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Experimental investigation of entrainment effect on the countercurrent flow in the Hot Leg and Pressurizer Surge Line assembly of third-generation passive nuclear reactors

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NUCLEAR engineering AND DESIGN 2018年 335卷 326-338页

作者： Yu, Jiangtao Zhang, Dalin Shi, Leitai Tian, Wenxi Su, G. H. Qiu, S. Z. Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn 28 Xianning West Rd Xian 710049 Shaanxi Peoples R China Xi An Jiao Tong Univ Sch Nucl Sci & Technol Shanxi Key Lab Adv Nucl Energy & Technol 28 Xianning West Rd Xian 710049 Shaanxi Peoples R China

The effect of entrainment from the Hot Leg (HL) to the Pressurizer Surge Line (PZR-SL) on the characteristics of Countercurrent flow (CCF), is experimentally studied using air-water in a transparent test section, 1/4 scaled-down model of the HL and PZR-SL assembly of AP1000. The typical CCF behaviors are recorded with video cameras for understanding of mechanisms of Countercurrent flow Limitation (CCFL) affected by entrainment. Two entrainment flow regimes, stratified-flow entrainment and slug-flow entrainment, are found to occur under certain HL pipe water levels and air velocity conditions. The entrainment effect on the characteristics of CCF in the WA section is analyzed in detail based on the two-phase air and water Kutateladze numbers, the transient hydraulic parameters and the flow behaviors. The stratified-flow entrainment does not always influence CCFL extent, unless the entrainment is strong enough and reverse flow of water occurs in the PZR-SL pipe. However, the slug-flow entrainment markedly influences CCFL extent. Two empirical correlations are developed respectively for high HL pipe water level situation with slugging entrainment and for medium and low HL pipe water level situation without slugging entrainment. The present data are compared and verified with the Small-Break Loss-of-Coolant Accidents (SB-LOCAs) tests data on AP600 Scaled Integral Test Facility (APEX). The present experimental research provide insight on the CCF flow phenomena in the HL and PZR-SL assembly for the third-generation passive nuclear reactors during the Fourth Stage Automatic Depressurization Stage (ADS-4) of SBLOCAs and support theoretical model development and the validation of computational codes.

关键词： Third-generation passive nuclear reactors Hot Leg and Pressurizer Surge Line Assembly Countercurrent flow Limitation Entrainment effect Visual air-water experiments

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Effects of Liquid Film Instability on Spray Features of Liquid-Liquid Pintle Injectors

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AIAA JOURNAL 2024年第11期62卷 4247-4264页

作者： Zhao, Fan Zhang, Haibin Zhao, Liang Bai, Bofeng Xi An Jiao Tong Univ Xian 710049 Peoples R China State Key Lab Multiphase Flow Power Engn Xian Peoples R China Sch Chem Engn & Technol State Key Lab Multiphase Flow Power Engn Xian Peoples R China

As one of the crucial structural parameters for the pintle injectors, the design of the skip distance ratio is still heavily empirical-dependent in engineering, and the intrinsic correlations between the skip distance ratio and spray characteristics of liquid-liquid pintle injectors are also unclear. Inspired by the observations that the instability of axial liquid film exerts significant influence on the downstream spray behaviors of a liquid-liquid pintle injector, the influence of the skip distance ratio on the instability of the axial liquid film and the subsequent spray characteristics of the pintle injector was experimentally investigated. The spray steadiness of the pintle injector was evaluated based on the instantaneous images using the proper orthogonal decomposition technique, and the effects of the skip distance ratio and the momentum ratio on the spray features were analyzed. Furthermore, a proactive strategy was proposed to adjust the liquid film instability by modifying the outer wall morphology of the pintle post, and the verification experiments were carried out based on three different wall morphologies. It was discovered that the rough wall enhances the axial liquid film instability and promotes the liquid sheet breakup and atomization of the pintle injector. These results provide new insights and valuable references for the optimization design of pintle injectors.

关键词： Pintle Injector Bipropellants Probability Density Functions Spray Visualization Image Analysis Doublet Impinging Injectors Twin-Fluid Atomization Kelvin-Helmholtz Instability Boundary Layer Instability

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Transient analysis of tritium transport characteristics of thorium molten salt reactor with solid fuel

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ANNALS OF NUCLEAR ENERGY 2020年 141卷 107337-107337页

作者： Wang, Chenglong Qin, Hao Tian, Wenxi Qiu, Suizheng Su, G. H. Xi An Jiao Tong Univ Dept Nucl Sci & Technol Xian 710049 Shaanxi Peoples R China Xi An Jiao Tong Univ Shaanxi Key Lab Adv Nucl Energy & Technol Xian Shaanxi Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian Shaanxi Peoples R China

Tritium management is a vital factor that needs to be considered before a molten salt reactor (MSR) or fluoride-salt-cooled high-temperature reactor (FHR) is constructed. The analysis of tritium transport characteristics under steady and transient conditions is essential in the conceptual design of MSRs and FHRs. In this study, tritium transport characteristics analysis is conducted for a fluoride-salt-cooled pebble bed reactor, i.e., thorium molten salt reactor with solid fuel (TMSR-SF) under accident conditions. The tritium transport characteristics analysis (TAPAS) code is improved with a power model and heat-and-mass transfer model to adapt to TMSR-SF. The transient responses of the tritium transport characteristics of TMSR-SF under the unprotected reactivity insertion accident (URIA) and unprotected overcooling accident (UOC) are determined. It is found that the amount of tritium fluoride (TF) adsorbed on graphite varies, indicating the dynamic equilibrium between the TF adsorption and desorption on graphite. Due to the nuclear density variations of Li-6 and Be-9 in the fluoride salt under the accident conditions, the tritium production rate increases and decreases under the UOC and URIA conditions, respectively. Generally, under these two accident conditions, the tritium permeation rates are lower than that of the normal operation condition. In these cases, it is unnecessary to develop extra safety facilities for tritium control. This study contributes to the tritium management of TMSR-SF. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Tritium transport characteristics Transient conditions TMSR-SF Tritium permeation Graphite adsorption

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MgFe2O4-biochar based lanthanum alginate beads for advanced phosphate removal

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CHEMICAL engineering JOURNAL 2020年 387卷 123305-000页

作者： Wang, Li Wang, Jingyi Yan, Wei He, Chi Shi, Yijing Xi An Jiao Tong Univ Sch Energy & Power Engn State Key Lab Multiphase Flow Power Engn Dept Environm Sci & Engn Xian 710049 Peoples R China South China Normal Univ SCNU Environm Res Inst Guangdong Prov Key Lab Chem Pollut & Environm Saf Guangzhou 510006 Peoples R China South China Normal Univ MOE Key Lab Theoret Chem Environm Guangzhou 510006 Peoples R China

MgFe2O4-biochar based lanthanum alginate beads (MgFe2O4-BM-La(b)) were prepared and used for phosphate removal from aqueous solution. MgFe2O4-BM-La(b) was synthesized via co-precipitation of Fe and Mg ions onto the reed precursor, followed by gelation-calcination method, in which gelation was achieved by in-situ cross-linking of lanthanum alginate. Based on pre-screen adsorption experiments, MgFe2O4-BM-La(b) fabricated under optimal conditions showed the adsorption capacity over 20 times higher than pristine biochar(BC), and about 2.5 times higher than that of beads without the addition of BC or MgFe2O4. MgFe2O4-BM-La(b) exhibited favorable mass transfer performance through kinetic adsorption comparison between powder and bead type adsorbents. Results from characterization of MgFe2O4-BM-La(b) showed the rough morphologies with numerous MgFe2O4 nanoparticles adhered on the BC substrate, endowed the bead with excellent magnetic performance for easy separation. In fixed-bed column runs of synthetic secondary treated wastewater (STWW), MgFe2O4-BM-La (b) showed the treatment volume of similar to 1205 BV when effluent phosphate concentration was below 0.5 mg/L, with the capacity loss of about 30% in three continuous adsorption-regeneration cycles. These results illustrated the synergistic effect of MgFe2O4, La2O3 and BC during phosphate adsorption in practical application. The comparison of FTIR and XPS analyses revealed that through protonation between surface hydroxyl groups and H+, the phosphate adsorption of MgFe2O4-BM-La(b) was dominated by specific forces ligand exchange and inner-sphere complexation, followed by electrostatic attraction. The superiorities of magnetic bead adsorbent with preferable adsorption capacity and mass transfer performance suggested that MgFe2O4-BM-La(b) can serve as a promising filling adsorbent for phosphate removal in industrial application.

关键词： MgFe2O4 Biochar beads Lanthanum alginate Phosphate adsorption

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Experimental investigations on flow characteristics of two parallel channels in a forced circulation loop with supercritical water

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APPLIED THERMAL engineering 2016年 106卷 98-108页

作者： Zhang, Lei Cai, Benan Weng, Yu Gu, Hongfang Wang, Haijun Li, Hongzhi Chatoorgoon, Vijay Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China Univ Manitoba Dept Mech Engn Winnipeg MB R3T 5V6 Canada Xian Thermal Power Res Inst Co Ltd Xian 710032 Peoples R China

The instability of supercritical water flow inside two parallel channels is investigated experimentally in this paper. Two types of instabilities with various oscillation periods occur at different power region during the heating process, indicating the existence of two types of dynamic instabilities. The type I instability occurs when the outlet temperature of the test section surpasses the pseudo-critical temperature. Sudden increase of the pressure drop cause a big disturbance to the system which results in a periodic feedback between the pressure drop and the mass flow rate. Large oscillations were found in the entire system at low heating power during which the two parallel channels oscillates in phase with the whole system with a long oscillation period (20-300 s). The type II instability occurs only in the heated section at high powers at which the two parallel channels oscillate 180 out of phase while the rest of the system is stable. The period of type II instability is relatively small, i.e. 2-5 s. With Ambrosini's non-dimensional parameters, a stability map was generated using the obtained instability data. Analysis of the instability map showed the expected result that no instability occurs when the exit fluid temperature is below the pseudo-critical temperature regardless of the system pressure, inlet temperature, heating power, and local loss coefficient. The influences of inlet mass flow rate, inlet fluid temperature and system pressure on instabilities were also studied. (C) 2016 Elsevier Ltd. All rights reserved.

关键词： Parallel channels Supercritical water Density wave oscillation Forced circulation

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A mechanism of heat transfer enhancement or deterioration of nanofluid flow boiling

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INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER 2020年 158卷 119985-119985页

作者： Wang, Yun Deng, Kuanghan Wu, Junmei Su, Guanghui Qiu, Suizheng Nucl Power Inst China CNNC Key Lab Nucl Reactor Thermal Hydraul Technol 328 Changshun Ave Chengdu 610213 Peoples R China Xi An Jiao Tong Univ State Key Lab Strength & Vibrat Mech Struct Xianning West Rd 28 Xian 710049 Peoples R China Xi An Jiao Tong Univ Sch Nucl Sci & Technol State Key Lab Multiphase Flow Power Engn Xianning West Rd 28 Xian 710049 Peoples R China

In present work, the heat transfer characteristics of SiC/H2O and Graphite/H2O nanofluids flow boiling are experimentally studied with the consideration of pressure, mass flux and heat flux. Compared with based fluid, both enhancement and deterioration of nanofluids boiling heat transfer are found. The flow boiling heat transfer capacities of 0.1vol.% SiC/H2O nanofluid is changed from -24.7% to 30.6% compared with deionized water. Instead, it is changed from -29.4% to 13.3% for 0.1vol.% Graphite/H2O nanofluid. In addition, a mechanism of this phenomenon from the point of view of the assistance and resistance. The assistance includes the improving of the thermal physical properties, the decreasing of surface tension and latent heat, the decreasing of contact angle, decreasing of the surface energy. Instead, the resistance is mainly the decreasing of the number of boiling site. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Nanofluid flow boiling heat transfer Enhancement or deterioration Mechanism

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The effects of oxide supports on the low temperature hydrogenation activity of acetone over Pt/Ni bimetallic catalysts on SiO₂, γ-Al₂O₃ and TiO₂

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APPLIED CATALYSIS A-GENERAL 2011年第1-2期393卷 44-49页

作者： Qi, Suitao Cheney, Beth A. Zheng, Renyang Lonergan, William W. Yu, Weiting Chen, Jingguang G. Univ Delaware Dept Chem Engn Ctr Catalyt Sci & Technol Newark DE 19716 USA Xi An Jiao Tong Univ Sch Energy & Power Engn Dept Chem Engn State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China Peking Univ Coll Chem & Mol Engn Beijing Natl Lab Mol Sci State Key Lab Struct Chem Unstable & Stable Speci Beijing 100871 Peoples R China

Low temperature (308K) hydrogenation of acetone was used as a probe reaction to investigate the support effect on the hydrogenation activity of Pt/Ni bimetallic catalysts supported on TiO2, SiO2 and gamma-Al2O3. The oxide supports significantly affected the catalytic properties of Pt/Ni catalysts, in which Pt/Ni/SiO2 bimetallic catalysts exhibited significantly higher activity than the other two bimetallic catalysts. TEM measurements revealed that the three supported Pt/Ni bimetallic catalysts have similar particle size distribution, while CO chemisorption measurements showed very different chemisorption capacity. Extended X-Ray absorption fine structure (EXAFS) measurements of the Pt L-III-edge indicated that Pt atoms were fully reduced and the Pt-Ni bimetallic bonds were formed on all three catalysts. The extent of Pt-Ni bond formation followed the trend of SiO2 > gamma-Al2O3 > TiO2, which correlated very well with the hydrogenation activity. (c) 2010 Elsevier B.V. All rights reserved.

关键词： Support effect Pt/Ni bimetallic catalysts Hydrogenation Acetone EXAFS

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Electricity mediated plasmonic tip engineering on single Ag nanowire for SERS

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OPTICS EXPRESS 2018年第19期26卷 25031-25036页

作者： Dai, Han Fu, Pengfei Li, Zhutie Zhao, Junfeng Yu, Xinxiang Sun, Jie Fang, Hongjie Yantai Nanshan Univ Lab Adv Light Alloy Mat & Devices Longkou 265713 Peoples R China Hang Xin Mat Technol Co Ltd Longkou 264006 Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China

An electricity-mediated plasmonic engineering was applied on a single Ag nanowire to engineer its tip for surface-enhanced Raman scattering (SERS). Under this constant photoelectric field treatment. a significant sharpening of the tip and reduction of the surface fluctuation was observed for the Ag nanowire tip via in situ atomic force microscopy. A significant SERS signal enhancement was thus obtained after the tip engineering. The relevant dynamic mechanisms of the tip engineering, including the light-induced plasmonic phase transition and electrostatic force driven flow on the Ag nanowire tip are discussed in detail. It is expected that this type of tip engineering will greatly enhance the signal of single metal nanowire SERS probes and provide new insights into fabrication technologies for metal nanostructures. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： Electric fields Light fields Light wavelength Optical microscopy Scanning electron microscopy Surface enhanced Raman scattering

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Recent developments of nanoparticles additives to the consumables liquids in internal combustion engines: Part I: Nano-fuels

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JOURNAL OF MOLECULAR LIQUIDS 2020年 318卷 114250-114250页

作者： Hatami, Mohammad Hasanpour, Maryam Jing, Dengwei Esfarayen Univ Technol Dept Mech Engn Esfarayen North Khorasan Iran Xi An Jiao Tong Univ Int Res Ctr Renewable Energy State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China Univ Tehran Dept Chem Engn Tehran Iran

The main objective of this review study is investigation of the nanofluids application in internal combustion engines. For this aim, three main sections about using consumable nanofluids in engines (i.e. fuel, lubricant and coolant) are considered to collect both numerical and experimental studies. In this part of review, nano-fuels are introduced which their base fuel can be diesel, bio-diesel, gasoline, alcoholic or blended fuels. By a complete review, effects of these nano-fuels on the engine performance, BSFC, exhaust emissions are discussed and finally the most efficient nano-fuels are introduced form the exhaust emission reduction, BSFC reduction or engines efficiency improvements viewpoints. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Nano-fuel Internal combustion engine Bio-diesel Exhaust emission BSFC

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Insight into the Synergistic Effect on Selective Adsorption for Heavy Metal Ions by a Polypyrrole/TiO₂ Composite

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LANGMUIR 2018年第34期34卷 10187-10196页

作者： Chen, Jie Yu, Mengting Wang, Caiyun Feng, Jiangtao Yan, Wei Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Dept Environm Sci & Engn Xian 710049 Shaanxi Peoples R China Univ Wollongong AIIM Facil Intelligent Polymer Res Inst ARC Ctr Excellence Electromat Sci North Wollongong NSW 2500 Australia

Polymer/metal oxide composites are promising candidates for the treatment of water pollution. Adsorption selectivity as well as a large adsorption capacity are two key factors for treating wastewater containing multiple ions. Herein, a PPy+/TiO2(O-) composite with a heterojunction structure was first discovered to have novel selectivity toward heavy metal ions. An interesting self-doping nature of TiO2(O-) together with SO42- for PPy+ was reported. This interesting structure contributed to an impressive selective adsorption capability with an ascending order of Zn2+ > Pb2+ >> Cu2+ in a ternary ion system, where the adsorption for Cu2+ could be almost suppressed. Through the designed adsorption experiments and characterization techniques including Fourier transform infrared, thermogravimetric analysis, and X-ray photoelectron spectroscopy, a universal synergistic mechanism for PPy+/TiO2(O-) composite was first proposed and confirmed. The doping and dedoping of metal oxide (dopant) from the polymer dictates the adsorption selectivity, where the selectivity is determined by the interaction between TiO2 and heavy metal ions. This work may provide some useful guidelines for designing adsorbents with selectivity toward specific heavy metal ions.

关键词： selectivity Insight metal ions ADSORPTIVITY key factors Adsorption Selective adsorption heavy metal cation Composites Synergism

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