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Spectral analysis and self-adjusting mechanism for oscillation phenomenon in hydrogen-oxygen continuously rotating detonation engine

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Chinese Journal of Aeronautics 2015年第3期28卷 669-675页

作者： Liu Yusi Wang Yuhui Li Yongsheng Li Yang Wang Jianping center for combustion and propulsion College of Engineering Peking University center for Applied Physics and Technology Peking University State Key Laboratory for Turbulence & Complex Systems Peking University

Abstract The continuously rotating detonation engine （CRDE） is a new concept of engines for air- craft and spacecraft. Quasi-stable continuously rotating detonation （CRD） can be observed in an annular combustion chamber, but the sustaining, stabilizing and adjusting mechanisms are not yet clear. To learn more deeply into the CRDE, experimental studies have been carried out to inves- tigate hydrogen-oxygen CRDE. Pressure histories are obtained during each shot, which show that stable CRD waves are generated in the combustor, when feeding pressures are higher than 0.5 MPa for fuel and oxidizer, respectively. Each shot can keep running as long as fresh gas feeding main- tains. Close-up of the pressure history shows the repeatability of pressure peaks and indicates the detonation velocity in hydrogen-oxygen CRD, which proves the success of forming a stable CRD in the annular chamber. Spectrum of the pressure history matches the close-up analysis and confirms the CRD. It also shows multi-wave phenomenon and affirms the fact that in this case a single detonation wave is rotating in the annulus. Moreover, oscillation phenomenon is found in pressure peaks and a self-adjusting mechanism is proposed to explain the phenomenon.

关键词： Continuously rotatingdetonation Detonation engines Hydrogen-oxygendetonation Self-adjusting mechanism Spectral analysis

Recent advances of hydrogen production through particulate semiconductor photocatalytic overall water splitting

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Frontiers in Energy 2022年第1期16卷 49-63页

作者： Zhi JIANG Zhen YE Wenfeng SHANGGUAN Research center for combustion and Environment Technology Shanghai Jiao Tong UniversityShanghai 200240China

Solar energy-driven photocatalytic water splitting has been investigated for decades to produce clean and renewable green *** this paper,the cutting-edge research within the overall water splitting system is summarized from the one-step photocatalytic overall water splitting(POWS)system to the two-step system and the cocatalysts research in this *** addition,the photocatalytic reaction engineering study is also reviewed which is crucial for future *** mini-review provides a picture of survey of recent progress of relevant overall water splitting system,with particular attention paid to material system and mechanistic breakthroughs,and highlights the challenge and opportunity of the current system.

关键词： photocatalysis overall water splitting hydrogen

Performance and mechanism study for low-temperature SCR of NO with propylene in excess oxygen over Pt/TiO_2 catalyst

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Journal of Environmental Sciences 2010年第9期22卷 1441-1446页

作者： Zhixiang Zhang,Mingxia Chen,Zhi Jiang,Wenfeng Shangguan Research center for combustion and Environmental Technology,Shanghai Jiao Tong University,Shanghai 200240,China. Research center for combustion and Environmental Technology Shanghai Jiao Tong University Shanghai 200240 China

A 0.5 wt.% Pt/TiO2 catalyst was prepared and used for the low-temperature selective catalytic reduction （SCR） of NO with C3H6 in the presence of excess oxygen. The effects of Pt loading and 02 concentration on Pt/TiO2 catalytic performance for low-temperature SCR were investigated. It was found that optimal Pt loading was 0.5 wt.% and excess 02 favored low-temperature SCR of NOx. The mechanism of low-temperature SCR of NO with C3H6 was investigated with respect to the behavior of adsorbed species over Pt/TiO2 at 150~C using in situ DRIFTS. The results indicated that surface nitrosyl species （Pt~＋-NO and Ti3＋-NO） and pt2＋-CO are main reaction intermediates during the interactions of NO, C3H6 and 02. A simplified NO decomposition mechanism for the low-temperature SCR of NO with C3H6 was proposed.

关键词： NO low-temperature SCR Pt/TiO2 in situ DRIFTS

Photocatalytic energy storage ability of TiO_2-WO_3 composite prepared by wet-chemical technique

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Journal of Environmental Sciences 2010年第3期22卷 454-459页

作者： Linglin Cao, Jian Yuan, Mingxia Chen, Wenfeng Shangguan Research center for combustion and Environment Technology, Shanghai Jiao Tong University, Shanghai 200240, China. Research center for combustion and Environment Technology Shanghai Jiao Tong University Shanghai 200240 China

TiO2-WO3 hybrid photocatalysts were prepared using wet-chemical technique, and their energy storage performance was characterized by electrochemical galvanostatic method. TiO2 powder was coupled with WO3 powder, which was used as electron pool and the reductive energy could be stored in. As a result, the prepared TiO2-WO3 had good energy storage ability while pure TiO2 showed no capacity and pure WO3 showed quite low performance. The energy storage ability was affected by the crystal structure of WO3 and calcination temperature. The photocatalyst had better capacity when WO3 had low degree of crystallinity, since its loose structure made it easier for electrons and cations to pass through. The photocatalytic energy storage performance was also affected by the molar ratio of TiO2 to WO3. Energy storage capacity was significantly dependent on the composition, reaching the maximum value at TiO2/WO3 1：1 （mol/mol）.

关键词： photocatalyst TiO2-WO3 energy storage

Hydrothermal Preparation and Photocatalytic Water Splitting Properties of ZrW_2O_8

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Journal of Wuhan University of Technology(Materials Science) 2010年第6期25卷 919-923页

作者：蒋丽上官文峰 Research center for combustion and Environment Technology Shanghai Jiao Tong University

ZrW2O8 was prepared by adjusting Zr：W mole ratio and HCl concentration in hydrothermal reaction *** obtained sample was crystallized in α-ZrW2O8 phase （cubic,P213）,with band gap energy of 4.0 *** properties of photocatalytic water splitting were examined under UV light *** average rate of H2 evolution over 0.3wt% Pt/ZrW2O8 in the presence of CH3 OH as electron donor （ED） was 23.4 μmol/h,while the average rate of O2 evolution over ZrW2O8 in the presence of AgNO3 as electron scavenger （ES） was 9.8 μmol/***,H2 was evolved over 0.3wt% Pt/ZrW2O8 from pure water splitting at a rate of 5.2 μmol/*** study indicated that the band structure of ZrW2O8 was suitable for reducing H ＋ to H2 and oxidizing H2O to *** band structure and photocatalytic water splitting properties of ZrW2O8,different from either ZrO2 （5.0 eV） or WO3 （2.7 eV）,were attributed to the hybridization of W5d and Zr4d in conduction band （CB） as well as the change in crystal structure.

关键词： photocatalyst hydrogen zirconium tungsten oxide hydrothermal preparation

Thermo-physical Characteristics of Nickel-coated Aluminum Powder as a Function of Particle Size and Oxidant

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Chinese Journal of Mechanical Engineering 2016年第6期29卷 1244-1255页

作者： LEE Sanghyup NOH Kwanyoung LIM Jihwan YOON Woongsup Advanced Energy and propulsion Laboratory Department of Mechanical Engineering Yonsei University Missile System Integration / propulsion center Hanwha Corp.

Aluminum particles 15-25 μm in size are widely used in fuel propellants and underwater propulsion systems in national defense research. However, these particles are covered with an aluminum oxide film, which has a high melting point, so ignition is difficult. To improve the ignitability of high-energy aluminum powder and to understand the reaction phenomenon as a function of particle size（15-25 μm, 74-105 μm, and 2.38 mm） and oxidizer（air, CO2, and argon）, the natural oxide films are chemically removed. The particles are then coated with nickel using an electro-less method. The degree of nickel deposition is confirmed qualitatively and quantitatively through surface analysis using scanning electron microscopy/energy dispersive spectroscopy. To characterize the nickel coatings, elemental analysis is also conducted by using X-ray diffraction. Thermogravimetric analysis/differential scanning calorimetry （TGA/DSC） enable comparisons between the uncoated and coated aluminum, and the reaction process are investigated through fine structural analysis of the particle surfaces and cross sections. There are little difference in reactivity as a function of oxidant type. However, a strong exothermic reaction in the smaller nickel-coated aluminum particles near the melting point of aluminum accelerates the reaction of the smaller particles. Explanation of the reactivity of the nickel-coated aluminum depending on the particle sizes is attempted.

关键词： nickel-coated aluminum TGA/DSC aluminum ignition combustion intermetallic reaction

Preparations of TiO_2 film coated on foam nickel substrate by sol-gel processes and its photocatalytic activity for degradation of acetaldehyde

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Journal of Environmental Sciences 2007年第1期19卷 80-85页

作者： HU Hai XIAO Wen-jun YUAN Jian SHI Jian-wei CHEN Ming-xia SHANG GUAN Wen-feng Research center for combustion and Environment Technology Shanghai Jiao Tong University. Shanghai 200030 China

Anatase TiO2 films were successfully prepared on foam nickel substrates by sol-gel technique using tetrabutyl titanate as precursor. The characteristics of the TiO2 films were investigated by XPS, XRD, FE-SEM, TEM and UV-Vis absorption spectra. The photocatalytic activities of TiO2 films were investigated by photocatalytic degradation reactions of gaseous acetaldehyde, an indoor pollutant, under ultraviolet light irradiation. It was found that Ni^2＋ doping into TiO2 films due to the foam nickel substrates resulted in the extension of absorption edges of TiO2 films from UV region to visible light region. The pre-heating for foam nickel substrates resulted in the formation of NiO layer, which prevented effectively the injection of photogenerated electrons from TiO2 films to metal nickel. The TiO2 films displayed high photocatalytic activity for the degradation of acetaldehyde, and were enhanced by calcining the substrates and coating TiO2 films repeatedly. The high activity was mainly attributed to the improvement of the characteristics of substrate surface and the increase of active sites on photocatalyst.

关键词： photocatalyst TiO2 films foam nickel sol-gel acetaldehyde degradation

Measurements of Laminar Burning Velocities of Alternative Fuels:Application in Transport and Aerospace

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Journal of Thermal Science 2023年第2期32卷 503-512页

作者： RICHTER Sandra BRAUN-UNKHOFF Marina NAUMANN Clemens German Aerospace center(DLR) Institute of Combustion TechnologyDepartment of Chemical Kinetics and AnalyticsStuttgart 70569Germany

The laminar burning velocity belongs to the fundamental combustion properties of fuels being a measure for their heat release,flame length,as well as reactivity and combustion stability,and thus,may impact the design of burners and combustion ***,these experimental data are needed for the validation and optimization within the construction and development of detailed chemical kinetic reaction *** this study,an overview of the different applications of fuel characterization regarding the specific area of interest(road transport,aviation,and aerospace)will be *** on the application,effects of different molecular characteristics on the laminar burning velocity are evaluated:the presence of oxygen atoms and the grade of branching in a specific fuel molecule as well as the difference in the type of a chemical bond,here,single and double *** of alternative fuels being discussed in the present study are:(Ⅰ)oxymethylene ether(OMEn)in the field of road transport;(Ⅱ)a paraffinic Alcohol-to-Jet fuel as sustainable aviation fuel;and(Ⅲ)mixtures of ethane or ethene with nitrous oxide as green propellants for rocket propulsion applications.

关键词： laminar burning velocity alternative sustainable fuels road transport aviation fuels green propellants

RE-NiO_(x)(RE=Ce,Y,La)composite oxides coupled plasma catalysis for benzene oxidation and by-product ozone removal

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Journal of Rare Earths 2023年第6期41卷 789-800,I0001页

作者： Yikun Zhang Zhidong Wei Yong Zhu Shanlong Tao Mingxia Chen Zhixiang Zhang Zhi Jiang Wenfeng Shangguan Research center for combustion and Environment Technology School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Plasma-coupled catalysis is a promising volatile organic co mpounds(VOCs) removal technology because of its interactional principles of plasma decomposition and catalytic ***,the problem of harmful by-products is still in trouble.A series of rare earth doped RE-NiO_(x)(RE=Ce,Y,La) composite oxides were synthesized by metal organic frameworks(MOFs)-derived method for coupled plasma oxidation of benzene and by-product ozone *** with plasma alone,the 1%La-NiO_(x)catalyst shows the best enhancement of 50% for benzene conversion with complete removal of a maximum of 800 ppm *** energy consumption for 90% benzene removal efficiency(η90%) is also reduced from 3600 to 1200 J/*** re sults of RE-NiO_(x) catalysts indicate that the doping of La causes interaction and synergistic effect between La and Ni,and the surface oxygen and lattice oxygen with defects play crucial roles in benzene oxidation and ozone decomposition,*** addition,the decomposition mechanism of benzene and ozone under plasma is *** is responsible for the indiscriminate bond breaking in benzene and oxygen to form a variety of organic intermediates and ozone,while the La-NiO_(x) catalyst selectively oxidizes the intermediates to CO_(x)/H2O and decomposes the ozone into oxygen.

关键词： Plasma catalysis Benzene removal By-product ozone control Rare earths doping La-NiO_(x)composite oxide