期刊文献+
共找到15篇文章
< 1 >
每页显示 20 50 100
COMPUTATIONAL FLUID DYNAMICS RESEARCH ON PRESSURE LOSS OF CROSS-FLOW PERFORATED MUFFLER 被引量:15
1
作者 HU Xiaodong ZHOU Yiqi +2 位作者 FANG Jianhua MAN Xiliang ZHAO Zhengxu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2007年第2期88-93,共6页
The pressure loss of cross-flow perforated of physical modeling, simulation and data processing. muffler has been computed with the procedure Three-dimensional computational fluid dynamics (CFD) has been used to inv... The pressure loss of cross-flow perforated of physical modeling, simulation and data processing. muffler has been computed with the procedure Three-dimensional computational fluid dynamics (CFD) has been used to investigate the relations of porosities, flow velocity and diameter of the holes with the pressure loss. Accordingly, some preliminary results have been obtained that pressure loss increases with porosity descent as nearly a hyperbolic trend, rising flow velocity of the input makes the pressure loss increasing with parabola trend, diameter of holes affects little about pressure loss of the muffler. Otherwise, the holes on the perforated pipes make the air flow gently and meanly, which decreases the air impact to the wall and pipes in the muffler. A practical perforated muffler is used to illustrate the available of this method for pressure loss computation, and the comparison shows that the computation results with the method of CFD has reference value for muffler design. 展开更多
关键词 Perforated muffler Pressure loss computational fluid dynamics (CFD) Porosity flow velocity
下载PDF
Computation of flow through the oesophagogastric junction 被引量:2
2
作者 Barry P McMahon Karl D Odie +1 位作者 Kenneth W Moloney Hans Gregersen 《World Journal of Gastroenterology》 SCIE CAS CSCD 2007年第9期1360-1364,共5页
Whilst methods exist to indirectly measure the effects of increased flow or gastro-oesophageal refluxing, they cannot quantitatively measure the amount of acid travelling back up into the oesophagus during reflux, nor... Whilst methods exist to indirectly measure the effects of increased flow or gastro-oesophageal refluxing, they cannot quantitatively measure the amount of acid travelling back up into the oesophagus during reflux, nor can they indicate the flow rate through the oesophagogastric junction (OGJ). Since OGJ dysfunction affects flow it seems most appropriate to describe the geometry of the OGJ and its effect on the flow. A device known as the functional lumen imaging probe (FLIP) has been shown to reliably measure the geometry of and pressure changes in the OGJ. FLIP cannot directly measure flow but the data gathered from the probe can be used to model flow through the junction by using computational flow dynamics (CFD). CFD uses a set of equations known as the Navier-Stokes equations to predict flow patterns and is a technique widely used in engineering. These equations are complex and require appropriate assumptions to provide simplifications before useful data can be obtained. With the assumption that the cross-sectional areas obtained via FLIP are circular, the radii of these circles can be obtained. A cubic interpolation scheme can then be applied to give a high-resolution geometry for the OGJ. In the case of modelling a reflux scenario, it can be seen that at the narrowest section a jet of fluid squirts into the oesophagus at a higher velocity than the fluid surrounding it. This jet has a maximum velocity of almost 2 ms-1 that occurs where the OGJ is at its narrowest. This simple prediction of acid ‘squirting’ into the oesophagusillustrates how the use of numerical methods can be used to develop a better understanding of the OGJ. This initial work using CFD shows some considerable promise for the future. 展开更多
关键词 computational flow dynamics model OESOPHAGUS
下载PDF
Numerical modelling of flow and transport in rough fractures 被引量:2
3
作者 Scott Briggs Bryan W.Karney Brent E.Sleep 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2014年第6期535-545,共11页
Simulation of flow and transport through rough walled rock fractures is investigated using the latticeBoltzmann method (LBM) and random walk (RW), respectively. The numerical implementation isdeveloped and validat... Simulation of flow and transport through rough walled rock fractures is investigated using the latticeBoltzmann method (LBM) and random walk (RW), respectively. The numerical implementation isdeveloped and validated on general purpose graphic processing units (GPGPUs). Both the LBM and RWmethod are well suited to parallel implementation on GPGPUs because they require only next-neighbourcommunication and thus can reduce expenses. The LBM model is an order of magnitude faster onGPGPUs than published results for LBM simulations run on modern CPUs. The fluid model is verified forparallel plate flow, backward facing step and single fracture flow; and the RWmodel is verified for pointsourcediffusion, Taylor-Aris dispersion and breakthrough behaviour in a single fracture. Both algorithmsplace limitations on the discrete displacement of fluid or particle transport per time step to minimise thenumerical error that must be considered during implementation. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved. 展开更多
关键词 Hydrogeology Fracture flow Solute transport computational fluid dynamics Lattice Boltzmann method(LBM) Random walk(RW)
下载PDF
Numerical simulation on rotordynamic characteristics of annular seal under uniform and non-uniform flows 被引量:4
4
作者 吴大转 姜新阔 +2 位作者 初宁 武鹏 王乐勤 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第8期1889-1897,共9页
Currently, the flow field of annular seals disturbed by the circular whirl motion of rotors is usually solved using computational fluid dynamics(CFD) to evaluate the five rotordynamic coefficients. The simulations are... Currently, the flow field of annular seals disturbed by the circular whirl motion of rotors is usually solved using computational fluid dynamics(CFD) to evaluate the five rotordynamic coefficients. The simulations are based on the traditional quasi-steady method. In this work, an improved quasi-steady method along with the transient method was presented to compute the rotordynamic coefficients of a long seal. By comparisons with experimental data, the shortcomings of quasi-steady methods have been identified. Then, the effects of non-uniform incoming flow on seal dynamic coefficients were studied by transient simulations. Results indicate that the long seal has large cross stiffness k and direct mass M which are not good for rotor stability, while the transient method is more suitable for the long seal for its excellent performance in predicting M. When the incoming flow is non-uniform, the stiffness coefficients vary with the eccentric directions. Based on the rotordynamic coefficients under uniform incoming flow, the linearized fluid force formulas, which can consider the effects of non-uniform incoming flow, have been presented and can well explain the varying-stiffness phenomenon. 展开更多
关键词 long pump seal rotordynamic coefficients transient computational fluid dynamics(CFD) dynamic mesh non-uniform incoming flow
下载PDF
Computational fluid dynamic simulations on liquid film behaviors at flooding in an inclined pipe
5
作者 陈建业 唐媛 +3 位作者 张伟 王宇辰 邱利民 张小斌 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第9期1460-1468,共9页
The complex liquid film behaviors at flooding in an inclined pipe were investigated with computational fluid dynamic(CFD) approaches. The liquid film behaviors included the dynamic wave characteristics before flooding... The complex liquid film behaviors at flooding in an inclined pipe were investigated with computational fluid dynamic(CFD) approaches. The liquid film behaviors included the dynamic wave characteristics before flooding and the transition of flow pattern when flooding happened. The influences of the surface tension and liquid viscosity were specially analyzed. Comparisons of the calculated velocity at the onset of flooding with the available experimental results showed a good agreement. The calculations verify that the fluctuation frequency and the liquid film thickness are almost unaffected by the superficial gas velocity until the flooding is triggered due to the Kelvin–Helmholtz instability. When flooding triggered at the superficial liquid velocity larger than0.15 m·s-1, the interfacial wave developed to slug flow, while it developed to entrainment flow when it was smaller than 0.08 m·s-1. The interfacial waves were more easily torn into tiny droplets with smaller surface tension, eventually evolving into the mist flow. When the liquid viscosity increases, the liquid film has a thicker holdup with more intensive fluctuations, and more likely developed to the slug flow. 展开更多
关键词 Two phase flow Flooding Countercurrent flow limitation computational fluid dynamic Liquid film Inclined pipe
下载PDF
Analysis of gas-solid flow and shaft-injected gas distribution in an oxygen blast furnace using a discrete element method and computational fluid dynamics coupled model 被引量:3
6
作者 Zeshang Dong Jingsong Wang +2 位作者 Haibin Zuo Xuefeng She Qingguo Xue 《Particuology》 SCIE EI CAS CSCD 2017年第3期63-72,共10页
lronmaking using an oxygen blast furnace is an attractive approach for reducing energy consumption in the iron and steel industry. This paper presents a numerical study of gas-solid flow in an oxygen blast fur- nace b... lronmaking using an oxygen blast furnace is an attractive approach for reducing energy consumption in the iron and steel industry. This paper presents a numerical study of gas-solid flow in an oxygen blast fur- nace by coupling the discrete element method with computational fluid dynamics. The model reliability was verified by previous experimental results. The influences of particle diameter, shaft tuyere size, and specific ratio (X) of shaft-injected gas (51G) flowrate to total gas flowrate on the SIC penetration behavior and pressure field in the furnace were investigated. The results showed that gas penetration capacity in the furnace gradually decreased as the particle diameter decreased from 100 to 40 mm. Decreasing particle diameter and increasing shaft tuyere size both slightly increased the SIG concentration near the furnace wall but decreased it at the furnace center. The value of X has a significant impact on the SIG distribution. According to the pressure fields obtained under different conditions, the key factor affecting SIG penetration depth is the pressure difference between the upper and lower levels of the shaft tuyere. If the pressure difference is small, the SIG can easily penetrate to the furnace center. 展开更多
关键词 Oxygen blast furnace Discrete element method computational fluid dynamics Shaft gas injection Gas-solid flow Pressure field
原文传递
CFD study: Effect of pulsating flow on gas-solid hydrodynamics in FCC riser 被引量:5
7
作者 Milinkumr T. Shah Ranjeet P. Utikar Vishnu K. Pareek 《Particuology》 SCIE EI CAS CSCD 2017年第2期25-34,共10页
Gas–solid flow in a fluid catalytic cracking (FCC) riser exhibits poor mixing in the form of a core–annulus flow pattern and a dense bottom/dilute top distribution of solids. To enhance gas–solid mixing, studies ... Gas–solid flow in a fluid catalytic cracking (FCC) riser exhibits poor mixing in the form of a core–annulus flow pattern and a dense bottom/dilute top distribution of solids. To enhance gas–solid mixing, studies on dense fluidized beds have suggested using a pulsating flow of gas. The present study investigates the effect of pulsating flow on gas–solid hydrodynamics inside the FCC riser employing computational fluid dynamics. Two flow conditions are investigated: a cold flow of air-FCC catalyst in a pilot-scale riser and a reactive flow in an industrial-scale FCC riser. In the cold-flow riser, pulsating flows cause the slug flow of solids and thus increase the average solid accumulation in the flow domain and solid segregation towards the wall. In the industrial FCC riser, pulsating flows produce radial profiles that are more homogeneous. Pulsating flows further improve the conversion and yield in the initial few metres of height. At 7 m, the conversion from pulsating flow is 59%, compared with 44% in without pulsating flow. The results and analysis presented here will help optimize flow conditions in the circulating fluidized bed riser, in not only FCC but also applications such as fast pyrolysis and combustion. 展开更多
关键词 Fluid catalytic cracking RiserPulsating flow computational fluid dynamics
原文传递
Computational fluid dynamic modeling of gas flow characteristics of the high-power CW CO_2 laser 被引量:1
8
作者 黄鸿雁 王又青 《Chinese Optics Letters》 SCIE EI CAS CSCD 2011年第1期60-63,共4页
To increase the photoelectronic conversion efficiency of the single discharge tube and to meet the requirements of the laser cutting system, optimization of the discharge tube structure and gas flow field is necessary... To increase the photoelectronic conversion efficiency of the single discharge tube and to meet the requirements of the laser cutting system, optimization of the discharge tube structure and gas flow field is necessary. We present a computational fluid dynamic model to predict the gas flow characteristics of high-power fast-axial flow CO2 laser. A set of differential equations is used to describe the operation of the laser. Gas flow characteristics, are calculated. The effects of gas velocity and turbulence intensity on discharge stability are studied. Computational results are compared with experimental values, and a good agreement is observed. The method presented and the results obtained can make the design process more efficient. 展开更多
关键词 flow computational fluid dynamic modeling of gas flow characteristics of the high-power CW CO2 laser CO HIGH
原文传递
Numerical simulation of a dense solid particle flow inside a cyclone separator using the hybrid Euler-Lagrange approach 被引量:14
9
作者 Pawel Kozolub Adam Klimanek +1 位作者 Ryszard A. Bialecki Wojciech P. Adamczyk 《Particuology》 SCIE EI CAS CSCD 2017年第2期170-180,共11页
This paper presents a numerical simulation of the flow inside a cyclone separator at high particle loads. The gas and gas–particle flows were analyzed using a commercial computational fluid dynamics code. The turbule... This paper presents a numerical simulation of the flow inside a cyclone separator at high particle loads. The gas and gas–particle flows were analyzed using a commercial computational fluid dynamics code. The turbulence effects inside the separator were modeled using the Reynolds stress model. The two phase gas–solid particles flow was modeled using a hybrid Euler–Lagrange approach, which accounts for the four-way coupling between phases. The simulations were performed for three inlet velocities of the gaseous phase and several cyclone mass particle loadings. Moreover, the influences of several submodel parameters on the calculated results were investigated. The obtained results were compared against experimental data collected at the in-house experimental rig. The cyclone pressure drop evaluated numerically underpredicts the measured values. The possible reason of this discrepancies was disused. 展开更多
关键词 Cyclone separator Two-phase flow Solid particle transport computational fluid dynamics Hybrid Euler-Lagrange
原文传递
Modeling and simulation of chemically reacting flows in gas-solid catalytic and non-catalytic processes 被引量:5
10
作者 Changning Wu Binhang Yan Yong Jin Yi Cheng 《Particuology》 SCIE EI CAS CSCD 2010年第6期525-530,共6页
This paper gives an overview of the recent development of modeling and simulation of chemically react- ing flows in gas-solid catalytic and non-catalytic processes. General methodology has been focused on the Eulerian... This paper gives an overview of the recent development of modeling and simulation of chemically react- ing flows in gas-solid catalytic and non-catalytic processes. General methodology has been focused on the Eulerian-Lagrangian description of particulate flows, where the particles behave as the catalysts or the reactant materials. For the strong interaction between the transport phenomena (i.e., momentum, heat and mass transfer) and the chemical reactions at the particle scale, a cross-scale modeling approach, i.e., CFD-DEM or CFD-DPM, is established for describing a wide variety of complex reacting flows in multiphase reactors, Representative processes, including fluid catalytic cracking (FCC), catalytic conversion of syngas to methane, and coal pyrolysis to acetylene in thermal plasma, are chosen as case studies to demonstrate the unique advantages of the theoretical scheme based on the integrated particle-scale information with clear physical meanings, This type of modeling approach provides a solid basis for understanding the multiphase reacting flow problems in general. 展开更多
关键词 Gas-solid chemically reacting flow Cross-scale modeling and simulation Eulerian-Lagrangian scheme computational fluid dynamics (CFD) Discrete element method (DEM) Discrete phase model (DPM)
原文传递
Microarchitectural mimicking of stroma-induced vasculature compression in pancreatic tumors using a 3D engineered model 被引量:1
11
作者 Marcel Alexander Heinrich Irene Uboldi +5 位作者 Praneeth Reddy Kuninty Marc J.K.Ankone Joop van Baarlen Yu Shrike Zhang Kartik Jain Jai Prakash 《Bioactive Materials》 SCIE CSCD 2023年第4期18-33,共16页
Fibrotic tumors,such as pancreatic ductal adenocarcinoma(PDAC),are characterized for high desmoplastic reaction,which results in high intra-tumoral solid stress leading to the compression of blood vessels.These microa... Fibrotic tumors,such as pancreatic ductal adenocarcinoma(PDAC),are characterized for high desmoplastic reaction,which results in high intra-tumoral solid stress leading to the compression of blood vessels.These microarchitectural alterations cause loss of blood flow and poor intra-tumoral delivery of therapeutics.Currently,there is a lack of relevant in vitro models capable of replicating these mechanical characteristics and to test anti-desmoplastic compounds.Here,a multi-layered vascularized 3D PDAC model consisting of primary human pancreatic stellate cells(PSCs)embedded in collagen/fibrinogen(Col/Fib),mimicking tumor tissue within adjunct healthy tissue,is presented to study the fibrosis-induced compression of vasculature in PDAC.It is demonstrated how the mechanical and biological stimulation induce PSC activation,extracellular matrix production and eventually vessel compression.The clinical relevance is confirmed by correlating with patient transcriptomic data.Furthermore,the effects of gradual vessel compression on the fluid dynamics occurring within the channel is evaluated in silico.Finally,it is demonstrated how cancer-associated fibroblast(CAF)-modulatory therapeutics can inhibit the cell-mediated compression of blood vessels in PDAC in vitro,in silico and in vivo.It is envisioned that this 3D model is used to improve the understanding of mechanical characteristics in tumors and for evaluating novel anti-desmoplastic therapeutics. 展开更多
关键词 Pancreatic ductal adenocarcinoma Cancer-associated fibroblasts COLLAGEN FIBRINOGEN computational flow dynamics 3D in vitro model
原文传递
Compact fluidized bed sorber for CO_2 capture 被引量:2
12
作者 Parinya Khongprom Dimitri Gidaspow 《Particuology》 SCIE EI CAS CSCD 2010年第6期531-535,共5页
Multiphase CFD is used to design a compact fluidized bed sorber for CO2 removal from flue gases using sodium or potassium carbonate pellets. The sorber sizes are much smaller than commercial amine absorbers and smalle... Multiphase CFD is used to design a compact fluidized bed sorber for CO2 removal from flue gases using sodium or potassium carbonate pellets. The sorber sizes are much smaller than commercial amine absorbers and smaller than other proposed dry adsorbers. The size reduction is due to the elimination of dilute regions that cause bypassing. With proper solids feeding we eliminated the usual core-annular regime found in circulating fluidized beds. 展开更多
关键词 Separation science Flue gas Carbon capture Multiphase flow computational fluid dynamics
原文传递
Cyclone separation in a supercritical water circulating fluidized bed reactor for coallbiomass gasification: Structural design and numerical analysis 被引量:6
13
作者 Guoxing Li Youjun Lu 《Particuology》 SCIE EI CAS CSCD 2018年第4期55-67,共13页
A new concept of a supercritical water (SCW) circulating fiuidized bed reactor is proposed to produce hydrogen from coal/biomass gasification. The cyclone is a key component of the reactor system, in this paper, cyc... A new concept of a supercritical water (SCW) circulating fiuidized bed reactor is proposed to produce hydrogen from coal/biomass gasification. The cyclone is a key component of the reactor system, in this paper, cyclones with a single circular inlet (SCI) or a double circular inlet (DCI) were designed to adapt to the supercritical conditions. We evaluated the separation performance of the two cyclones using numerical simulations. A three-dimensional Reynolds stress model was used to simulate the turbulent flow of the fluid, and a stochastic Lagrangian model was used to simulate the particle motion. The flow fields of both cyclones were three-dimensionally unsteady and similar to those of traditional gas-solid cyclones. Secondary circulation phenomena were discovered and their influence on particle separation was estimated. Analyzing the distribution of the turbulence kinetic energy revealed that the most intensive turbulence existed in the zone near the vortex finder while the flow in the central part was relatively stable. The particle concentration distribution was non-uniform because of centrifugal forces. The distribution area can be divided into three parts according to the motion of the particles. In addition, the separation efficiency of both cyclones increased with the inlet SCaN velocity. Because of its perturbance flow, the DCI separator had higher separation efficiency than the SCI separator under comparable simulations. However, this was at the expense of a higher pressure drop across the cyclone. 展开更多
关键词 CycloneStructural design Supercritical water-solid flow Separation performance Circulating fluidized bed computational fluid dynamics
原文传递
Investigation of particle-wall interaction in a pseudo-2D fluidized bed using CFD-DEM simulations 被引量:5
14
作者 Tingwen Li Yongmin Zhang Fernando Hernandez-Jimenez 《Particuology》 SCIE EI CAS CSCD 2016年第2期10-22,共13页
We report on discrete element method simulations of a pseudo-two-dimensional (pseudo-2D) fluidized bed to investigate particle-wall interactions. Detailed information on macroscopic flow field variables, including s... We report on discrete element method simulations of a pseudo-two-dimensional (pseudo-2D) fluidized bed to investigate particle-wall interactions. Detailed information on macroscopic flow field variables, including solids pressure, granular temperature, and normal and tangential wall stresses are analyzed. The normal wall stress differs from the solids pressure because of the strong anisotropic flow behavior in the pseudo-2D system. A simple linear relationship exists between normal wall stress and solids pressure. In addition, an effective friction coefficient can be derived to characterize particle-wall flow interaction after evaluating the normal and tangential wall stresses. The effects of inter-particle and particle-wall friction coefficients are evaluated. Strong anisotropic flow behavior in the pseudo-2D system needs to be considered to validate the two-fluid model where the boundary condition is usually developed based on an isotropic assumption. The conclusion has been confirmed by simulation with different particle stiffnesses. Assumptions in the newly developed model for 2D simulation are further examined against the discrete element method simulation. 展开更多
关键词 Gas-solid tlow Fluidized bed computational fluid dynamics Discrete element method Particle-wall interaction Two-dimensional flow
原文传递
Landmarks in the application of electrical tomography in particle science and technology 被引量:4
15
作者 Richard A.Williams 《Particuology》 SCIE EI CAS CSCD 2010年第6期493-497,共5页
Selected milestones in the development and use of electrical tomography in powder conveying, slurry processing and multi-phase flow are highlighted. The ability to map concentration in opaque mixtures under process-re... Selected milestones in the development and use of electrical tomography in powder conveying, slurry processing and multi-phase flow are highlighted. The ability to map concentration in opaque mixtures under process-realistic conditions was a major innovation for the method and has had far reaching implications. Subsequent developments have enabled velocity information to be abstracted resulting in the ability to measure component flux and motion. 展开更多
关键词 computational fluid dynamics Fault condition and maloperation flow measurement flow regime identification Particle concentration Process control Process safety
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部