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18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2019

作者： Sun, Rulei Zhang, D.L. Zhou, Jiancheng Song, Gongle Tian, Wenxi Qiu, Suizheng Su, G.H. Shaanxi Key Lab. of Advanced Nuclear Energy and Technology Xi'an Jiaotong University Xi'an710049 China School of Nuclear Science and Technology State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University No. 28 Xianning West Road Xi'an China

The state-of-the-art studies on single-phase flow and hear transfer in narrow rectangular channels shows some difference with the conventional theory. In this paper, the experimental study of vertical upward flow resistance of single-phase water in rectangular channels is carried out under isothermal and non-isothermal conditions. The purpose of this study is to reveal the flow resistance of narrow rectangular channels and focus on the effect of transverse non-uniform heating. The geometric dimensions of the test section are as follows: depth 2.0 mm, aspect ratio 30. The experimental results show that the friction coefficient of rectangular narrow channel under isothermal condition is obviously larger than that of conventional channels, and the transition zone is 2600 © 2019 American Nuclear Society. All rights reserved.

关键词： Aspect ratio

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Impact on mechanical robustness of water droplet due to hydrophilic nanoparticles

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PHYSICS OF FLUIDS 2020年第12期32卷 122110-122110页

作者： Zhou, Jiandong Wang, Xin Su, Jinzhan Jing, Dengwei Mohamad, A. A. Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China Univ Calgary Schulich Sch Engn Dept Mech & Mfg Engn CEERE Calgary AB T2N 1N4 Canada

The mechanical robustness of droplets is a crucial factor for many applications. In the present work, we reported that adding a small and certain number of hydrophilic nanoparticles can significantly enhance the mechanical robustness of water droplets. Among the various hydrophilic nanoparticles investigated, SiO2 was found to be the most effective one. Experiments and molecular dynamics simulations were used to understand the physics of the phenomenon. It turned out that the microscopic structure at the solid-liquid interface becomes more ordered compared to the pure liquid droplet due to the interaction between nanoparticles and liquid molecules. This ordered structure can strengthen the solvent-mediated forces between nanoparticles, which, in turn, enhances the solid-like performance of the liquid surface and thus the robustness of the droplet.

关键词： Nanoparticles

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Visible-light photoredox-catalyzed C-O bond cleavage of diaryl ethers by acridinium photocatalysts at room temperature

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NATURE COMMUNICATIONS 2020年第1期11卷 6126-6126页

作者： Tan, Fang-Fang He, Xiao-Ya Tian, Wan-Fa Li, Yang Xi An Jiao Tong Univ Frontier Inst Sci & Technol Xian 710054 Shaanxi Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710054 Shaanxi Peoples R China Nankai Univ State Key Lab Elementoorgan Chem Tianjin 300071 Peoples R China

Cleavage of C-O bonds in lignin can afford the renewable aryl sources for fine chemicals. However, the high bond energies of these C-O bonds, especially the 4-O-5-type diaryl ether C-O bonds (similar to 314 kJ/mol) make the cleavage very challenging. Here, we report visible-light photoredox-catalyzed C-O bond cleavage of diaryl ethers by an acidolysis with an aryl carboxylic acid and a following one-pot hydrolysis. Two molecules of phenols are obtained from one molecule of diaryl ether at room temperature. The aryl carboxylic acid used for the acidolysis can be recovered. The key to success of the acidolysis is merging visible-light photoredox catalysis using an acridinium photocatalyst and Lewis acid catalysis using Cu (TMHD)(2). Preliminary mechanistic studies indicate that the catalytic cycle occurs via a rare selective electrophilic attack of the generated aryl carboxylic radical on the electron-rich aryl ring of the diphenyl ether. This transformation is applied to a gram-scale reaction and the model of 4-O-5 lignin linkages.

关键词： Photocatalysis Sustainability Synthetic chemistry methodology

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Activated overall water splitting over a Ni-Fe layered double hydroxide electrocatalyst by V doping and sulfuration

APPLICATIONS IN ENERGY AND COMBUSTION SCIENCE

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APPLICATIONS IN ENERGY AND COMBUSTION SCIENCE 2023年 14卷

作者： Wu, Wentong Peng, Lei Min, Boya Huang, Jie Liu, Saiya Lu, Kejian Lu, Shijian Jing, Dengwei Zheng, Mingsheng Liu, Maochang Xi An Jiao Tong Univ Int Res Ctr Renewable Energy State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China 8 Oil Prod Plant PetroChina Changqing Oilfield Co Xian 710016 Shaanxi Peoples R China China Univ Min & Technol Carbon Neutral Inst Xuzhou 221008 Jiangsu Peoples R China Gree Altairnano New Energy Inc Zhuhai 519040 Peoples R China Univ Sci & Technol Beijing Sch Chem & Biol Engn Beijing 100083 Peoples R China

Ni-Fe layered double hydroxide (NiFe-LDH) is regarded as one of the promising non-noble electrocatalyst. However, the limited number of active sites and poor electrical conductivity impede its further development. Herein, we report the synthesis of a Ni foam supported NiFe-LDH electrocatalyst modified by V doping and sulfuration (NiFeV-S/NF). This modification endows the catalyst excellent property toward hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and overall water splitting. Only 211 mV and 127 mV of the overpotentials are required to achieve the current density of 10 mA cm-2 for OER and HER in 1 M KOH electrolyte, respectively. Particularly, the prepared NiFeV-S/NF could serve as a bifunctional electrocatalyst for overall water splitting, with a cell voltage of 1.573 V to reach a current density of 10 mA cm-2. In principle, the success relies on the intrinsically improved conductivity, increased specific surface area and the number of active sites, as well as the heterojunction structure of the catalyst. Therefore, this work provides a new idea for the design and preparation of more efficient noble-metal-free bifunctional electrocatalysts.

关键词： NiFe-LDH Non -noble electrocatalyst Ternary transition metal sulfide V doping Sulfuration

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A comprehensive experimental investigation on the PFI spray impingement: Effect of impingement geometry, cross-flow and wall temperature

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APPLIED THERMAL engineering 2019年 159卷 113848-000页

作者： Li, Yaoting Huang, Yongcheng Yang, Shangsheng Luo, Kun Chen, Rixin Tang, Chenglong Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Sch Energy & Power Engn Xian 710049 Shaanxi Peoples R China

In this work, an experimental study on the effects of the impingement geometry, the cross-flow intensity and the wall temperature on the characteristics of an impinging port fuel injection (PFI) spray was conducted. The transient development of the impinging spray was recorded by a high-speed camera with Mie scattering. Based on the high-speed images, the spray tip penetration (S) and the impinged spray height (H-w) were obtained. The results show that with the increase of the impingement distance (L-w), S increases and H-w decreases at the same time after the impingement. As the impingement angle (theta(w)) increases, S decreases while H-w first increases and then decreases. With the increase of the cross-flow velocity (U-c), less part of the spray impinges onto the wall, and S significantly increases. As the wall temperature (T-w) rises, S does not show much variation. However, H-w increases gently for T-w lower than 420 K, and it increases sharply for T-w higher than 420 K due to the Leidenfrost mechanism. The effects of the above factors (L-w, theta(w), U-c, T-w) on S and H-w were finally evaluated and compared through the introduction of a contribution index.

关键词： Port fuel injection Spray impingement Cross-flow Wall temperature Spray tip penetration Impinged spray height

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Nanoparticle-induced ion-sensitive reduction in decane-water interfacial tension

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PHYSICAL CHEMISTRY CHEMICAL PHYSICS 2018年第35期20卷 22796-22804页

作者： Wen, Boyao Sun, Chengzhen Bai, Bofeng Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China

The synergistic effect of ions and nanoparticles on the interfacial tension is of great significance for extensive applications in interface-related industrial processes. However, its mechanisms are still unclear owing to a lack of understanding on the interaction between nanoparticles/ions at the interface. Here, we employ the molecular dynamics method to explore the synergistic effect of ions and nanoparticles on reducing the decane-water interfacial tension and reveal the dominant role of the three-phase contact angle and the interaction between nanoparticles. The results show that the reduction of interfacial tension is sensitive to cation species and temperature. The stronger hydration of cations induces an increased three-phase contact angle, weakening the interaction between nanoparticles and water molecules at the interface. Hence, the virial term of interfacial tension decreases. Meanwhile, the potential of mean force between nanoparticles at the interface indicates that the order of interaction strength between nanoparticles for different cations is Ca2+ > Mg2+ > Na+. The strong interaction between nanoparticles restricts the motion of nanoparticles and water molecules at the interface, inducing a reduced kinetic energy term of interfacial tension. Therefore, the interfacial tension decreases after adding the nanoparticles. Besides, as temperature rises, the difference in the adsorption ability of nanoparticles on water molecules causes a falling interfacial tension with a characteristic stage.

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Noble-metal-free MOF derived hollow CdS/TiO2 decorated with NiS cocatalyst for efficient photocatalytic hydrogen evolution

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APPLIED SURFACE SCIENCE 2019年 476卷 378-386页

作者： Li, Naixu Huang, Hailu Bibi, Rehana Shen, Quanhao Ngulube, Richard Zhou, Jiancheng Liu, Maochang Southeast Univ Sch Chem & Chem Engn Nanjing 211189 Jiangsu Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Int Res Ctr Renewable Energy Xian 710049 Shaanxi Peoples R China Jiangsu Key Lab Biomass Energy & Mat Nanjing 210042 Jiangsu Peoples R China Southeast Univ Jiangsu Prov Hitech Key Lab Biomed Res Nanjing 211189 Jiangsu Peoples R China

Noble-metal-free hollow NiS/CdS/TiO2 (NS/CT) nanohybrid photocatalyst was prepared by a facile hydrolysis combining sulfidation process using metal-organic framework (MOF) as a template. The as-prepared composites were characterized by SEM, TEM, XRD, XPS, UV-vis, and photoelectrochemical techniques. It is found that NS/CT composites with porous hollow structure show significantly enhanced photocatalytic efficiency compare to TiO2, or CdS/TiO2, or even Pt decorated CdS/TiO2 photocatalysts, for hydrogen evolution from water upon visible light irradiation. Significantly, NS/CT composite with optimum amount of 30% CdS and 0.3% NiS exhibits the highest photoactivity, with H-2 production rate of 2149.15 mu mol.g(-l).h(-1), which is 23.9 and 2.3 times higher than that of the pure CdS particles and the CdS/TiO2 nanocomposites, respectively. The superiority of the composites arises from the synergistic effect of the heterojunction for rapid charge separation and the NiS cocatalyst for accelerated surface redox reaction.

关键词： CdS/h-TiO2 NiS cocatalyst Heterojunction H-2 production Photocatalysis

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A comprehensive review of the leak flow through micro -cracks (in LBB) for nuclear system: Morphologies and thermal -hydraulic characteristics

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NUCLEAR engineering AND DESIGN 2020年 362卷 110537-110537页

作者： Zhang, J. Wang, M. J. Zhang, Z. Sun, H. Wu, Y. W. Tian, W. X. Qiu, S. Z. Su, G. H. Xi An Jiao Tong Univ Shaanxi Key Lab Adv Nucl Energy & Technol Xian 710049 Peoples R China Xi An Jiao Tong Univ Dept Nucl Sci & Technol State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China Suzhou Nucl Power Res Inst Co Ltd Nucl Safety & Operat Engn Ctr Shenzhen 518000 Peoples R China

Piping cracks are widely spread in the nuclear system, which affects the safety and economy of reactors. The leak before break (LBB) concept detects the leakage through cracks and afterwards takes human intervention, to avoid break and rupture of pipes. Therefore the leakage through crack determines the safety of the reactor second pressure boundary. This paper looks over the existing research on LBB application and focuses on the leak through crack, which largely depends on the crack morphologies and thermal–hydraulic characteristics. The present work categories the cracks in nuclear piping system, where various morphologies are concluded for different cracks. The thermal–hydraulic characteristics of the leak flow through cracks, such as flow resistance, critical flow, thermodynamic non-equilibrium and flow pattern were systematically summarized and reviewed. Besides, the leak experiments were collected for natural and artificial cracks, and the theoretical calculation methods including commercial system software, numerical simulation and interdisciplinary approaches were evaluated. At last, the existing research on the leak flow through crack was summed up and the inherent relationship were clarified. This review paper provides a comprehensive foundation and guidance for the mechanism understanding of leak flow through cracks and LBB application.

关键词： Leak flow Micro-crack Leak before break (LBB) morphologies Thermal-hydraulic

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Current density effects on plasma emission during plasma electrolytic oxidation (PEO) on AZ91D-magnesium alloy

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MODERN PHYSICS LETTERS B 2020年第7-9期34卷

作者： Girase, Krunal Wang, Zhenzhen Kamimoto, Takahiro Deguchi, Yoshihiro Jeon, Mingyu Cui, Minchao Chou, Chen-Chia Huang, Eddy Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn 28 Xianning West Rd Xian 710049 Shaanxi Peoples R China Tokushima Univ Grad Sch Adv Technol & Sci 2-1 Minamijosanjima Cho Tokushima 7708506 Japan Korea Maritime & Ocean Univ Div Mech Engn 727 Taejong Ro Busan 49112 South Korea Northwestern Polytech Univ Key Lab High Performance Mfg Aero Engine MIIT 127 West Youyi Rd Xian 710072 Shaanxi Peoples R China Natl Taiwan Univ Sci & Technol Dept Mech Engn 43Sec 4Keelung Rd Taipei 10607 Taiwan

The effect of bipolar pulse mode current ratio (anodic to cathodic) on plasma emission behavior was investigated in Plasma Electrolytic Oxidation (PEO) on AZ91D Mg-Alloy. Two cases of current ratio as 1.20 and 0.88 were applied to the sample. Plasma emission behavior was studied using plasma images and plasma emission measured by photodetector and Intensified Charged-Couple Device (ICCD) camera. The current ratio of greater than 1 shows the continuous increase and then stabilization in emission intensity with a gradual increase in voltage throughout the PEO process. In contrast, the current ratio of less than 1, a sudden drop in plasma emission intensity with voltage was found after 786 s. Therefore, PEO process can be divided into two regimes, arc regime and soft regime, before and after voltage drop, respectively. Results of measured spectra show that a soft regime does not have atomic or ionic excitation during PEO process. It is demonstrated that the growth of porous layer during PEO can be controlled, which is benefit for the protective oxide coating of sample.

关键词： Plasma electrolytic oxidation (PEO) AZ91D Mg-alloy arc regime soft regime

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Numerical Investigation on the Two Phase flow Behaviors in Supercritical Water Fluidized Bed with Swirling flow Distributor

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HEAT TRANSFER engineering 2018年第17-18期39卷 1593-1604页

作者： Jin, Hui Wu, Zhenqun Guo, Liejin Su, Xiaohui Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xianning West Rd Xian 710049 Shaanxi Peoples R China

Supercritical water fluidized bed reactor is a promising in the clean and efficient conversion of coal, and the distributor is one of the key component for the heat and mass transfer enhancement. However, the optimization study for the distributor in supercritical water fluidized bed reactor has been seldom conducted due to the special thermal properties of supercritical water. In this work, the swirling flow distributor was designed for its optimization for heat and mass transfer inside a supercritical water fluidized bed reactor. The swirling flow can be generated by the concentric circle or triangle type hole distribution in distributor with 0 or 45 degrees intersection angle between the fluid inlet velocity direction and the distributor plane. The computational particle fluid dynamics (SCWFB) method, which has quick calculating speed and high accuracy, was used in this work to study the particle-fluid two-phase flow behaviors inside SCWFB with swirling flow distributors. Investigations were made to reveal the influence of the hole distribution type and intersection angle on the bed pressure drop and particle volume fraction characteristics. The results showed that the triangle type distributor with 45 degrees intersection angle has the best fluidization performance. The conclusions drawn may has potential application for continuous and stable operation of supercritical water fluidized bed reactor for coal gasification.

关键词： Fluidized beds

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