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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 (-0.1V), 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

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

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

Effect of Surface Charge Gradient on the Concentration Difference Driven Energy Conversion in Nanochannel

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SSRN 2022年

作者： Liu, Zheng 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

There has been increasing interest in the concentration gradient power generation due to its facile availability in nature. However, the effect of surface charge gradient on the ions transport and energy conversion has not been fully studied so far. Herein, this work proposed nanofluid systems to show how the surface charge gradient influences the energy conversion behavior in nanochannel. The results show that the positive surface charge gradient (PSCG) and negative surface charge gradient (NSCG) all improve the energy conversion performance in contrast to homogeneous surface charge (HSC) condition. The NSCG case exhibits the distinguish performance with the maximum output power and energy conversion efficiency of 1.2 pW and 49%, respectively. Such high performance mainly arises from its excellent ion selectivity during the energy conversion. For practical application, the output voltage of long nanochannel with NSCG condition almost maintains constant and the resistance decreases gradually when the high surface charge is fixed and tuning the low surface charge, which can be regarded as a steady voltage resource. These results provide a general strategy for tuning nanofluid power generation and are beneficial to understand the basic mechanism in fluidic energy device. © 2022, The Authors. All rights reserved.

关键词： Energy conversion efficiency

Assessment on the Long Term Performance of a LaNi 5 based Hydrogen Storage System

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Energy Procedia 2012年 29卷 720-730页

作者： Fusheng Yang Xinxin Cao Zaoxiao Zhang Zewei Bao Zhen Wu Nyallang Nyamsi Serge State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 P. R.China Suzhou Research Institute Xi’an Jiaotong University Suzhou 215123 P. R. China

Metal hydride represents a promising candidate for hydrogen storage, because the technique is essentially safe, compact and flexible. However, the properties of the metal hydride tend to change in repeated hydriding/dehydriding cycles, which will inevitably affect the performance of corresponding hydrogen storage system. The effect is investigated in this paper by numerical simulation using a commercial package COMSOL MULTIPHYSICS 3.5a, and a typical material- LaNi5 is chosen for discussion. Through sensitivity analysis, the influences of variation in key properties over repeated cycles on the charging time of a tank-type storage system, are evaluated and some useful conclusions are drawn.

关键词： Metal hydride Hydrogen storage system Hydriding/dehydriding cycles Charging time Reaction kinetics

Improvement on Quantitative Measurement of Fly Ash Contents Using Laser-Induced Breakdown Spectroscopy

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Journal of flow Control, Measurement & Visualization 2015年第1期3卷 10-21页

作者： Zhenzhen Wang Yoshihiro Deguchi Hiroaki Watanabe Ryoichi Kurose Junjie Yan Jiping Liu State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an China Graduate School of Advanced Technology and Science The University of Tokushima Tokushima Japan Energy Engineering Research Laboratory The Central Research Institute of Electric Power Industry Kanagawa Japan Department of Mechanical Engineering and Science Advanced Research Institute of Fluid Science and Engineering Kyoto University Kyoto Japan

Contents of fly ash are important factors for the operation of coal-fired plants. Real-time monitoring of coal and fly ash such as unburned carbon in fly ash can be an indicator of the combustion conditions. Because of the strong signal intensity and the relative simplicity of the LIBS (Laser- Induced Breakdown Spectroscopy) technique, LIBS can be applicable for real-time composition measurement of coal and fly ash. This research presented here focused on the clarification of the effects of plasma temperature and coexisting materials on quantitative measurement of fly ash contents. Quantitative capability of LIBS was improved using the proposed plasma temperature correction method. The CO2 effect was also discussed to accurately evaluate unburned carbon in fly ash in exhausts. Using the results shown in this study, quantitative measurement of fly ash contents has been improved for wider applications of LIBS to practical fields.

关键词： Laser-Induced Breakdown Spectroscopy Fly Ash Temperature Correction CO2 Effect

Bionic microchannels for step lifting transpiration

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International Journal of Extreme Manufacturing 2023年第2期5卷 244-252页

作者： Zhaolong Wang Qiu Yin Ziheng Zhan Wenhao Li Mingzhu Xie Huigao Duan Ping Cheng Ce Zhang Yongping Chen Zhichao Dong Interdisciplinary Research Center of Low-carbon Technology and Equipment College of Mechanical and Vehicle EngineeringHunan UniversityChangsha 410082People’s Republic of China MOE Key Laboratory for Power Machinery and Engineering School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Qian Xuesen Laboratory of Space Technology China Academy of Space Technology(CAST)Beijing 100094People’s Republic of China Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application School of Environmental Science and EngineeringSuzhou University of Science and TechnologySuzhouJiangsu 215009People’s Republic of China Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education School of Energy and EnvironmentSoutheast UniversityNanjing 210096People’s Republic of China Chinese Academy of Sciences Key Laboratory of Bio-inspired Materials and Interface Sciences Technical Institute of Physics and ChemistryChinese Academy of Sciences100190 BeijingPeople’s Republic of China

Those various cross-sectional vessels in trees transfer water to as high as 100 meters,but the traditional fabrication methods limit the manufacturing of those vessels,resulting in the non-availability of those bionic ***,we fabricate those bionic microchannels with various cross-sections by employing projection micro-stereolithography(PμSL)based 3D printing *** circumradius of bionic microchannels(pentagonal,square,triangle,and five-pointed star)can be as small as 100μm with precisely fabricated sharp ***'s more,those bionic microchannels demonstrate marvelous microfluidic performance with strong precursor effects enabled by their sharp *** significantly,those special properties of our bionic microchannels enable them outstanding step lifting performance to transport water to tens of millimeters,though the water can only be transported to at most 20 mm for a single bionic *** mimicked transpiration based on the step lifting of water from bionic microchannels is also *** precisely fabricated,low-cost,various cross-sectional bionic microchannels promise applications as microfluidic chips,long-distance unpowered water transportation,step lifting,mimicked transpiration,and so on.

关键词： bionic microchannel microfluidics water transportation step lifting 3D printing