusable liquid rocket engines was analyzed.Key technologies and research focuses of the reusable liquid rocket engine have been analyzed and summarized,and then suggestions on the development of future key technologies are proposed.

Liquid metal as an efficient protective layer for lithium metal anodes in all-solid-state batteries

Lithium metal batteries with inorganic solid-state electrolytes have emerged as strong and attractive candidates for electrochemical energy storage devices because of their high-energy content and safety.Nonetheless,inherent challenges of deleterious lithium dendrite growth and poor interfacial stability hinder their commercial application.Herein,we report a liquid metal-coated lithium metal(LM@Li)anode strategy to improve the contact between lithium metal and a Li6PS5Cl inorganic electrolyte.The LM@Li symmetric cell shows over 1000 h of stable lithium plating/stripping cycles at 2mA cm^(-2) and a significantly higher critical current density of 9.8 mAcm^(-2) at 25°C.In addition,a full battery assembled with a high-capacity composite LiNbO3@-LiNi_(0.7)Co_(0.2)Mn_(0.1)O_(2)(LNO@NCM721)cathode shows stable cycling performance.Experimental and computational results have demonstrated that dendrite growth tolerance and physical contact in solid-state batteries can be reinforced by using LM interlayers for interfacial modification.

Simulation and Experiment for Oxygen-enriched Combustion Engine Using Liquid Oxygen to Solidify CO2

For capturing and recycling of CO2 in the internal combustion engine, Rankle cycle engine can reduce the exhaust pollutants effectively under the condition of ensuring the engine thermal efficiency by using the techniques of spraying water in the cylinder and optimizing the ignition advance angle. However, due to the water spray nozzle need to be installed on the cylinder, which increases the cylinder head design difficulty and makes the combustion conditions become more complicated. In this paper, a new method is presented to carry out the closing inlet and exhaust system for internal combustion engines. The proposed new method uses liquid oxygen to solidify part of cooled CO2 from exhaust system into dry ice and the liquid oxygen turns into gas oxygen which is sent to inlet system. The other part of CO2 is sent to inlet system and mixed with oxygen, which can reduce the oxygen-enriched combustion detonation tendency and make combustion stable. Computing grid of the IP52FMI single-cylinder four-stroke gasoline-engine is established according to the actual shape of the combustion chamber using KIVA-3V program. The effects of exhaust gas recirculation （EGR） rate are analyzed on the temperatures, the pressures and the instantaneous heat release rates when the EGR rate is more than 8%. The possibility of enclosing intake and exhaust system for engine is verified. The carbon dioxide trapping device is designed and the IP52FMI engine is transformed and the CO2 capture experiment is carried out. The experimental results show that when the EGR rate is 36% for the optimum EGR rate. When the liquid oxygen of 35.80-437.40 g is imported into the device and last 1-20 min, respectively, 21.50-701.30 g dry ice is obtained. This research proposes a new design method which can capture CO2 for vehicular internal combustion engine.

Theoretical study on the ideal open cycle of the liquid nitrogen engine

This article described the characteristics of the liquid nitrogen engine's ideal open cycle.Using two interconnecting strokes to achieve the power output can mitigate the trade-off between high efficiency and the potential mechanical complexity of multiple-cylinder engines. The total specific energy of the binary media (methane-nitrogen) cycle system could be much higher than the unitary medium (liquid nitrogen) cycle system. By theoretical analysis, the reasonably acceptable driving range proved the feasibility of the liquid nitrogen engine used for supplying power for a lightweight car.

The potential of ionic liquids in biopharmaceutical engineering

Biopharmaceuticals,such as proteins,peptides,nucleic acids and vaccines,bring about great hopes for the prevention and treatment of various diseases,but the industrialization of these products still faces challenges such as structural instability,inefficient bioactivity and low bioavailability.Ionic liquids(ILs),the marvelous solvent media with inimitable and tunable properties,may provide alternative solutions to overcome the above problems of biopharmaceutical industry.Progress has gradually been made through studies by combination of ILs with biomacromolecules.The applications involved the stabilization,protection,and delivery of biopharmaceuticals.Recent trends are being forwarded to using ILs in vaccines and nucleic acid drugs.However,challenges remain on the toxicity and safety issues.Besides,the cost of adding ILs to the benefits of biopharmaceuticals need to be considered.

The opportunities and challenges of ionic liquids in perovskite solar cells

Metal halide perovskite solar cells(PSCs)have shown great potential to become the next generation of photovoltaic devices due to their simple fabrication techniques,low cost,and soaring power conversion efficiency(PCE).However,mismatched with the quickly updated PCEs,the improvement of device stability is challenging and still remains a critical hurdle in the path to commercialization.Recently,ionic liquids(ILs)have been found to play multiple roles in obtaining efficient and stable PSCs.These ILs usually consist of large organic cations and organic or inorganic anions,which have weak electrostatic attraction and are generally liquid at around 100℃.ILs are almost non-volatile,non-flammable,with high ionic conductivity and excellent thermal and electrochemical stability.The roles of ILs in PSCs vary with their composition,that is,the types of anions and cations.In this review,we summarize the roles of anions and cations in terms of precursor solutions,additives,perovskite/charge transport layer interface engineering,and charge transport layers.This article aims to set up a structure–property-stability-performance correlations conferred by the IL in PSC and provide assistance for the anion and cation selection for improving the quality of perovskite film,optimizing interface contact,reducing defect states,and improving charge extraction and transport characteristics.Finally,the application of IL in PSCs is discussed and prospected.

Safety Analysis of Liquid Rocket Engine Using Bayesian Networks

Safety analysis for liquid rocket engine has a great meaning for shortening development cycle, saving development expenditure and reducing development risk. The relationship between the structure and component of liquid rocket engine is much more complex, furthermore test data are absent in development phase. Thereby, the uncertainties exist in safety analysis for liquid rocket engine. A safety analysis model integrated with FMEA(failure mode and effect analysis) based on Bayesian networks (BN) is brought forward for liquid rocket engine, which can combine qualitative analysis with quantitative decision. The method has the advantages of fusing multi-information, saving sample amount and having high veracity. An example shows that the method is efficient.

Interfacial charge-transfer engineering by ionic liquid for high performance planar CH3NH3PbBr3 solar cells

The energy barrier at the CH3NH3Pb Br3/TiO2interface hinders the electron transfer from CH3NH3Pb Br3to compact TiO2（cp-TiO2）.Ionic liquid（IL）,that forms dipoles pointing away from TiO2,can adjust the work function of TiO2resulting in suitable energy level for charge transfer from CH3NH3Pb Br3to TiO2.The time-resolved photoluminescence spectroscopy（TRPL）measurements confirm faster electron transfer from the CH3NH3Pb Br3film to TiO2after modification by IL.Solar cells based on IL modified cp-TiO2demonstrate efficiency of～6%,much higher than the devices（0.2%）fabricated using untreated cp-TiO2as the electron transport layer.

Review on the Progress and Issues in Liquid Tank Sloshing of Ships

With the development of large liquid cargo ships,liquid tank sloshing has gradually become a hot research topic in the area of shipping and ocean Engineering.Liquid tank sloshing,characterized by strong nonlinearity and randomness,not only affects the stability of the ship but also generates a huge impact force on the wall of the tank.To further investigate liquid tank sloshing,a comprehensive review is given on the research process of the most focused subjects of liquid sloshing.Summarizing the existing research will help to identify issues in the current field and provide useful references.The methods for investigating sloshing,the research progress and the situations worldwide are discussed.The advantages and defects of experiments and numerical simulations are also explored.The problems which need to be explored in the future are subsequently proposed.

Numerical and Experimental Characterizations of SiFRP Ablator for the Application to Liquid Rocket Engine Combustors

The ablative material is supposed to be one of good candidates for LRE （liquid rocket engine） combustion chamber to achieve both high reliability and low cost and a numerical analysis for the ablator is considered to be a potentially efficient tool to reduce cost as well. So far, ablators have been successfully applied for many SRM （solid rocket motors）, but the application to LRE is still quite limited in Japan. The authors believe that this is primarily because of the unpredictable nature of the heat load from combustion gases to the combustor wall. Indeed, reliable thermal design of ablative combustion chamber, namely reliable prediction of thermal performance, needs both reliable heat load model and reliable ablator response model. This paper elaborates our research activities and our recent research findings.

重复使用运载火箭液体动力技术发展

重复使用是未来运载火箭更新换代的技术发展趋势,是降低航天发射成本、实现规模化航天发射的有效途径。重点概述了国内外垂直起降重复使用运载火箭动力技术的发展现状,分析了垂直起降重复使用运载火箭发射和回收全任务剖面,总结了垂直起降重复使用运载火箭动力技术的特点,包括宽范围入口压力多次启动技术、大范围快速高精度推力调节技术、故障诊断及健康管理技术、状态检测与维修维护技术等。

液体火箭发动机健康监控技术研究进展

液体火箭发动机健康监控技术作为保障运载火箭安全、可靠发射的核心关键技术,经过几十年的发展,有力推动了航天事业的进步。介绍了液体火箭发动机健康监控技术中故障检测与诊断、容错控制与健康监控系统研制等技术的研究现状与发展趋势;梳理了健康监控领域面临的重难点问题,并提出相应的解决方案。分析展望了液体火箭发动机健康监控技术未来发展趋势,为从事火箭发动机健康监控技术研究的科研人员提供参考。

合成气乙二醇产品质量提升技术综述

总结合成气制乙二醇产品质量提升的4种技术手段:液相加氢,精馏加碱,产品塔釜加药剂和离子交换树脂吸附,分析4种方法的作用原理和效果,提出产品质量提升的根本在于加氢催化剂性能的提高,液相加氢需进一步提高催化剂活性,从而简化生产工艺。综述对乙二醇生产具有一定的借鉴作用。

基于Hessian局部线性嵌入和MLP-Mixer的液体火箭发动机涡轮泵轻量化故障诊断框架

作为液体火箭发动机推进剂输送系统的关键部件,涡轮泵的运行状态直接影响着整个运载系统的性能,然而,现有的故障诊断方法往往面临特性参数选择片面及计算复杂度高等问题。针对上述局限,提出了面向涡轮泵的轻量化故障诊断框架。所提方法利用Hessian局部线性嵌入算法对信号时域、频域及时频特征进行降维,并引入一种轻量化的深度学习模型MLP-Mixer作为分类器,进而实现不同故障状态的辨识。采用某型号涡轮泵试车数据验证了所提方法的有效性,结果表明,该方法能够在保障诊断精度的同时有效降低计算复杂度,提高诊断效率。

Ga基液态金属在生物医学应用的研究进展

介绍了Ga基液态金属(GaLMs)的主要理化性质,这些性质为GaLMs应用奠定了基础。从诊断和治疗两方面总结了GaLMs在生物医学领域应用的进展,包括可穿戴柔性传感、生物成像、肿瘤治疗及其他疾病治疗。围绕GaLMs的结构优化、长期生物安全性及诊疗一体化等,讨论了GaLMs在生物医学应用中面临的挑战和未来的发展方向。

混凝土路面乙醇流淌燃烧特性试验研究

为了探究液体燃料泄漏燃烧特性,以混凝土为底板开展点燃与非点燃条件下乙醇流淌火试验,测量并分析了扩散直径、火焰温度、单位面积燃烧速率等关键参数。根据泄漏速率与燃烧速率的相对关系,将乙醇流淌火燃烧过程划分为扩散燃烧阶段与准稳态燃烧阶段,并分别建立了上述两阶段的扩散直径预测理论模型。扩散直径、火焰温度均随乙醇泄漏速率(40~80 mL/min)增加而增大。其中,当泄漏速率为80 mL/min时,火焰温度峰值最高(约为860℃)。此外,在本试验中乙醇流淌火单位面积燃烧速率约为乙醇油池火的68%,这主要是因为乙醇流淌燃烧过程中存在热损失并且乙醇流淌火的火焰热辐射吸收程度更低。

两相流振荡流动特性的可视化实验研究

为了解决活塞内冷油腔中气液两相流的振荡传热问题,设计并搭建了由柴油机改装的往复振荡实验装置,利用高速摄像技术对内冷油腔实验件中气液两相流的振荡流动过程进行了可视化观测实验,分析在不同转速和液体填充率下实验件中气液两相流在起振阶段和充分振荡阶段的振荡流动形态。结果表明:在起振阶段,气液两相的分界面明显,没有强烈的湍流混合运动,在充分振荡阶段,液体的运动规律及流动形态呈周期性变化;转速主要影响气液两相流的湍流强度,填充率主要影响气液两相流的流动形态。研究结果揭示了内冷油腔中气液两相流的振荡流动规律,可为高强化活塞的结构优化设计提供参考。

某液体火箭发动机用起动器峰值压力时间超差故障研究

针对某液体火箭发动机用起动器峰值压力时间超差故障,进行了原因分析,提出了改进措施并对其有效性进行了试验验证。结果表明:造成起动器峰值压力时间超差故障的原因为起动器内膜片与端盖间的焊接强度不足,在高温燃气冲击下膜片过早脱落、烧蚀,从而导致压力提前泄放。提出将1圈焊接改进为2圈焊接、将点焊改进为连续焊接,焊接后增加气密性及承压性能检测,以及加强削弱槽深度检测等改进措施。验证试验表明上述改进措施可有效避免起动器出现峰值压力时间超差故障。

N235从废催化剂沉钒废液中回收钒

这是一篇冶金工程领域的论文。针对陕西某炼锌厂废催化剂的沉钒废液,通过溶剂萃取法除杂并回收沉钒废液中的钒,考查N235体积分数、萃取相比、萃取时间、萃取级数等对钒萃取率的影响。结果表明:采用30%N235+5%TBP+65%的磺化煤油的萃取体系经过四级逆流萃取,萃取相比V_(O)/V_(A)=2∶1,萃取时间t=5 min,钒的萃取率为95.68%;反萃取剂Na_(2)CO_(3)体积分数为5%,反萃相比V'_(O)/V'_(A)=4∶1,反萃时间t=4 min,经三级逆流反萃取,钒的反萃取率为98.25%。