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The effects of the rotor-stator interaction on unsteady pressure pulsation and radial force in a centrifugal pump

Journal of Hydrodynamics 2018年第4期30卷 672-681页

作者： Issa Chalghoum Sami Elaoud Hatem Kanfoudi Mohsen Akrout research laboratory "Applied Fluid Mechanics Process and Environment Engineering" National Engineering School of Sfax Sfax Tunisia research laboratory "laboratory of hydraulics and environment modeling" National Engineering School of Tunis ENIT Hydraulic Engineering Tunis Tunisia

An unsteady numerical analysis has been conducted to study the strong interaction between impeller blade and volute tongue of a centrifugal pump. The 3-D-URANS equations were solved with the shear stress transport turbulence model for a wide range of flow rates. These unsteady interactions are mostly related to the unsteady radial force due to an imbalance in the pressure field at the impeller periphery. This force represents dynamic load that are one of the most important sources of vibration and hydraulic noise. Based on this phenomenon, this work analyzes and gives a more realistic prediction of the pressure fluctuation and the radial force during steady and unsteady calculation by considering the effect of the change in the pump operating point. Actually, the pressure fluctuations in the impeller and the volute were recorded by mounting nine monitoring points on the impeller and volute casing. The results of the existing analysis has proven that the pressure fluctuation is periodic due to the relative position of impeller blade to volute tongue. The characteristics of the time domain and frequency domain of the pressure pulsation were analyzed under different coupling conditions. Fast Fourier transform was performed to obtain the spectra of pressure pulsation. Besides, the steady and unsteady forces were calculated around the impeller periphery to fully characterize the pump behavior. The obtained pump performance curves were numerically compared with the experimental ones, and the outcome have shown an acceptable agreement between both curves.

关键词： Unsteady simulation blade-tongue interaction unsteady pressure distribution blade-passing frequency

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Turbulent lock release gravity current

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Science China(Technological Sciences) 2001年第5期44卷 449-462页

作者：陈国谦 Joseph H.w.Lee National laboratory for Turbulence research Department of Mechanics Peking University Beijing 100871China

The time evolution of a turbulent lock release gravity current, formed by a finite volume ofhomogeneous fluid released instantaneously into another fluid of slightly lower density, was studied byexperimental measurements of the density structure via elaborate digital image processing and by a nu-merical simulation of the flow and mixing using a two-equation turbulence model. The essential fact thatthe gravity current passes through an initial slumping phase in which the current head advances steadilyand a second self-similar phase in which the front velocity decreases like the negative third power of thetime after release is satisfactorily presented by the laboratory observation. An overall entrainment ratioproportional to the distance from the release point is found by the numerical simulation. The renormal-ization group (RNG) k- ε model for Reynolds-stress closure is validated to characterize the gravitycurrent with transitional and localized turbulence.

关键词： turbulence modeling, gravity current, environmental hydraulics.

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Quantitative modeling for Corrosion Behavior in Complex Coupled environment by Response Surface Methodology

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Acta Metallurgica Sinica(English Letters) 2015年第8期28卷 994-1001页

作者： Jing Liu Tao Zhang Wei Zhang Yan-Ge Yang Ya-Wei Shao Guo-Zhe Meng Fu-Hui Wang Corrosion and Protection laboratory Key Laboratory of Superlight Materials and Surface Technology (Harbin Engineering University) Ministry of Education laboratory for Corrosion and Protection Institute of Metal Research Chinese Academy of Sciences

Response surface methodology（RSM） is introduced into corrosion research as a tool to assess the effects of environmental factors and their interactions on corrosion behavior and establish a model for corrosion prediction in complex coupled environment（CCE）. In this study, a typical CCE, that is, the corrosion environment of pipelines in gas field is taken as an example. The effects of environmental factors such as chloride concentration, pH value and pressure as well as their interactions on critical pitting temperature（CPT） were evaluated, and a quadratic polynomial model was developed for corrosion prediction by RSM. The results showed that the model was excellent in corrosion prediction with R2= 0.9949. CPT was mostly affected by single environmental factor rather than interaction, and among the whole factors, chloride concentration was the most influential factor of CPT.

关键词： Response surface methodology Quantitative modeling 316L Stainless steel Critical pitting temperature

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Effects of benthic hydraulics on sediment oxygen demand in a canyon-shaped deep drinking water reservoir:Experimental and modeling study

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Journal of environmental Sciences 2021年第4期33卷 226-234页

作者： Nan Li Tinglin Huang Zhiying Chang Kai Li Key laboratory of Northwest Water Resource Environment and EcologyMOEXi’an University of Architecture and TechnologyXi’an 710055China Shaanxi Key laboratory of environmental Engineering Xi’an University of Architecture and TechnologyXi’an 710055China

Sediment oxygen demand(SOD)is a major contributor to hypolimnetic oxygen depletion and the release of internal nutrient *** measuring the SOD in experimental chambers using in both dissolved oxygen(DO)depletion and diffusional oxygen transfer methods,a model of SOD for a sediment bed with water current-induced turbulence was *** experimental study was also performed using near-sediment vertical DO profiles and correlated hydraulic parameters stimulated using a computational fluid dynamics model to determine how turbulences and DO concentrations in the overlying water affects SOD and diffusive boundary layer *** dependence of the oxygen transfer coefficient and diffusive boundary layer on hydraulic parameters was quantified,and the SOD was expressed as a function of the shear velocity and the bulk DO *** predictions were validated using microelectrode measurements in a series of laboratory *** study found that flow over the sediment surface caused an increase in SOD,attributed to enhanced sediment oxygen uptake and reduced substances fluxes,i.e.,for a constant maximum biological oxygen consumption rate,an increased current over the sediment could increase the SOD by 4.5 times compared to stagnant *** results highlight the importance of considering current-induced SOD increases when designing and implementing aeration/artificial mixing strategies.

关键词： Sediment oxygen demand Sediment-water flux Diffusive boundary layer thickness Turbulence Biological oxygen consumption

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Predictions of bulk velocity for open channel flow through submerged vegetation

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Journal of Hydrodynamics 2020年第4期32卷 795-799页

作者： Wei-jie Wang Xiao-yu Cui Fei Dong Wen-qi Peng Zhen Han Ai-ping Huang Xue-kai Chen Yuan Si State Key laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing 10003&China Department of Water Ecology and environment China Institute of Water Resources and Hydropower ResearchBeijing 100038China

Vegetation is of great significance in river ecosystems in terms of hydrodynamics,water environment and *** question of how to predict the bulk velocity in channel flow through submerged vegetation is currently a hot topic in hydraulics *** present study addresses this *** various formulae used for bulk velocity estimation in previous work were reviewed and *** main novelty of this paper is that a new expression of friction factor is proposed as a function of two dimensionless factors,and the number of tuning parameters is less than that in previous work.A comparison of measured and calculated data was conducted for flow through submerged rigid and flexible *** comparison showed that the proposed new model can make more accurate predictions than previous *** is envisaged that the proposed formulation can be usefully employed in eco-hydraulics predictions.

关键词： Vegetation resistance drag coefficient bulk velocity open channel flow

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modeling the corrosion behavior of Ni-Cr-Mo-V high strength steel in the simulated deep sea environments using design of experiment and artificial neural network

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Journal of Materials Science & Technology 2019年第1期35卷 168-175页

作者： Qiangfei Hu Yuchen Liu Tao Zhang Shujiang Geng Fuhui Wang School of Metallurgy Northeastern University Corrosion and Protection Division Shenyang National Laboratory for Materials Science Northeastern University laboratory for Corrosion and Protection Institute of Metal Research Chinese Academy of Sciences

Corrosion in complex coupling environments is an important issue in corrosion field, because it is difficult to take into account a large number of environment factors and their interactions. Design of Experiment(DOE) can present a methodology to deal with this difficulty, although DOE is not commonly spread in corrosion field. Thus, modeling corrosion of Ni-Cr-Mo-V steel in deep sea environment was performed in order to provide example demonstrating the advantage of DOE. In addition, an artificial neural network mapping using back-propagation method was developed for Ni-Cr-Mo-V steel such that the ANN model can be used to predict polarization curves under different complex sea environments without experimentation. Furthermore, roles of environment factors on corrosion of Ni-Cr-Mo-V steel in deep sea environment were discussed.

关键词： Ni-Cr-Mo-V steel Deep sea corrosion Design of experiment Artificial neural network

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Numerical investigation of the effects of soil-structure and granular material-structure interaction on the seismic response of a flat-bottom reinforced concrete silo

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Earthquake Engineering and Engineering Vibration 2024年第3期23卷 609-623页

作者： Sonia Benkhellat Mohammed Kadri Abdelghani Seghir laboratory of Solid Mechanics and Systems University of M’Hamed BougaraBoumerdes 35000Algeria laboratory of Geomaterials Environment and DevelopmentUniversity of M’Hamed BougaraBoumerdes 35000Algeria research laboratory of Applied hydraulics and environment Faculty of TechnologyUniversity of BejaiaBejaia 06000Algeria

In this work,a numerical study of the effects of soil-structure interaction(SSI)and granular material-structure interaction(GSI)on the nonlinear response and seismic capacity of flat-bottomed storage silos is conducted.A series of incremental dynamic analyses(IDA)are performed on a case of large reinforced concrete silo using 10 seismic *** IDA results are given by two average IDA capacity curves,which are represented,as well as the seismic capacity of the studied structure,with and without a consideration of the SSI while accounting for the effect of *** curves are used to quantify and evaluate the damage of the studied silo by utilizing two damage indices,one based on dissipated energy and the other on displacement and dissipated *** cumulative energy dissipation curves obtained by the average IDA capacity curves with and without SSI are presented as a function of the base shear,and these curves allow one to obtain the two critical points and the different limit states of the *** is observed that the SSI and GSI significantly influence the seismic response and capacity of the studied structure,particularly at higher levels of ***,the effect of the SSI reduces the damage index of the studied structure by 4%.

关键词： reinforced concrete silo perfectly matched layers soil-structure interaction granular material-structure interaction effective seismic input method damage index

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Study of a Hydraulic Jump in an Asymmetric Trapezoidal Channel with Different Sluice Gates

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Fluid Dynamics & Materials Processing 2024年第7期20卷 1499-1516页

作者： Bouthaina Debabeche Sonia Cherhabil research laboratory in Civil Engineering HydraulicsSustainable Development and Environment(LARGHYDE)University of BiskraBiskra7000Algeria Faculty of Sciences Applied Sciences Liege UniversityLiege4000Belgium Underground and Surface hydraulics research laboratory(LARHYSS) Biskra7000Algeria

In this study,the main properties of the hydraulic jump in an asymmetric trapezoidal flume are analyzed experimentally,including the so-called sequent depths,characteristic lengths,and *** particular,an asymmetric trapezoidal flume with a length of 7 m and a width of 0.304 m is considered,with the bottom of the flume transversely inclined at an angle of m=0.296 and vertical lateral *** corresponding inflow Froude number is allowed to range in the interval(1.405,the hydraulic jump is found to be more effective than that occurring in triangular and symmetric trapezoidal ***,when■mes>8 and■>5,the hydraulic jump in the asymmetrical trapezoidal channel downstream of a parallelogram sluice gate is completely formed as opposed to the situation where a triangular sluice is considered.

关键词： Asymmetric trapezoidal channel characteristic lengths efficiency Froude hydraulic jump sequent depths sluice gate

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Large-scale industrial manufacturing of carbon nanotubes in a continuous inclined mobile-bed rotating reactor via the catalytic chemical vapor deposition process

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Frontiers of Chemical Science and Engineering 2017年第2期11卷 280-289页

作者： Sophie L. Pirard Sigrid Douven Jean-Paul Pirard laboratory of Chemical Engineering Department of Chemical Engineering University of Liege B-4000 Liege Belgium

This article reports the different steps of the design, development and validation of a process for continuous production of carbon nanotubes （CNTs） via catalytic chemical vapor deposition from the laboratory scale to the industrial production. This process is based on a continuous inclined mobile-bed rotating reactor and very active catalysts using methane or ethylene as carbon source. The importance of modeling taking into account the hydrodynamic, physicochemical and physical phenomena that occur during CNT production in the process analysis is emphasized. The impact of this invention on the environment and human health is taken into consideration too.

关键词： carbon nanotubes catalytic chemical vapor deposition inclined rotating reactor industrial process scaling-up

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EFFECT OF DISCHARGE RATIO ON FLOW CHARACTERISTICS IN 90°EQUAL-WIDTH OPEN-CHANNEL JUNCTION

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Journal of Hydrodynamics 2009年第4期21卷 541-549页

作者： ZHANG Ting XU Wei-lin WU Chao College of Civil Engineering Fuzhou University Fuzhou 350108 China State Key laboratory of hydraulics and Mountain River Engineering Sichuan University Chengdu 610065 China

For the 90° equal-width open-channel junction flow, the Reynolds averaged Navier-Stokes equations are solved while using the 3-D κ- ω model. The mean flow pattern and the secondary current are obtained. The model is validated by experimental data, and then applied to investigate the effect of the discharge ratio on the shape of separation zone shape, the cross-sectional mean flow angle and the contraction coefficient. The results are fairly close to those of the prior studies. The numerical modeling is both less time-consuming and less expensive to obtain the various flow parameters needed for engineering design.

关键词： κ- ω turbulent model open-channel junction separation zone secondary current

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