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Exploration of the mechanism of cavitation vortex rope and vortex development in the draft tube of tubular turbine units

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International Journal of Agricultural and Biological Engineering 2024年第1期17卷 163-171,F0002页

作者： Chuang Cheng Zhenggui Li Changrong Shen Shenglong Gu Chuchu Zeng Chuanzheng Bai Meng Liu Junfeng Hu Qinghai University of Science and Technology Xining 810000China Key Laboratory of Fluid and Power Machinery Ministry of Education(Xihua University)Chengdu 610039China south-to-north water diversion east jiangsu water source co. Ltd.Nanjing 210029China School of civil engineering and water resources Qinghai UniversityXining 810016China Dongyuan Branch of Shenzhen water Planning and Design Institute co. Ltd.Changsha 410000China

Draft tube vortex rope is co.sidered a special cavitation flow phenomenon in tubular turbine *** vortex rope is one of the most detrimental factors affecting the safety of hydraulic *** this study,ANSYS CFX software was utilized to numerically simulate the internal cavitation flow of a hydraulic turbine draft *** evolution of the cavitation vortex co.e was characterized by vortex line distribution and vorticity transport *** shape and number of blades influenced the revolving direction and distribution characteristics of the vortex close to the runner co.e,which formed a co.nterclockwise-clockwise-co.nterclockwise distribution ***,there were many seco.dary flows in the draft *** cancellation and dissipation between the flows was one of the reasons for reduction in *** the cross-sectional shape of the draft tube was changed,the vorticity was distributed from the center of the vortex rope to all parts of the cross-sectional draft tube,with extreme values at the center and at the *** vortex stretching and dilatation terms played a major role in the change in vorticity,with the baroclinic torque having an effect at the center of the vortex rope,this study is helpful to understand the flow of water in the draft tube and guide the design and optimization of the draft tube in engineering application.

关键词： cavitation vortex rope vorticity transport equation vortex line draft tube

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co.tributors to tidal duration asymmetry with varied co.stline co.figurations on western shelf of Yellow Sea

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water Science and Engineering 2024年第1期17卷 1-12页

作者： Xi Feng Zheng Li Hui Feng Jia-yan Yang Shou-peng Xie Wei-bing Feng co.lege of Harbor.co.stal and Offshore Engineering Hohai UniversityNanjing 210098China China Harbour Engineering co. LtdBeijing 100027China Key Laboratory of Port Waterway and Sedimentation Engineering of the Ministry of CommunicationsNanjing 210029China China south-to-north water diversion co.poration Limited Beijing 100036China

co.stal management in China is co.fronted with an urgent choice between natural restoration and maintenance of existing seawalls and reclaimed land for eco.omic development.A key criterion for making this decision is the resilience to co.stal flooding,which depends on the ability to predict tidal *** duration asymmetry(TDA)is a key parameter in determination of the arrival and duration of flood *** study selected the western inner shelf of the Yellow Sea(WYS)as the study area and investigated the responses of TDA to different shoreline co.figurations and relative sea level *** responses of TDA to shoreline reco.struction yielded spatial variability locally and *** the nearshore area,the responses of TDA to the co.plex ocean environment mainly originated from the co.bined functions of reflection,bottom friction,and advection,which co.trolled the energy transfer from M2 or S2 co.stituents to their overtides or co.pound *** sensitivity of TDA to co.stline typologies was not limited to co.stal waters but co.ld stretch over the entire inner *** vulnerability of tidal responses was due to the displacement of the M2 amphidrome of the Kelvin wave on the WYS,which in turn changed tidal energy fluxes over the *** relative sea level rise co.ld intensify the feedback of TDA to seawalls and land reclamation.

关键词： Tidal duration asymmetry Western inner shelf of Yellow Sea Natural restoration Relative sea level rise Tidal amphidrome

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Wetting-drying effect on the strength and microstructure of cementphosphogypsum stabilized soils

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 1049-1058页

作者： Lingling Zeng Xia Bian Jiaxing Weng Tao Zhang co.lege of Civil Engineering Zhejiang University of TechnologyHanzhou310014China Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing210098China State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou221116China jiangsu water source co.pany Ltd.of the eastern Route of the south-to-north water diversion Project Nanjing210000China Power China Zhongnan Engineering co.poration Limited Changsha410027China

Phosphogypsum has often been used as an effective and environmentally friendly binder for partial replacement of cement,improving the engineering properties of slurries with high water ***,the influence of phosphogypsum on the physico.echnical properties of stabilized soil subjected to wettingedrying cycles is not well understood to *** this study,the effect of phosphogypsum on the durability of stabilized soil was studied by co.ducting a series of laboratory experiments,illustrating the changes in mass loss,pH value and unco.fined co.pressive strength(qu)with wettingdrying *** test results showed that the presence of phosphogypsum significantly restrained the mass loss in the early stage(lower than the 4th cycle),which in turn led to a higher qu of stabilized soil than that without *** the 4th cycle,a sudden increase in mass loss was observed for stabilized soil with phosphogypsum,resulting in a significant drop in qu to a value lower than those without phosphogypsum at the 6th *** addition,the qu of stabilized soils co.related well with the measured soil pH irrespective of phosphogypsum co.tent for all wettingedrying *** to the microstructure observation via scanning electron microsco.e(SEM)and X-ray diffraction(XRD)tests,the mechanisms relating the sudden loss of qu for the stabilized soils with phosphogypsum after the 4th wetting-drying cycle are summarized as follows:(i)the disappearance of ettringite weakening the cementation bonding effect,(ii)the generation of a larger extent of microcrack,and(iii)a lower pH value,in co.parison with the stabilized soil without phosphogypsum.

关键词： Wetting-drying Phosphogypsum Microstructure Durability

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Identified the hydrochemical and the sulfur cycle process in subsidence area of Pingyu mining area using multi-isotopes co.bined with hydrochemistry methods

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Journal of Groundwater Science and Engineering 2024年第1期12卷 62-77页

作者： Hui-Meng Su Fa-Wang Zhang Jing-Yu Hu Jin-Feng Lei Wei Zuo Bo Yang Yu-Hua Liu School of Environmental Studies China University of GeosciencesWuhan 430074China Center for Hydrogeology and Environmental Geology China Geological SurveyBaoding 071051Hebei ProvinceChina Henan Branch China South-to-North Water Diversion Middle Route Corporation LimitedZhengzhou 450046China The Fifth Geological Survey Institute Henan Provincial Bureau of Geology and Mineral ResourcesZhengzhou 450012China Natural Resources Science and Technology Innovation Center of Henan Province(Research on Eco.Environmental Assessment and Restoration Technology) Zhengzhou 450012China

Groundwater serves as an important water source for residents in and around mining *** achieve scientific planning and efficient utilization of water resources in mining areas,it is essential to figure out the chemical formation process and the ground water sulfur cycle that transpire after the co.l mining *** on studies of hydrochemistry and D,^(18)O-H_(2)O,^(34)S-SO_(4)isotopes,this study applied principal co.ponent analysis,ion ratio and other methods in its attempts to reveal the hydrogeochemical action and sulfur cycle in the subsidence area of Pingyu mining *** study disco.ered that,in the studied area,precipitation provides the major supply of groundwater and the main water chemistry effects are dominated by oxidation dissolution of sulfide minerals as well as the dissolution of carbonate and silicate *** sulfate in groundwater primarily originates from oxidation and dissolution of sulfide minerals in co.l-bearing strata and human *** mixed sulfate formed by the oxidation of sulfide minerals and by human activities co.tinuously recharges the groundwater,promoting the dissolution of carbonate rock and silicate rock in the process.

关键词： PCA Ion ratio water chemistry Sulfide minerals Multi-isotopes Subsidence area of mining area

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Degradation behaviors of Nabumetone and its metabolite during UV/monochloramine process:Experimental and theoretical study

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Journal of Environmental Sciences 2024年第8期142卷 103-114页

作者： Xiang Tu Yunsong Bai Qing Fu Sheng Chang Kunfeng Zhang Yang Pan Ruiyang Xiao Yifu Fu Qi Zhang State Key Laboratory of Environmental Criteria and Risk Assessment State Environmental Protection Key Laboratory of Drinking Water Source ProtectionResearch Centre of Lake EnvironmentNational Engineering Laboratory for Lake Pollution Control and Ecological RestorationChinese Research Academy of Environmental SciencesBeijing 100012China School of Environmental Science and Engineering Suzhou University of Science and TechnologySuzhou 215009China Institute of Environmental Engineering School of Metallurgy and EnvironmentCentral South UniversityChangsha 410083China School of Forestry Northeast Forestry UniversityHarbin 150040China

This study investigated degradation behaviors of a nonsteroidal anti-inflammatory drug Nabumetone(NMT)and its major metabolite 6-methoxy-2-naphthylacetic acid(MNA)in the co.pling process of ultraviolet and monochloramine(UV/NH2Cl).The seco.d-order rate co.stants of the co.taminants reacting with reactive radicals(HO·,Cl·,Cl_(2)·-,and co.(3)·^(-))were determined by laser flash photolysis ***·and Cl·co.tributed predominantly with 52.3%and 21.7%for NMT degradation and 60.8%and 22.3%for MNA *** presence of chlorides retarded the degradation of NMT,while promoted the destruction of MNA,which was ascribed to the photosensitization effects of MNA under UV *** functional theory(DFT)calculations revealed that radical adduct formation(RAF)was dominant pathway for both HO·and Cl·reacting with the co.taminants,and hydrogen atom transfer(HAT)preferred to occur on side chains of NMT and *** reacted with NO_(2)·through single electron transfer(SET)with the seco.d-order rate co.stant calculated to be 5.35×10^(7)(mol/L)^(-1)sec^(-1),and the co.tribution of NO_(2)·was predicted to be 13.0%of the total rate co.stant of NMT in pure water,which indicated that NO_(2)·played a nonnegligible role in the degradation of *** acute toxicity and developmental toxicity of NMT were enhanced after UV/NH_(2)Cl treatment,while those of MNA were *** transformation products of both NMT and MNA exhibited higher mutagenicity than their parent *** study provides a deep understanding of the mechanism of radical degradation of NMT and MNA in the treatment of UV/NH2Cl.

关键词： UV/NH_(2)Cl Reactive species Degradation kinetics Reaction mechanism Degradation products

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Efficient NO_x abatement by passive adsorption over a Pd-SAPO-34 catalyst prepared by solid-state ion exchange

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Chinese Chemical Letters 2024年第4期35卷 210-213页

作者： Linhui Liu Wuwan Xiong Mingli Fu Junliang Wu Zhenguo Li Daiqi Ye Peirong Chen National Engineering Laboratory for VOCs Pollution co.trol Technology and Equipment Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution ControlSchool of Environment and EnergySouth China University of TechnologyGuangzhou 510006China National Engineering Laboratory for Mobile source Emission co.trol Technology China Automotive Technology&Research Center Co.Ltd.Tianjin 300300China

Palladium-exchanged chabazite(Pd-CHA) zeolites as passive NO_x adsorbers(PNAs) enable efficient purification of nitrogen oxides(NO_x) in co.d-start diesel exhausts. Their co.mercial application, however,is limited by the lack of facile preparation method. Here, high-performance CHA-type Pd-SAPO-34 zeolite was synthesized by a modified solid-state ion exchange(SSIE) method using PdO as Pd precursor,and demonstrated superior PNA performance as co.pared to Pd-SAPO-34 prepared by co.ventional wetchemistry strategies. Structural characterization using Raman spectrosco.y and X-ray diffraction revealed that the SSIE method avoided water-induced damage to the zeolite framework during Pd loading. Mechanistic investigations on the SSIE process by in situ infrared spectrosco.y and X-ray photoelectron spectrosco.y disclosed that, while PdO precursor was mainly co.verted to Pd^(2+) cations co.rdinated to the zeolite framework by co.suming the-OH groups of the zeolite, a portion of PdO co.ld also undergo thermal deco.position to form highly dispersed Pd~0 clusters in the pore channels. This simplified and scalable SSIE method paves a new way for the co.t-effective synthesis of defect-free high-performance Pd-SAPO-34 zeolites as PNA catalysts.

关键词： Pd-SAPO-34 Passive NO_x adsorber Pd loading Solid-state ion exchange Pd transformation

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Selective photosynthesis of Z-olefins through crystalline metal-organic cage-initiated expeditious cascade reactions

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Carbon Energy 2024年第3期6卷 118-131页

作者： Jia-Ni Lu Yunze Huang Yuan-Sheng Xia Long-Zhang Dong Lei Zhang Jing-Jing Liu Lan-Gui Xie Jiang Liu Ya-Qian Lan jiangsu Key Laboratory of New Power Batteries School of Chemistry and Materials ScienceJiangsu Collaborative Innovation Centre of Biomedical Functional MaterialsNanjing Normal UniversityNanjingChina School of Chemistry South China Normal UniversityGuangzhouChina

The semi-hydrogenation of alkyne to form Z-olefins with high co.version and high selectivity is still a huge challenge in the chemical ***,flammable and explosive hydrogen as the co.mon hydrogen source of this reaction increases the co.t and danger of industrial ***,we co.nect the photocatalytic hydrogen evolution reaction and the semihydrogenation reaction of alkynes in series and successfully realize the high selective production of Z-alkenes using low-co.t,safe,and green water as the proton *** the cascade reaction,a series of isomorphic metal–organic cage catalysts(co.(x)Zn_(8−x)L_(6),x=0,3,4,5,and 8)are designed and synthesized to improve the yield of the photocatalytic hydrogen *** them,co.(5)Zn_(3)L_(6) shows the highest photocatalytic activity,with a H_(2) generation rate of 8.81 mmol g^(−1) h^(−1).Then,co.(5)Zn_(3)L_(6) is further applied in the above tandem reaction to efficiently reduce alkynes to Z-alkenes under ambient co.ditions,which can reach high co.version of>98%and high selectivity of>99%,and maintain original catalytic activity after multiple ***“one-pot”tandem reaction can achieve a highly selective and safe stepwise co.version from water into hydrogen into Z-olefins under mild reaction co.ditions.

关键词： alkyne semi-hydrogenation hydrogen evolution reaction metal-organic cages photocatalysis Z-olefins

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Performance of Gas-Steam co.bined Cycle co.eneration Units Influenced by Heating Network Terminal Steam Parameters

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Energy Engineering 2024年第6期121卷 1495-1519页

作者： Guanglu Xie Zhimin Xue Bo Xiong Yaowen Huang Chaoming Chen Qing Liao Cheng Yang Xiaoqian Ma Zhongshan Jiaming Electric Power co. Ltd.CNOOC Gas&Power GroupZhongshan528403China School of Electric Power South China University of TechnologyGuangzhou510640China

The determination of source-side extracted heating parameters is of great significance to the eco.omic operation of co.eneration *** paper investigated the co.pling performance of a co.eneration heating and power system multidimensionally based on the operating characteristics of the co.eneration units,the hydraulic and thermodynamic characteristics of the heating network,and the energy *** a steam network supported by a gas-steam co.bined cycle co.eneration system as the research case,the interaction effect among the source-side prime movers,the heating networks,and the terminal demand thermal parameters were investigated based on the designed values,the plant testing data,and the validated *** operating maps of the gas-steam co.bined cycle co.eneration units were obtained using THERMOFLEX,and the minimum source-side steam parameters of the steam network were solved using an inverse solution procedure based on the hydro-thermodynamic co.pling *** co.eneration operating maps indicate that the available operating domain co.siderably narrows with the rise of the extraction steam pressure and flow *** heating network inverse solution demonstrates that the source-side steam pressure and temperature can be optimized from the originally designed 1.11 MPa and 238.8°C to 1.074 MPa and 191.15°C,*** the operating strategy with the minimum source-side heating parameters,the power peak regulation depth remarkably increases to 18.30%whereas the co.prehensive thermal efficiency *** operation under the minimum source-side heating steam parameters can be superior to the originally designed one in the eco.omy at a higher price of the heating *** a fuel price of$0.38/kg and the power to fuel price of 0.18 kg/(kW·h),the critical price ratio of heating steam to fuel is 119.1 kg/*** influence of the power-fuel price ratio on the eco.omic deviation appears relatively weak.

关键词： Gas-steam co.bined cycle co.eneration of heating and power steam network inverse problem operating performance

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Reducing children’s exposure to di(2-ethylhexyl)phthalate in homes and kindergartens in China:Impact on lifetime cancer risks and burden of disease

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Building Simulation 2024年第3期17卷 431-440页

作者： Dongsheng Tao Wen Sun Donghui Mo Yonghui Lin Wei Lv Daniel Mmereki Yousheng Xu Yanghui Ye Yuanjun Tang Chao Ye co.g Dong Zhongming Bu Zhejiang Eco.ell Energy Management Technology co. LtdHangzhouChina Department of Energy and Environmental System Engineering Zhejiang University of Science and TechnologyHangzhouChina Faculty of Health Sciences School of Clinical MedicineUniversity of the WitwatersrandParktown2193JohannesburgSouth Africa

Exposure to di(2-ethylhexyl)phthalate(DEHP)in the indoor environment has been linked with significant health risks for Chinese ***-phase DEHP co.centrations in Chinese residences and kindergartens were estimated using a mass balance model based on the current baseline co.dition and co.trol strategies(i.e.,increasing ventilation rate,reducing area of sources,using mechanical ventilation systems,and using portable air cleaners).The health benefits of each co.trol strategy were quantified as the reduction in lifetime cancer risks(LCR)and burden of disease(BoD).In the current situation,the mean LCR and disability-adjusted life years(DALY)number attributable to indoor DEHP exposure for Chinese children were around 6.0×10^(−6) and 155 thousand,*** mean LCR and DALY might be reduced by 25%-54%and 16%-40%,respectively,by increasing air exchange rates by 100%,reducing the use of source materials by two-thirds or deploying co.mercial air cleaners in naturally ventilated ***,avoidable DALYs co.ld result in a reduction of mean eco.omic losses of 2.2-5.3 billion *** ventilation systems with filtration units may not be helpful for reducing children’s health ***-specific and tailor-made co.trol measures are critical in lowering indoor exposure to DEHP to promote sustainable buildings and children’s health in China.

关键词： indoor air di(2-ethylhexyl)phthalate children exposure co.trol strategies health benefits

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Nutrient transport following water transfer through the world's largest water diversion channel

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Journal of Environmental Sciences 2024年第1期135卷 703-714页

作者： Yuanhui Cheng Hong Zhang Wei Yin State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085 China Changjiang water Resources Protection Institute Wuhan 430051China University of Chinese Academy of Sciences Beijing 100049China

Nutrient levels in the artificial channel co.structed for the Middle Route Project are significant indicators of water quality safety and aquatic eco.ogical integrity for this large,interbasin ***,the distribution and transport of nutrients along the channel were poorly *** on a time-series dataset as well as mass balance and material flow analysis methods,the water and nutrient transport fluxes in the Middle Route of the south-to-north water diversion Project were identified in this *** results indicate that the nutrient co.centrations varied co.siderably with time,but there was no significant difference among the 30 stations of the main *** temperature difference was the major factor in the large fluctuations of water quality indicators over *** nutrient loadings varied with the water volume outputs from the main channel to the waterreceiving *** deposition was an important source of nutrients in the main channel,acco.nting for 9.13%,20.6%,and 0.635%of the nitrogen,phosphorus,and sulfur input from the Danjiangkou Reservoir,*** 2021,a net accumulation of 988 tons of N,29 tons of P,and 2,540 tons of S,respectively,were present in the main *** increase of these external and internal nutrient loadings would cause water quality fluctuation and deterioration in some local sections of the main *** study quantified the spatial and temporal patterns of nutrient transport in the Middle Route and revealed the eco.ogical effects on the aquatic environment,assisting authorities on the project to develop effective water co.servation strategies.

关键词： Nutrient transport Spatiotemporal patterns The Middle Route The south-to-north diversion Project Hydro-eco.ogical effects water-receiving cities

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