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Computational fluid dynamics modelling of gas jets impinging onto liquid pools

APPLIED mathematical modelling 2006年第11期30卷 1472-1484页

作者： Nguyen, Anh V. Evans, Geoffrey M. Univ Newcastle Sch Engn Callaghan NSW 2308 Australia

Gas jets impinging onto a gas-liquid interface of a liquid pool are studied using computational fluid dynamics modelling, which aims to obtain a better understanding of the behaviour of the gas jets used metallurgical engineering industry. The gas and liquid flows are modelled using the volume of fluid technique. The governing equations are formulated using the density and viscosity of the "gas-liquid mixture", which are described in terms of the phase volume fraction. Reynolds averaging is applied to yield a set of Reynolds-averaged conservation equations for the mass and momentum, and the k-epsilon turbulence model. The deformation of the gas-liquid interface is modelled by the pressure jump across the interface via the Young-Laplace equation. The governing equations in the axisymmetric cylindrical coordinates are solved using the commercial CFD code, FLUENT. The computed results are compared with experimental and theoretical data reported in the literature. The CFD modelling allows the simultaneous evaluation of the gas flow field, the free liquid surface and the bulk liquid flow, and provides useful insight to the highly complex, and industrially significant flows in the jetting system. (c) 2006 Elsevier Inc. All rights reserved.

关键词： impinging gas jets liquid pool velocity field free surface profile

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modelling and simulation of fluid power systems in object-oriented programming environment

Modelling and simulation of fluid power systems in object-or...

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8th Biennial ASME conference on engineering Systems Design and Analysis

作者： Grossschmidt, Gunnar Harf, Mait Sallaste, Taavi Tallinn Univ Technol Inst Machinery EE-19086 Tallinn Estonia

ISBN: (纸本)9780791842492

The paper deals with principles of computer modelling and simulation of behaviour of fluid power systems in object-oriented programming environment. The approach is based on using multi-pole models and signal-flow graphs of functional elements, that enables methodical, graphical representation of mathematical models of large and complicated chain systems. In this way we can be convinced in the correct composing of models. A high-level programming environment NUT is used as a tool for building modelling and simulation systems. Several modelling and simulation systems have been developed using approach described above. Different simulation tasks have been solved on these modelling systems. Methodology described in the paper has several advantages and novelties.

关键词： modelling and simulation load-sensing fluid power systems multi-pole models object-oriented programming tools

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3D bone tissue growth in hollow fibre membrane bioreactor: implications of various process parameters on tissue nutrition

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INTERNATIONAL JOURNAL OF ARTIFICIAL ORGANS 2006年第9期29卷 841-851页

作者： Abdullah, N. S. Das, D. B. Ye, H. Cui, Z. F. Univ Oxford Dept Engn Sci Oxford OX1 3PJ England

New experimental evidence shows that hollow fibre membrane bioreactor (HFMB) may be applied to grow bulky bone tissues which may then be implanted into patients to repair skeletal defects. To design effective bone tissue engineering protocols, it is necessary to determine the quantitative relationships between the cell environment and tissue behaviour in HFMBs and their relationship with nutrient supply. It is also necessary to determine under what conditions nutritional limitations may occur and, hence, may cause cell death. These require that the appropriate bioreactor conditions for generating neotissues, and the nutrient transfer behaviour and chemical reaction during cell growth and extracellular matrix formation are studied thoroughly. In this paper, we aim to use an existing mathematical framework to analyse the influence of various relevant parameters on nutrient supply for bone tissue growth in HFMB. We adopt the well-known Krogh cylinder approximation of the HFMB. The model parameters ( e. g., cell metabolic rates) and operating conditions for the mathematical model have been obtained from, or correspond to, in-house experiments with the exception of a few variables which have been taken from the literature. The framework is then used to study oxygen and glucose transport behaviour in the HFMB. Influence of a number of important process parameters, e. g., reaction kinetics, cell density, inlet concentration of nutrients, etc, on the nutrient distributions have been systematically analysed. The work presented in this paper provides insights on unfavourable system designs and specifications which may be avoided to prevent mass transfer limitations for growing bone tissues in HFMB.

关键词： bone tissue engineering hollow fibre membrane bioreactor bulky bone tissues mathematical modelling Krogh cylinder geometry

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Optimization of choice ocalization of exposure during extremely-high frequencies therapy with mathematical modelling

Optimization of choice ocalization of exposure during extrem...

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International conference on Actual Problems of Electrons Devices engineering, APEDE 2006

作者： Chesnokov, I.A. Lyapina, E.P. Anisimov, Ya.E. Bushuev, N.A. Murashev, E.P. Kornauhov, A.V. Anisimov, S.I. Federal State Unitary Enterprise SPE Almaz Saratov Russia N.I. Lobachevsky State University of Nizhni Novgorod

The mathematical model of interaction the energy meridians of human organism for optimization of influence during doing extremely-high frequencies therapy is presented. This mathematical model made with using mathemat... 详细信息

ISBN: (纸本)1424402476

关键词： Automation

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modelling and simulation of the TLR4 pathway with coloured Petri Nets

Modelling and simulation of the TLR4 pathway with coloured P...

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28th Annual International conference of the IEEE-engineering-in-Medicine-and-Biology-Society

作者： Taeubner, C. Mathiak, B. Kupfer, A. Fleischer, N. Eckstein, S. Tech Univ Carolo Wilhelmina Braunschweig Inst Informat Syst D-3300 Braunschweig Germany

ISBN: (纸本)9781424400324

This paper demonstrates the first steps of an automation process to develop models of signal transduction path-ways using discrete modelling languages. The whole approach consists or modelling, validation, animation, linking databases to simulation tools and also the qualitative analysis of the data. In this paper, we detail the modelling and simulation of the TLR4 pathway with a Coloured Petri Net simulation tool and the validation of this model against the semantic and mechanistic map from a biological database. These graphical maps contain all necessary reactions as a figure. We start with an UML class diagram to understand the static structure of molecules involved in the TLR4 pathway. Afterwards we model and simulate each "pathway step reaction" - one after another - to get the behaviour of the final system. The result is a model of the pathway which can be used in simulations, derived solely from basic chemical reactions in the database. Also, it is a lesson on critical points where human decision-making is needed, because not all the required information is stored directly in the database.

关键词： Signal processing

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modelling of interactive populations of disperse systems

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CHEMICAL engineering SCIENCE 2006年第1期61卷 54-62页

作者： Lakatos, BG Mihálykó, C Blickle, T Univ Veszprem Dept Proc Engn H-8200 Veszprem Hungary Univ Veszprem Dept Math & Comp H-8200 Veszprem Hungary Univ Veszprem Inst Chem & Proc Engn H-8200 Veszprem Hungary

The paper presents a general mathematical model for disperse systems in which direct interactions between particles are taken into consideration. The model is formulated in terms of transition measures, introduced on the basis of conditional Markov processes. The population balance equation, describing the behaviour of interactive populations, is developed in a general form of continuous and discontinuous terms. Moment equations are presented and analysed for the axial dispersion model with interparticle exchange processes of heat and mass. The applicability of the model is illustrated by applying it for describing a process of heating particles by gas with interparticle heat transfer, and a mass exchange process between fluid particles. (c) 2005 Elsevier Ltd. All rights reserved.

关键词： population balance Markov process interactive population measure interparticle heat and mass transfer moment equations

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mathematical modelling of particle formation in combustion processes

Mathematical modelling of particle formation in combustion p...

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8th Biennial ASME conference on engineering Systems Design and Analysis

作者： Zucca, Alessandro Marchisio, Daniele L. Barresi, Antonello A. Baldi, Giancarlo Politecn Torino Dip Sci Mat & Ingn Chim I-10129 Turin Italy

ISBN: (纸本)9780791842515

In recent years the problem of studying particle formation and evolution in turbulent flames has become increasingly important, for both environmental and technological reasons. Information on particle size and morphology is often required, since these characteristics largely influence the effects of particulate matter on human health and global climate in the case of soot. A mathematical model able to describe the evolution of these particulate systems must solve the population balance equation within a Computational Fluid Dynamics (CFD) code that predicts the temperature, composition and velocity fields of the flame. In this work, the recently proposed Direct Quadrature Method of Moments (DQMOM) is applied to the study of soot formation in turbulent non-premixed flames. The model takes into account nucleation, molecular growth, oxidation and aggregation of soot particles;simplified kinetic rates are employed, while velocity and scalar fields are computed by simulations based on the solution of the Reynolds Averaged Navier Stokes (RANS) equations. Different population balance formulations are implemented and compared and results show that DQMOM is a suitable modelling tool;comparison of predictions with experimental data shows that the model accurately describes the morphological properties of soot aggregates.

关键词： Combustion

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3D bone tissue growth in hollow fibre membrane bioreactor: implications of various process parameters on tissue nutrition

3D bone tissue growth in hollow fibre membrane bioreactor: i...

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4th conference on engineering with Membranes - Medical and Biological Applications

作者： Abdullah, N. S. Das, D. B. Ye, H. Cui, Z. F. Univ Oxford Dept Engn Sci Oxford OX1 3PJ England

关键词： bone tissue engineering hollow fibre membrane bioreactor bulky bone tissues mathematical modelling Krogh cylinder geometry

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Application of MML to motor skills acquisition

Application of MML to motor skills acquisition

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CIMCA 2006: International conference on Computational Intelligence for modelling, Control and Automation, Jointly with IAWTIC 2006: International conference on Intelligent Agents Web Technologies and International Commerce

作者： Sun, Chao Naghdy, Fazel Stirling, David School of Electrical Computer and Telecommunications Engineering University of Wollongong NSW Australia

ISBN: (纸本)0769527310

Study on modeling human psychomotor behaviour based on tracked motion data is reported. The motion data is acquired through various integrated inertial sensors, and represented as Euler angles and accelerations. The Minimum Message Length (MML) algorithm is used to identify frames of intrinsic segmentations and to acquire a classification basis for unsupervised machine learning. The classification model can ultimately be deployed in recognizing certain skilled behaviors. The prior results are analyzed as FSMs ' (Finite State Machines) to extract the potential rules underlying behaviors. The progress made so far and plan for further work is reported. © 2006 IEEE.

关键词： human computer interaction

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Investigation of laminar flow in a stirred vessel at low Reynolds numbers

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CHEMICAL engineering SCIENCE 2006年第9期61卷 2762-2770页

作者： Rice, M Hall, J Papadakis, G Yianneskis, M Kings Coll London Dept Mech Engn ECLAT London WC2R 2LS England

Many mixing applications involve viscous fluids and laminar flows where the detailed as well as overall flow structures are important. In order to understand the fluid dynamic characteristics of low Re laminar flows in mixing vessels, the flow induced by a Rushton impeller for three Re namely, 1, 10 and 28, was studied both experimentally and computationally. It was found that for the highest Re, the flow exhibited the familiar outward pumping action associated with radial impellers under turbulent flow conditions. However, as the Re decreases, the net radial flow during one impeller revolution was reduced and for the lowest Re a reciprocating motion with negligible net pumping was observed. This behaviour has not been reported in the literature in the past and represents a highly undesirable flow pattern from the standpoint of effective mixing. The CFD results successfully reproduced this behaviour. In order to elucidate the physical mechanism responsible for the observed flow pattern, the forces acting on a fluid element in the radial direction were analysed. The analysis indicated that for the lowest Re, the material derivative of radial velocity near the blade tip is small thus a balance exists between pressure and viscous forces;the defining characteristic of creeping flow. The velocity and pressure forces are in phase because the velocity is driven by the pressure field generated by the rotation of the impeller. Based on these findings, a simplified analytic model of the flow was developed that gives a good qualitative as well as quantitative representation of the flow. (c) 2005 Elsevier Ltd. All rights reserved.

关键词： mathematical modelling fluid mechanics laminar flow simulation transport process

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