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Effects of ignition voltage and electrode structure on electric ignition and combustion characteristics of Ammonium Dinitramide(ADN)-based liquid propellants in electric ignition mode in inert gas environment

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Chinese Journal of Aeronautics 2024年第4期37卷 229-242页

作者： Lei LI Guoxiu LI Hongmeng LI Zhaopu YAO Tao ZHANG Jinze WU Shuo ZHANG School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Beijing Institute of Control Engineering Beijing 100190China

Hydrazine is toxic and carcinogenic, which greatly increases the difficulty of application and no longer meets the needs of green aerospace. As a green propellant, the Ammonium Dinitramide(ADN)-based liquid propellant has the advantages of higher specific impulse, being non-toxic,pollution-free, and easy storage. However, an ADN-based space engine in orbit has exposed the problems of high-temperature deactivation of catalysts and cold-start failure. An active ignition technology—electric ignition technology was explored in this paper to break through the technical bottleneck of catalyst deactivation and the inability to a cold start. An experimental system of a constant-volume combustor for the ADN-based liquid propellant based on the electric ignition method was established. The electric ignition and combustion characteristics of the ADN-based liquid propellant in a volume combustor with an electric ignition method were studied. The influencing mechanisms of the ignition voltage and the electrode structure on the electric ignition characteristics of the ADN-based liquid propellant were investigated. An elevation of the ignition voltage could facilitate the ignition process of the ADN-based liquid propellant, curtail electric energy input and heating effect, while exerting an adverse impact on the combustion process of the *** increase in the ignition voltage enhanced the ignition process of the propellant while simultaneously suppressing its combustion process when utilizing mesh electrodes. Compared to the strip electrodes, the mesh electrodes increased the contact area between the electrodes and the propellant,increased the electric energy input power in the electric ignition process, and reduced the ignition delay time. The mesh electrodes could promote the combustion process of the propellant to a certain extent.

关键词： ADN-based liquid propellant Resistive ignition Electrical ignition characteristic Combustion inert gas

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Theoretical study of ullage washing with mixed inert gas in a non-equilibrium state

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Chinese Journal of Aeronautics 2020年第12期33卷 3167-3175页

作者： Shiyu FENG Xiaotian PENG Lei SHAO Yan YAN Chen CHEN Weihua LIU Key Laboratory of Aircraft Environment Control and Life Support of MIIT College of Aerospace EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China College of Aeronautics Chongqing Jiaotong UniversityChongqing 400074China College of Mechanical and Electrical Engineering Xi'an Polytechnic UniversityXi'an 710000China

The Mixed inert gas(MIG)produced by the novel Green On Board inerting gas Generation System(GOBIGGS)mainly consists of carbon dioxide,nitrogen and *** of the large solubility of carbon dioxide in jet fuel compared with nitrogen,the no gas release or equilibrium model could not be employed any *** this paper,first,a mathematical model of the ullage washing was set up to predict the variation of the oxygen concentration on ullage and in the fuel,and the gas evolution and dissolution rate were calculated by Fick's second ***,an experimental apparatus was constructed to verify the accuracy of the ***,the numerical comparisons of ullage washing using Nitrogen Enriched Air(NEA)and MIG are presented under various flow rates and fuel loads,and the result reveals that the variation of the oxygen concentration on ullage is nearly identical whatever the inert gas is NEA or ***,the variation of the oxygen concentration in the fuel is disparate,and the oxygen concentration decreases rapidly if the inert gas is MIG,especially when the fuel load is low or the flow rate of the inert gas is ***,MIG could suppress the rising trend of the oxygen concentration on ullage when the aircraft ascends if the fuel tank is fully washed into an equilibrium state on ground.

关键词： inert gas Mixed inert gas Nitrogen enriched air Non-equilibrium Washing

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Delivery of inert gas through a vertical borehole using inert gas generator: A theoretical study

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International Journal of Mining Science and Technology 2020年第4期30卷 501-510页

作者： Rickard Hansen Sustainable Minerals Institute The University of QueenslandBrisbaneQueensland 4072Australia

The delivery of the inert gas through a vertical borehole using inert gas generator or IGG is *** limitations and/or transient effects are *** the analysis,the borehole diameter,borehole length,type of borehole and partial condensation prior to entering the borehole were varied.A choked flow will occur for a contraction exit or borehole of 0.3 m in diameter if no condensation prior to the contraction *** partial condensation takes place,a borehole diameter of 0.3 m will be possible if almost 50%of the water vapour ***,pressure losses along boreholes with a diameter of 0.3 or 0.4 m are significant and could pose a challenge if trying to mitigate the pressure *** a booster fan prior to the inlet of the 0.4 m lined borehole would still be a *** corresponding case with a 0.5 m borehole presents much more favourable pressure *** 0.5 m diameter lined borehole should be regarded as the lower *** rapid heating of the unlined borehole surface will increase the risk of thermal spallation and possibly imposing *** the mechanisms during gas delivery will increase the likelihood of a successful inertisation.

关键词： GAG inert gas Condensation Pressure loss Choked flow gas velocity Borehole Heat transfer

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A new understanding of inert gas narcosis

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Chinese Physics B 2016年第1期25卷 238-243页

作者：张萌高嶷方海平 Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology Shanghai Institute of Applied Physics Chinese Academy of Sciences School of Information Technology & Engineering Jinzhong University

Anesthetics are extremely important in modem surgery to greatly reduce the patient,s pain. The understanding of anesthesia at molecular level is the preliminary step for the application of anesthetics in clinic safely and effectively. inert gases, with low chemical activity, have been found to cause anesthesia for centuries, but the mechanism is unclear yet. In this review, we first summarize the progress of theories about general anesthesia, especially for inert gas narcosis, and then propose a new hypothesis that the aggregated rather than the dispersed inert gas molecules are the key to trigger the narcosis to explain the steep dose-response relationship of anesthesia.

关键词： cluster inert gas anesthesia narcotic potency

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Synthetic LiFePO4/C without using inert gas

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Chinese Chemical Letters 2007年第3期18卷 337-340页

作者： Guo Rong Hu Xu Guang Gao Zhong Dong Peng Ke Du Yan Jun Liu School of MetaUurgical Science and Engineering Central South University Changsha 410083 China

LiFePO4/C was synthesized by high temperature solid-state method with cheap Fe2O3, LiH2PO4 and glucose as raw materials in absence of inert gas. The sample had ordered olivine-type structure other impurities characterized by the test of X-ray diffraction （XRD）. The charge-discharge test showed the sample could demonstrate 120.5 mAh/g at 0.2C rate with good cyclic capability. The powder microeleetrode cyclic voltammetry test indicated that the redox process of the sample had good reversibility.

关键词： Li-ion batty Cathode material LiFePO4/C inert gas

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Effect of fuel type on the performance of an aircraft fuel tank oxygen-consuming inerting system

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Chinese Journal of Aeronautics 2021年第3期34卷 82-93页

作者： Xiaotian PENG Shiyu FENG Chaoyue LI Chen CHEN Weihua LIU Key Laboratory of Aircraft Environment Control and Life Support of MIIT College of Aerospace EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China

The properties of aviation fuel have a great influence on the performance of oxygenconsuming inerting systems. Based on the establishment of the catalytic inerting process, the flow relationship of each gas component flowing through the catalytic reactor was derived. The mathematical model of the gas concentration in the gas phase of the fuel tank was established based on the mass conservation equation, and the fuel tank model was verified by performing *** results showed that the fuel type exerts a considerably higher influence on the performance of the oxygen-consuming inerting system compared to the corresponding influence on the hollow fiber membrane system, and the relative magnitude of the inerting rates of the four fuel types is RP5 > RP3 > RP6 > JP8. In addition, a higher catalytic efficiency or fuel load rate corresponds to a higher rate of decrease of the oxygen concentration in the gas phase, and the inerting time is inversely proportional to the suction flow rate of the fan. When different fuels are used, the amount of cooling gas and water released from the inerting system are different. Therefore, the influence of fuel type on the system performance should be extensively considered in the future.

关键词： Aviation fuel Catalytic reactions Hollow fiber membrane inert gas Mathematical model

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Influence of shielding gas and non-consumable electrode configuration on weld formation

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China Welding 2021年第4期30卷 17-24页

作者： Aleksandr Savinov Oleg Polesskiy Vladimir Lysak Pavel Krasikov Artem Chudin Volgograd State Technical University Lenin av.28Volgograd400005Russia

The effect of the shielding gas composition and the cathode processing history on the weld formation quality during welding with a non-consumable electrode at high current was studied. The major reasons for pores, “waists” and undercuts formation during welding at high currents and speed are discrete melt movement to the solidification front due to the arc decline from the cathode axis and significant melt overhanging in the pool tail part caused by excessive peak pressure on the discharge axis. Cathode flow dispersion causes the lack of displacement of the molten metal which results in its laminar flow in the weld pool, uniform flow of the metal to the crystallization front and sound weld formation. The melt movement in the weld pool and eventually the welded joint quality is determined by the pressure distribution pattern on the welded metal surface and the anode spot lag from the electrode. It was demonstrated that non-consumable electrode configurations that provide arcing with a diffuse cathode spot and increased helium concentration in the inert atmosphere during welding with a conical electrode allow sound weld formation.

关键词： tungsten inert gas welding non-consumable electrode inert gas weld seam formation

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Development and Making of New Jewellery Palladium Based Alloys at JSC ＂Krastsvetmet＂

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贵金属 2012年第A1期33卷 279-280页

作者： YEFIMOV V. N. MAMONOV S. N. SHULGIN D. R. YELTSIN S. I. JSC Krastsvetmet Krasnoyarsk Russia

Complex of research and development work aimed at implementation of jewellery palladium based alloys technology has been carried out at JSC Krastsvetmet. A range of palladium alloys jewellery fabrication has been organized. Compositions of a number of jewellery palladium alloys grade 850, 900, 950 and 990 have been proposed, their production and application in jewellery manufacture has been organized. To produce palladium alloys induction melting in inert atmosphere and melt pouring into a copper mould has been used. The ingots heat treatment conditions, as well as semi-finished jewelry plastic deformation parameters have been determined.

关键词： jewellery palladium alloys induction melting inert gas plastic deformation jewellery products

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