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Stability and Emission Characteristics of Ammonia/Air Premixed Swirling Flames with Rotating Gliding Arc Discharge Plasma

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SSRN 2022年

作者： Ju, Rongyuan Wang, Jinhua Zhang, Meng Mu, Haibao Zhang, Guanjun Yu, Jinlu Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China State Key Laboratory of Electrical Insulation and Power Equipment School of Electrical Engineering Xi’an Jiaotong University Xi’an710049 China School of Aeronautics Engineering Air Force Engineering University Xi’an710038 China

Ammonia received increased attention as a carbon-free fuel and hydrogen carrier. Poor combustion stability and high NOx emission are the main issue for ammonia combustion. Effects of rotating gliding arc (RGA) discharge plasma on the flame stability and NOx emission of NH3/air premixed swirling flames were investigated. The discharge characteristics of the RGA were studied. The flame stabilization mechanisms by plasma were revealed and analyzed according to the flame structure transition and the distribution of key intermediate OH radicals. The NOx emissions were measured by the Gasmet DX4000 Fourier Transform Infrared (FTIR) gas analyzer. Results showed that the RGA discharge plasma can enhance the stability and extend the lean blow-off (LBO) limits from 0.6 to approximately 0.43-0.57. A hysteresis phenomenon about the transition between the lift-off flame and the attached flame was observed without plasma and disappeared with plasma activation. The plasma reduces NO and NO2 emissions mainly due to the kinetic and cracking effects of plasma. Extremely low NO emission below 300 ppm can be observed for very lean ammonia flames with an equivalence ratio (f) lower than 0.6, which are stabilized by plasma, while a large amount of unburned NH3 emission is accompanied. © 2022, The Authors. All rights reserved.

关键词： Ammonia

Influence of Bentonite on Copper Corrosion in Simulated Repository Electrolyte

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SSRN 2024年

作者： Ning, Zhiyuan Zhou, Qulan Li, Na Macdonald, Digby D. State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Departments of Nuclear Engineering and Materials Science and Engineering University of California at Berkeley BerkeleyCA94720 United States

The impact of bentonite on the corrosion of oxygen-free copper (OF-Cu) and oxygen-free phosphorous copper (OFP-Cu) in prototypical groundwater environments (standard reference electrolyte, SRE) simulating the storage of copper High-Level Nuclear Waste (HLNW) cannisters in granitic rock repositories is explored. At low corrosion potentials (-0.1VSCE), bentonite suppresses copper corrosion in SRE through the anion-exclusion effect, with its inhibitory impact intensifying at higher bentonite concentrations. As the corrosion potential rises, bentonite’s enhanced adsorption of metal cations increases the corrosion current. Additionally, bentonite hydrolysis producing silicate ions that accelerates pitting corrosion, culminating in passive film breakdown. This dual mechanism may amplify intergranular corrosion. In environments where bentonite exacerbates corrosion, OFP-Cu demonstrates superior corrosion resistance, though the introduction of phosphorus may influence the acceleration of intergranular corrosion following passivity breakdown. © 2024, The Authors. All rights reserved.

关键词： Bentonite

Slug flow Characteristics in Inclined and Vertical Channels

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Fluid Dynamics & Materials Processing 2019年第5期15卷 583-595页

作者： Zhihui Wang Wei Luo Ruiquan Liao Xiangwei Xie Fuwei Han Hongying Wang Petroleum Engineering Institute of Yangtze University WuhanChina Laboratory of Multiphase Pipe Flow Gas Lift Innovation CenterChina National Petroleum CorpWuhanChina The Branch of Key Laboratory of CNPC for Oil and Gas Production Yangtze UniversityJingzhouChina Exploration Department of Petro China Tarim Oilfield Company KorlaChina The Third Drilling Company of Bohai Drilling Engineering Co. Ltd.of CNPCTianjinChina Research and Development Center Tuha Oilfield CompanyCNPCTulufanChina

Horizontal well production technology gradually occupies a dominant position in the petroleum *** the rise in water production in the later stage of exploitation,slug flow phenomena will exist in horizontal,inclined and even vertical sections of gas *** grasp the flow law of slug flow and guide engineering practice,the flow law of slug flow at various inclination angles(30°~90°)is studied by means of the combination of laboratory experiments(including high frequency pressure data acquisition system)and finite element numerical *** results reveal that because of the delay of pressure variation at the corresponding position of pipeline resulting from gas expansion,the highest point of pressure change curve corresponds not to the highest point of liquid holdup curve(pressure change lags behind 0.125 s of liquid holdup change).Thus,the delay of pressure should be highlighted in predicting slug flow using pressure parameter change;otherwise the accuracy of prediction will be affected when slug flow *** is generally known that liquid holdup and pressure drop are the major factors affecting the pressure variation and stable operation of ***,the results of finite element numerical simulation and Beggs-Brill model calculation are compared with those of laboratory *** numerical simulation method is applicable to predicting the pressure drop of the pipeline,while the Beggs-Brill model is more suitable for predicting the liquid holdup variation of the *** research conclusion helps reveal the slug flow law,and it is of a scientific guiding implication to the prediction method of flow parameters under slug flow pattern in the process of gas well exploitation.

关键词： Slug flow volume liquid holdup pressure pressure drop flow pattern numerical simulation

Pani Grafted Onto Waste Poros Polyurethane for Co-Adsorption of Multiple Pollutants in Industrial Wastewater

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SSRN 2023年

作者： Wang, Ning Guo, Yirui Song, Yi Yan, Wei Gong, Xuesong Li, Yunfeng Mu, Ruihua Liu, Yonghong Zhang, Luohong School of Environmental and Chemical Engineering Xi'an Polytechnic University Xi'An710048 China Department of Environmental Science and Engineering State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'An710049 China

Up-taking the pollutants simultaneously from industrial wastewater is an urgent in the advanced treatment. In this work, the polyaniline (PANI)-based efficient adsorbent supported by the waste polyurethane(PU) was designed for synchronous adsorption of pollutants (acid red G (ARG), methylene blue (MB), hexavalent chromium Cr(VI), phosphorus (TP), NH4+-N (ammonia nitrogen), NO3-N (nitrate nitrogen) and COD (chemical oxygen demand)). The results showed that the synchronous removal efficiency of ARG, MB, Cr(VI), TP, NH4+-N, NO3-N and COD in simulated wastewater reached 88%, 40%, 90%, 58%, 42%, 30% and 63%, respectively. The adsorption lasted for 1800 min (144 columns) before saturation, and no significant decrease was observed after 5 cycles of regeneration. Combined with the XPS (X-ray photoelectron spectroscopy) and EEM (excitation-emission matrix spectroscopy) analysis, ARG, Cr(VI), NO3-N and TP competed for the same adsorption sites, and the adsorption affinity order was ARG>Cr(Ⅵ)>TP>NO3-. During the adsorption process, Cr(VI) and =N- in PANI chain underwent redox reaction to form Cr(III) and -NH+-, which further promoted the adsorption of anionic pollutants, like H2PO4-. Redox reactions also occurred between Cr(VI) and MB before adsorption forming Cr(III) and small organic fragments. These conclusions prove the feasibility and effectiveness of PU-P/T as a potential engineering adsorbent for co-adsorption of a variety of pollutants. © 2023, The Authors. All rights reserved.

关键词： Adsorption

Influence of Bentonite on Copper Corrosion in Simulated Repository Electrolyte

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SSRN 2024年

The impact of bentonite on the corrosion of oxygen-free copper (OF-Cu) and oxygen-free phosphorous copper (OFP-Cu) in prototypical groundwater environments (standard reference electrolyte, SRE) simulating the storage of copper High-Level Nuclear Waste (HLNW) cannisters in granitic rock repositories is explored. At low corrosion potentials (-0.1V), bentonite suppresses copper corrosion in SRE through the anion-exclusion effect, with its inhibitory impact intensifying at higher bentonite concentrations. As the corrosion potential rises, particularly beyond the "bell-shaped" region in the polarization curve, bentonite's enhanced adsorption of metal cations increases the corrosion current. Additionally, bentonite hydrolysis producing silicate ions that accelerates pitting corrosion, culminating in passive film breakdown. This dual mechanism may amplify intergranular corrosion. In environments where bentonite exacerbates corrosion, OFP-Cu demonstrates superior corrosion resistance, though the introduction of phosphorus may influence the acceleration of intergranular corrosion following passivity breakdown. © 2024, The Authors. All rights reserved.

关键词： Copper corrosion

Effect of Fuel System on the Heat Releasing Method and flow-Path Design of Rocket-Based Combined Cycle Engine

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Effect of Fuel System on the Heat Releasing Method and Flow-...

International Conference on Mechanical and Aerospace engineering (ICMAE)

作者： Xiao Liu Yinhu Wang Yiyan Yang Lei Shi Dekun Yan State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an China Beijing Institute of Long March Vehicle Beijing China Science and Technology on Combustion Internal Flow and Thermal-structure Laboratory Northwestern Polytechnical University Xi’an China

Multi-components rocket-based combined cycle (RBCC) engine is widely applied in most two-stage-to-orbit program due to stable operation performance under variable flight conditions. Present researches numerically compared RBCC’s performance under ramjet mode and scramjet mode, respectively, by using two fuel system, hydrogen and kerosene together with a $\mathrm{k}-\omega$ SST turbulence model. Researches showed that the combustor area ratio should be increased to keep stable pressure difference balance between inflow and flame because of higher caloric value using hydrogen. Distributed heat addition method is benifit for overall performance improvement when using hydrogen. Different from using kerosene, head should be delayedly added in combustor downtream under scramjet mode. Moreover, the advanced heat addition amount should be decreased under ramjet mode to ensure effective isolator operation.

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Solar steam generation enabled by bubbly flow nanofluids

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Solar Energy Materials and Solar Cells 2020年第0期206卷 110292-000页

作者： Yao, Guansheng Xu, Jinliang Liu, Guohua Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization North China Electric Power University Beijing102206 China Key Laboratory of Condition Monitoring and Control for Power Plant Equipment of Ministry of Education North China Electric Power University Beijing102206 China

Plasmonic nanofluids are recently explored to promote steam generation, showing great promise of such fluids for solar thermal applications. However, plasmonic nanoparticles are opaque and the nanofluids require high mass concentration to achieve efficient evaporation, which in turn leads to parasitic light absorption for the underlying particles. In this work, we introduce bubbles into dilute plasmonic nanofluids to enhance solar water evaporation. The dynamic bubbles not only act as light scattering centers to extend the incident light pathway and amplify solar flux, but also provide large gas-liquid interfaces for moisture capture as well as kinetic energy from bubble bursting to improve vapor diffusion. The coupling effect between plasmonic heating and bubbly-flow humidification results in a steam generation rate of 0.72 kg m−2 h−1 under two-sun, which is about three-time higher than that of the pure water. A series of experiments under different light intensities, concentration of nanofluids, gas flow rates as well as photothermal materials such as carbon nanotubes (CNTs) and magnetic Fe3O4 nanoparticles are also conducted to verify the concept. It is concluded that all the nanofluids enhance the steam generation process, and the bubbly flow nanofluids can be further improved the performance. This work provides an original insight on the bubbly flow nanofluids for solar vapor generation, and stands for a basis to design scalable solar evaporators from accessible raw materials. © 2019

关键词： Solar energy

Energy Conversion in the Nanochannel Coupled with Surface Charge and Slip Effect

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SSRN 2022年

作者： Liu, Zheng Feng, Yijun Wang, Lin Liu, Qingyuan Liu, Guohua Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization North China Electric Power University Beijing102206 China

Inspired by the universal phenomena in nature and advances in nanotechnology, the ion transport in nanochannel receives increasing attention and shows great promising in energy conversion. The precedent studies generally predicted the ion transport by tuning the single physical parameter, the understanding of ion dynamics in the real multi-physical coupling systems is still scarce. Here, an ion transport model coupled with surface charge and slip effect is proposed to investigate the energy conversion behavior in nanochannel. The results show that the surface charge density increases with the increasing bulk concentration and nanochannel size. The original boundary slip tends to decrease the surface charge density and the surface charge in turn reduces the boundary slip significantly, which manifests the strong coupling effect of diverse factors. The output power and energy conversion efficiency increases first and then decrease with the increasing bulk concentration. The increase of channel size is beneficial for promoting output power, but unfavorable on energy conversion efficiency. More important, the boundary slip greatly enhances the output power and energy conversion efficiency, leading to a maximum output power and energy conversion efficiency is 2.7 pW and 30%, respectively. As a proof of concept, this work shows the distinct deviation in power generation in ion nanochannel with the constant and dependent physical property, providing the useful information to guide the design of real fluidic energy devices © 2022, The Authors. All rights reserved.

关键词： Ions

Exploring Comprehensive Properties of a Novel Shape-Stabilized Composite Phase Change Material Of Lauric Acid-Palmitic Acid- Tetradecyl Alcohol/Vitrified Beads for Thermal Energy Storage

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SSRN 2024年

作者： Yan, Qiuhui Jia, Mengyu Luo, Jieren Meng, Zeyu School of Building Services Science and Engineering Xi’an University of Architecture and Technology Xi’an710055 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China

Excellent thermal properties are the cornerstone of phase change materials (PCMs) employed for energy storage, and leakage prevention and sufficient strength are the key problems that must be solved in the practical application process of PCMs. Therefore, the advantages of ternary PCMs (Lauric Acid-Palmitic Acid-Tetradecyl Alcohol, LA-PA-TA) and adsorbent carriers (Vitrified Bead, VB) are integrated to obtain a novel LA-PA-TA/VB composite PCM which exhibits favorable phase change temperature (20.1°C-20.5°C) and excellent subcooling (0.4°C). Then, the novel LA-PA-TA/VB is encapsulated with five materials to form shape-stabilized PCMs to reduce leakage. The experiments show that a shape-stabilized LA-PA-TA/VB (SS-LA-PA-TA/VB) encapsulated with the real stone paint emulsion-cement powder presents the optimal packaging effect, namely superior stability and reliability with low mass loss ratio of only 2.67% after 50 times phase change cycles. Next, the SS-LA-PA-TA/VB of the optimal package is further made into thermal energy storage mortar (TESM) with different SS-LA-PA-TA/VB content. It is shown that the thermal properties of TESM increase and the mechanical properties decrease with LA-PA-TA/VB. However, even with the LA-PA-TA up to 30% (30TESM), the compressive strength, flexural strength, apparent density, water absorption, and softening coefficient of the TESM still meets the Chinese National Standard, and some microscopic mechanisms have been investigated. Lastly, temperature regular ability and heat insulation performance of 30TESM and reference mortar are compared by temperature probe embedded inside the mortar blocks and installed in experiential small room. The results present that internal temperature of the mortar blocks, backside and central temperature of small room are 5.4°C, 5.6°C and 2.1°C lower than that of the reference group, respectively. It is thus clear that the novel low cost TESM exhibits a good temperature damping effect and temperature control p

关键词： Phase change materials