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CFD simulation with enhancement factor of sulfur dioxide absorption in the spray scrubber

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第11期9卷 1601-1613页

作者： Xiang GAO Wang HUO Zhong-yang LUO Ke-fa CEN State Key Laboratory of Clean Energy Utilization Institute for Thermal Power Engineering Zhejiang University Hangzhou 310027 China

A model describing the absorption process of SO2 into limestone slurry with a spray scrubber is presented. Both the physical performance of the spray liquid in the scrubber and the involved chemical reactions are analyzed in the model. A con- tinuous concentration change of H+ was solved by iterative coupling using Matlab, and it was found that there was a remarkable influence on the concentration of the other elements in the process of SO2 absorption. The calculations show that the enhancement factor exponentially grows with an increasing value of pH and logarithmically decays with an increasing value of the driving force. To verify the accuracy of the model, experiments were also carried out, and the results suggest that the model, after combining the physical performance of the spray and the enhancement factor, can more precisely describe SO2 absorption in a spray scrubber. Furthermore, a commercial computational fluid dynamics (CFD) tool is used to perform several simulations which describe and clarify the effects of variables on SO2 absorption. The results of numerical simulation can provide a basis for further design and optimization of the scrubber.

关键词： SO2 absorption Limestone dissolution Enhancement factor Mass transfer concentration profile

Salt transport in polymeric pervaporation membrane

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Chinese Journal of Chemical Engineering 2020年第3期28卷 758-765页

作者： Dihua Wu Aoran Gao Xianshe Feng College of Materials and Environmental Engineering Hangzhou Dianzi UniversityXiasha Higher Education ZoneHangzhou 310018China Department of Chemical Engineering University of Waterloo200 University Avenue WestWaterloo N2L 3G1OntarioCanada

The salt transport in a PEBA membrane used in pervaporative desalination was *** concentration profile of salt in the membrane during pervaporation was investigated experimentally using a multilayer *** salt was found to be sorbed in the membrane but was not removed during the pervaporative desalination process,and the salt concentration in the membrane varied linearly with *** purity water was obtained as the permeate as long as the permeate side was kept dry under *** accumulated salt uptake in the membrane follows the order of MgCl2 N NaCl N Na2 *** solubility of salt in the membrane follows the order of MgCl2 N NaCl N Na2 *** the permeability and diffusivity of salt in the membrane follow the order of NaCl N MgCl2 N Na2 *** permeability of salt in the membrane is not influenced by the feed salt *** is mainly determined by the diffusion coefficients.

关键词： concentration profile Pervaporative desalination Salt transport

Effect of Aluminum and Silicon on Transformation Induced Plasticity of the TRIP Steel

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Journal of Materials Science & Technology 2004年第2期20卷 135-138页

作者： LinLI B.C.DeCoomant P.Wollants YanlinHE XiaodongZHOU Dept.Mater.Sci.&Eng. ShanghaiUniversity149YanchangRoadShanghai200072China LaboratoryforIronandSteelmaking UniversiteitGentTechnologiepark9B-9052ZwijnaardeBelgium Dept.MTM KatholiekeUniversiteitLeuvenKasteelparkArenberg44B-3001LeuvenBelgium ShanghaiBaosteelResearchInstitute FujinRoadShanghai201900China

With the sublattice model, equilibrium compositions of ferrite (a) and austenite (7 ) phases, as well as the volume percent of austenite (7) at 780℃ in different TRIP steels were calculated. concentration profiles of carbon, Mn, Al and Si in the steels were also estimated under the lattice fixed frame of reference so as to understand the complex mechanical behavior of TRIP steels after different isothermal bainitic transformation treatments. The effect of Si and Mn on transformation induced plasticity (TRIP) was discussed according to thermodynamic and kinetic analyses. It is recognized that Al also induces phase transformation in the steels but its TRIP effect is not as strong as that of Si.

关键词： Equilibrium composition concentration profile Thermodynamic Kinetic

CALCULATION MODELS FOR THE SUSPENDED SEDIMENT TRANSPORT RATE

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Journal of Hydrodynamics 1993年第1期5卷 10-21页

作者： Ni, Jinren Peking Univ Beijing China

The calculation accuracy of the suspended sediment transport rate relies on that of the vertical distribution of the particle concentration,the particle velocity distribution and the reference *** view of the limitations of the previons formulas for both the velocity and the concentration distributions,general expressions are introduced to the calculation of sus- pended sediment transport *** on these analyses,a simple and practical calculation model is given in the present paper.

关键词： suspended sediment transport rate concentration profile

Stochastic formulation of particle kinetics in wall-bounded two-phase flows

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Science China(Technological Sciences) 2014年第10期57卷 2001-2011页

作者： MA HongBo FU XuDong State Key Laboratory of Hydroscience and Engineering Department of Hydraulic Engineering Tsinghua University

This paper presents a generalized framework of stochastic modeling for particle kinetics in wall-bounded *** modified a reflected Brownian motion process and straightforwardly obtained a Kramers equation for particle probability density function(PDF).After the wall effects were accounted for as a drift from zero in the mean displacement and suppression in the diffusivity of a particle,an analytical solution was worked out for *** distinguishable mechanisms were identified to affect the profile of particle probability distribution:external forces,turbophoresis effect,and wall-drift *** proposed formulation covers the Huang et al.(2009)model of a wall that produces electrostatic repulsion force and van der Waals force,as well as Monte-Carlo solutions for the Peter and Barenbrug(2002)model under a variety of relaxation ***,it successfully reproduces the two patterns of particle concentration profiles observed in experiments of sediment-laden open-channel *** strength of the wall-drift effect was found to be connected with the interaction frequency between particle and *** exploration of the relationship among flow turbulence,particle inertia,and particle concentration is worthwhile.

关键词： stochastic formulation Kramers equation reflected Brownian motion wall-bounded flow two-phase flow concentration profile

Computer-Aided Design of Some Advanced Steels and Cemented Carbides

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Journal of Iron and Steel Research International 2005年第6期12卷 42-48页

作者： LI Lin ZHANG Mei HE Yan-lin De Cooman Bruno Wollants Patrick Shanghai University Shanghai 200072 China Katholieke Universiteit Leuven Leuven 13-3001 Belgium Universiteit Gent Zwijnaarde 13-9052 Belgium

Thermodynamic and kinetic study on TRIP （transformation induced plasticity） steels, cemented carbides and mold steel for plastics were carried out in order to design modern advanced materials. With the sublattice model, equilibrium compositions of ferrite and austenite phases in TRIP steels, as well as volume fraction of austenite at inter-critical temperatures for different time were calculated. concentration profiles of carbon, manganese, aluminum and silicon in the steels were also estimated in the lattice fixed frame of reference. The effect of Si and Mn on TRIP was discussed according to thermodynamic and kinetic analyses. In order to understand and produce the graded nanophase structure of cemented carbides, miscellaneous phases in the M-Co-C （M= Ti, Ta, Nh） systems and Co-V-C system were modeled. Solution parameters and thermodynamic： properties were listed in detail. The improvement of machining behavior of prehardened mould steel for plastics was obtained by computer-aided composition design. The results showed that the matrix composition of large-section prehardened mould steel for plastic markedly influences the precipitation of non-metallic inclusion and the composition control by the aid of Thermo-Calc software package minimizes the amount of detrimental oxide inclusion. In addition, the modification of calcium was optimized in composition design.

关键词： computer-aided composition design TRIP steel cemented carbide prehardened mould steel concentration profile thermodynamic kinetic equilibrium composition

Experimental study on the effects of artificial bed roughness on turbidity currents over abrupt bed slope change

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International Journal of Sediment Research 2020年第3期35卷 256-268页

作者： Sara Baghalian Masoud Ghodsian Civil and Environmental Engineering Tarbiat Modares University Civil and Environmental Engineering and Water Engineering Research Institute Tarbiat Modares University

A series of experimental observations are presented in the current study to discuss the effects of artificial bed roughness on the turbidity current flowing in a rectangular channel with an abrupt change in bed *** this purpose,two different types of elements,sinusoidal and trapezoidal,with various heights and arrangements are considered as artificial bed roughness.A Vectrino velocity meter was used to measure the velocity and sediment concentration *** effects of inlet sediment concentration on front velocity,body velocity,unit discharge,sediment concentration,and suspended load transport rate also were *** equations were developed for estimation of the velocity of a turbidity current over smooth and rough *** unexpected experimental results showed that unlike the effect of roughness height,a change in the roughness arrangement has no significant influence on the velocity of a turbidity ***,the effect of bed roughness on the front velocity of a denser current is more significant.

关键词： Experimental analysis Turbidity current Bed roughness Slope break Velocity profile concentration profile

profile of Methane concentrations in Soil and Atmosphere in Alpine Steppe Ecosystem on Tibetan Plateau

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Chinese Journal of Population,Resources and Environment 2009年第1期7卷 3-10页

作者： Pei Zhiyong Ouyang Hua Zhou Caiping Xu Xingliang The Administrative Center for China＇s Agenda 21 Beijing 100038 China Interntional Center for Integrated Mountain Development Kathmanda Nepal Institute of Geographical Sciences and Natural Resources Research CAS Beijing 100101 China

The methane concentration profile from -1.5m depth in soil to 32m height in air was measured in alpine steppe lo-cated in the permafrost area. Methane concentrations showed widely variations both in air and in soil during the study period. The mean concentrations in atmosphere were all higher than those in soil, and the highest methane concentration was found in air at the height of 16m with the lowest concentration occur-ring at the depth of 1.5m in soil. The variations of atmospheric methane concentrations did not show any clear pattern both temporally and spatially, although they exhibited a more steady-stable state than those in soil. During the seasonal variations, the methane concentrations at different depths in soil were sig-nificantly correlated (R2>0.6) with each other comparing to the weak correlations (R2concentrations in soil significantly decreased with depth. This was the compositive influence of the decreasing production rates and the increasing methane oxidation rates, which was caused by the descent soil moisture with depth. Although the methane concentrations at all depths varied widely during the growing season, they showed very distinct temporal variations in the non-growing season. It was indicated from the literatures that methane oxidation rates were positively correlated with soil temperature. The higher methane concentrations in soil during the winter were deter-mined by the lower methane oxidation rates with decreasing soil temperatures, whereas methane production rates had no reaction to the lower temperature. Relations between methane contribution and other environmental factors were not discussed in this paper for lacking of data, which impulse us to carry out further and more detailed studies in this unique area.

关键词： methane concentration profile temperature moisture alpine steppe Tibetan Plateau

EFFECT　OF　FINE　PARTICLES　ON　THE　VERTICAL　concentration　DISTRIBUTION　AND　TRANSPORT　RATE　OF　COARSE　PARTICLES

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International Journal of Sediment Research 1994年第1期 13-30页

作者： WAN Zhaohui SONG Tiancheng

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关键词： concentration profile sediment transport rate,Bingham fluid yield stress rigidity diffusion theory modified Reynolds number drag coefficient .