Global Summit and Expo on Fluid Dynamics & Aerodynamics August 15-16, 2016 London, UK

Biography:

Alex Neves Junior has completed his PhD from Federal University of Rio de Janeiro. At moment, he is Adjunct Professor at the Federal University of Mato Grosso and Member of the Brazilian Association of Thermal Analysis. He was invited to participate in the book "Who is Who in Thermal Analysis and Calorimetry" by the Springer Publishing Company. He is Reviewer of the Journal of Thermal Analysis and Calorimetry and Building Construction and Materials. Two patents are requested by him: “Non-Conventional Thermogravimetry System in Controlled Chamber” and “New System of Non-Conventional Differential Thermal Analysis in Controlled Chamber”.

Abstract:

In a previous work, the authors achieved the best environmental conditions to capture CO₂ in a high initial strength and sulfate-resistant Portland cement pastes after 24 hours of carbonation. However the samples that were totally carbonated with the consumption of all Ca(OH)₂ had their mechanical properties affected. The samples presented a high initial water to cement ratio in the moment of treatment and considering that they were treated with carbon dioxide at early stages with a high initial porosity in a low relative humidity ambient, the flow of the fluids to the inner parts to outer parts of the samples, affected the distribution and the amount of the hydrated and carbonated products formed. The aim of this work was to analyze by thermogravimetry (TG), derivative thermogravimetry (DTG) and compressive strength test, considering different times of carbonation, the distribution of the hydrated and carbonated products formed in the profile of the samples and the relationship with the mechanical properties. 

Biography:

Iurii Sharikov has completed his PhD from Leningrad Technological Institute, Leningrad, USSR and received his Grade of Doctor of Science in Mendeleev Chemical and Technological Institute Moscow, USSR. In 1976, he received the title of Professor in specialty of Chemical Engineering. He is Professor of the Mining University, St. Petersburg. He is focusing on researches in field of mathematical modeling and optimal control. He is author of more than 150 papers in reputed journals and serves as an Editorial Board Member of repute.

Abstract:

Mathematical modeling of processes in the chemical and metallurgical industries is widely used nowadays to create industrial production on the basis of experimental studies of the processes in the laboratory. A common method for creating mathematical models of processes is the synthesis of heat and mass transfer equations on the basis of dynamics equations of moving phases and source terms that express the kinetics of chemical reactions and phase transitions and thermal effects. To investigate the kinetics of chemical reactions in multistage polyphase systems, it is very effective to use the heat flux calorimetry in conjunction with the analysis of the composition in characteristic points in the heat generation curves. Using this technique, we have conducted studies of the kinetics of chemical reactions in the process of producing cement clinker and in the preparation of alumina in tubular rotating kilns, as well as processes for the modification of epoxy resins to enhance their functionality. On the basis of experimental data, the parameters of kinetic models were determined by solving the inverse kinetic problems and verified the adequacy of the obtained models. Created on the basis of these kinetics data, mathematical models of reactor unit have been used for the optimization of processes in industrial conditions. Optimization tasks have been solved using the method of nonlinear programming in the environment of a specialized software package for the development and analysis of mathematical models of reactor units. Special structure of control system has been developed for the implementation of discussed processes. 

Biography:

Asher Yahalom is a Professor in the Faculty of Engineering at Ariel University and the Academic Director of the Free Electron Laser User Center which is located within the university center campus. He received BSc, MSc and PhD degrees in Mathematics and Physics from the Hebrew University in Jerusalem, Israel in 1990, 1991 and 1996 respectively. He was a Postdoctoral Fellow in 1998 at the Department of Electrical Engineering of Tel-Aviv University, Israel. He was a Visiting Fellow at the University of Cambridge, UK during the years 2005-2006, 2008 and 2012. 

Abstract:

In previous papers, we have described how by minimizing the fluid action numerically one can obtain a solution of the fluid steady state equations. The action which was used was the four function action of Seliger & Whitham. In a recent paper, Yahalom & Lynden-Bell described how one can improve upon previous art by reducing the number of variables in the action. Three independent functions variational formalism for stationary and non-stationary barotropic flows were introduced. This is less than the four variables which appear in the standard equations of fluid dynamics which are the velocity field  and the density ρ. Here we suggest a finite element approach to solve the reduced equations.

Biography:

Zhengfang Qian has completed his Master’s degree in 2000. He is a Professor at Naval Academy of Armament. His major is Marine Propeller. He has published more than 20 papers in reputed journals and has been serving as an Editorial Board Member of repute.

Abstract:

In the paper, the research on sheet cavitation numerical predicted and estimation of tip vortex cavitation inception of ducted propeller with pre-swirl stator behind underwater vehicle was carried out. Firstly, the sheet cavitation shape of ducted propeller with pre-swirl stator was numerically simulated using a hybrid mesh based on RANS (Reynolds Averaged Navier Stokes) solver. A Singhal cavitation model based on transport equation was coupled in the RANS solver. The predicted sheet cavitation shapes were in good agreement with experimental observation. The overall results suggest that the present approach on predicting sheet cavitation shape of propeller behind underwater vehicle is practicable. Secondly, the wetted flow of ducted propeller with pre-swirl stator behind underwater vehicle was simulated, and the tip vortex cavitation inception was estimated based on the minimum pressure value on the propeller tip section. The results were also in good agreement with experimental results. It showed that the approach on estimation of tip vortex cavitation inception is feasible.

Biography:

Josep M Bergada completed his PhD in Mechanical Engineering in 1996 at Universitat Politecnica de Catalunya UPC-Spain, from the year 2000 to 2010 collaborated with Cardiff University UK, in evaluating the performance of piston pumps and valves, both used in the fluid power sector. From the year 2010 to 2014, he developed part of his research activities at TU-Berlin where he studied active flow control devices like fluidic actuators and synthetic jets. At the present, his research is related to Active Flow Control and his academic activities are based on lecturing Fluid Mechanics I and II at UPC. He has 26 years’ experience of lecturing at UPC. He published 12 papers at SCI journals, over 45 papers in conferences and two main books on Fluid Mechanics and Fluid Power. He is member of the editorial board of an SCI Journal

Abstract:

Flow control, whether passive or active, has a wide range of applications. Aircraft industry, for example, it is interested in using active flow control to modify lift and drag on aircraft wings. Car industry, is aiming to reduce vortex formation on the rear of cars/trucks to diminish drag and therefore reduce fuel consumption. Construction industry has traditionally used passive flow control to minimize or even suppress downstream undesirable vortices on bridges, buildings, pipes placed perpendicular to a flow, etc; the use of active flow control is also currently under study. Several methods have been so far tested to find out its efficiency, reliability and simplicity regarding the active flow control approach. The use of constant blowing, constant suction, periodic blowing and suction, involving devices like synthetic jets or fluidic actuators is nowadays being tested in many fields. Important parameters related to active flow control actuators are, the precise location of the actuation system, the fluid jet amplitude, the momentum coefficient and the jet frequency if pulsating flow is used. In the present paper, the effect of suction and blowing at different inclination angles, groove dimensions and location, as well as several velocity ratios have been evaluated via CFD on a NACA profile under turbulent conditions, Reynolds number 3*106, angle of attack 12o. The results obtained clarify which set of parameters is mend to be the optimum to maximize lift and minimize drag. Some of the results obtained are presented in the figures below.

Biography:

Eric Suraud is distinguished Professor of Physics at Toulouse University in France and Member of Institut Universitaire de France and of European Academy of Sciences and Academia Europaea. He also had several high level responsibilities in the administration of research in France. After a PhD in Paris and a 10 years of activity in nuclear physics, he turned towards electronic dynamics in the mid 1990’s. He has published more than 170 papers in peer review journals and 7 books. He has been invited to more than 130 international conferences and gave many seminars in laboratories all over the world.

Abstract:

Eric Suraud is distinguished Professor of Physics at Toulouse University in France and Member of Institut Universitaire de France and of European Academy of Sciences and Academia Europaea. He also had several high level responsibilities in the administration of research in France. After a PhD in Paris and a 10 years of activity in nuclear physics, he turned towards electronic dynamics in the mid 1990’s. He has published more than 170 papers in peer review journals and 7 books. He has been invited to more than 130 international conferences and gave many seminars in laboratories all over the world.

Biography:

Kaifu Ye has completed his Master’s in 1995. He is a famous Researcher in the Marine Engineering. He has published more than 15 papers in reputed journals and has been serving as an Editorial Board Member of repute.

Abstract:

As an important parameter of turbulence, the turbulence integral length scale has always been the hotspot of research. Nowadays, the turbulence integral length scale is obtained mostly by experiment. This paper proposed a numerical method: Compute unsteady flow field by LES, from which obtain fluctuation velocity and calculate the turbulence integral length scale based on velocity cross-correlation function. The three subgrid-scale models: DSL, WALE (wall-adapting local eddy viscosity model) and DKET, were analyzed in unsteady flow, time-average flow and turbulence integral length scale. The DSL turned out to have the highest precision. The DSL numerical method was used to predict the turbulence integral length scale of SUBOFF. The results showed that the peak bars of É… are near 20 and 90 degree according to the existence of horse-shoe vortexes of conning tower and stabilizers; the integral lengths at outside radius were lager than those at inside radius because of the diffusion of vortexes. This research can provide a reference for further understanding of low-frequency broadband noise and the establishment of the numerical method of anisotropic turbulence integral length.

Biography:

Jingwei Jiang has completed his Master’s degree in 2013. Currently, he is a PhD student in Naval Academy of Armament. His major is marine propeller design and fluid and structure interaction. He has published more than 10 papers in reputed journals

Abstract:

A numerical prediction method, considering fluid-structure interaction, has been developed to predict and analyze the hydrodynamic performance of submarine, which is based on CFD (Computational Fluid Dynamics) and FEM (Finite Element Modeling) technology. The flow is considered to be uncompressible and viscous. SST k-ω is chosen as the turbulence model for its good precision and efficient computational-time cost, and SIMPLE algorithm is used to solve the coupled equations of pressure and velocity. Meanwhile, FEM is utilized to compute the structure response of the hull according to the unsteady fluid pressure outside, which is gained from the results of CFD. The interaction effect between the fluid flow and the structure is considered as weak coupling. The deformation of the submarine hull is taken into consideration in every iterative procedure instead of after accomplishing the CFD computation, helping to reduce the design time and increase efficiency greatly. Resistance, stress-strain and natural frequency have been gained from this method. The method is validated by comparing the computational result with the engineering estimation data. The numerical prediction method proposed in this paper is effective, reliable and practical, which makes it a suitable tool for the design and analysis of submarine.

Biography:

Olga V Mitrofanova has completed her PhD from Moscow Engineering Physics Institute, Russia and obtained Doctor of Science degree from Russian Research Center, Kurchatov Institute, Moscow, Russia. She is Professor of National Research Nuclear University “MEPhI”, Leading Researcher of RRC at Kurchatov Institute, Chief Researcher of Institute of Metallurgy and Material Science (Russian Academy of Sciences). Fields of her research activity are hydrodynamics of complicated vortex and turbulent flows, simulation of heat and mass transfer in channels of nuclear power installations. She has published more than 170 papers.

Abstract:

The present report focuses on the problems of physical and mathematical modeling of large-scale vortex structures as special objects of study of fluid dynamics. The analysis of physical features and theoretical description of helical and swirl flows has been done. Physical and computational experiments to identify the mechanisms of appearance of large-scale vortex structures in channels of complex geometry under condition of the turbulent flows of conductive and neutral fluids have been carried out. The theoretical aspects concerning the modeling of the processes of vortex generation and accumulation of energy by large-scale vortex structures have been considered to predict accidents in engineering systems and natural disasters. It is shown that the topology of the stable form of helical-vortex formations has a structural similarity depending on the vorticity intensity of the fluid motion. This paper presents the results of studies on the solution of problems of the safety improving of power installations and the prevention of emergency modes arising from acoustic and resonant effects, interdependence of large-scale vortex motion with acoustic effects in hydro-mechanical systems and with magneto-hydrodynamic effects in conductive fluids, conditions of formation of large scale vortex and swirl flows in nuclear power installations (in particular, the phenomenon of spontaneous swirling of a flow and the generation of large-scale vortices in the collector systems of the fast neutron reactors), parameters of acoustic oscillations arising during the generation of stable vortex structures (to prevent the development of vibrations) and phenomena of acoustic cavitation and other mechanisms of mechanical energy transformation in high-speed vortex streams. The obtained results are intended both for engineering applications and for the development of simulation methods to predict some hazardous geophysical processes such as hurricanes, tornados, tsunami and changing the direction of ocean currents.

Biography:

V V Aristov has completed his PhD from Moscow Institute of Physics and Technology and Post-doctoral studies from Dorodnicyn Computing Centre of Russian Academy of Sciences where he defended his Dr.Sc. thesis. He is Head of Subdivision of Kinetic Theory of Gases in Dorodnicyn Computing Centre of Russian Academy of Sciences and Professor of Moscow Institute of Physics and Technology (State University). He has published more than 35 papers in reputed journals. 

Abstract:

New problems with nonequilibrium boundary conditions are formulated and solved on the basis of the Boltzmann and kinetic model equations. These simulations are stimulated by modern interest for understanding strong nonequilibrium processes in open systems. Some generalizations of spatially nonuniform relaxation problems for supersonic and subsonic boundary conditions are considered. Direct methods of solving kinetic equations are used. Anomalous stress and heat transport is obtained and analyzed. A known problem of heat conduction between two plates with different temperatures but with the nonequilibrium condition in one of them (namely, in the left boundary) is studied. Some restrictions were found under which the signs of heat flux and temperature gradients are the same. At the boundary the nonequilibrium ellipsoidal distribution function is accepted with different ratios of the transversal temperatures T_nl and longitudinal temperature T_xl (which is fixed). The heat flux q_x is constant and positive for all variants and the temperature gradients are also positive. Several experimental tests can be proposed to confirm the mentioned effects. The main problem is to create and maintain boundary nonequilibrium states. This could be resolved e.g. by means of the optic lattices or by means of the magnetic trap. One can discuss possible applications of these anomalous effects. A new problem with the “membrane-like” boundary conditions is formulated and solved. Due to accepting different boundary distributions in velocity space, it is possible to form different spatial distributions of macroscopic parameters. Regions with anomalous transport are obtained. Formulation of this problem for the kinetic equation including chemical reactions is also considered. Possible relations for biological oriented problems are discussed. 

Biography:

Ghalib Y Kahwaji completed his PhD in Mechanical Engineering from Colorado State University. He is working as Professor and Chair in Department of Mechanical and Industrial Engineering at RIT-Dubai. He joined RIT-Dubai as a Professor of thermo-fluids, air conditioning and renewable energy systems. Prior to joining RIT, he spent five years in industry and engineering consulting as the Head of MEP Design Department and Engineering Manager at Al-Gurg Consultants, Dubai and TRANSCO, Abu Dhabi where his work involved large scale water transmission systems and energy systems for high rise and industrial buildings in the UAE. Prior to moving to the UAE, he served as the Associate Dean for research and graduate programs and Chairman of the Department of Mechanical Engineering at the College of Engineering, University of Mosul from 2003 till 2006 and was as a Faculty of Mechanical Engineering since 1987. 

Abstract:

The freezing of water around finned and unfinned horizontal tubes inside an insulated tank is analyzed and numerically simulated. The coupled conduction-convection heat transfer with phase change moving interface is solved numerically using finite difference technique. Adaptive grid generation is performed by elliptic partial differential equations coupled with a proportional, iterative smoothing algorithm. The effect of density inversion with temperature on flow patterns is also considered. For validation, the present results are compared with experimental studies reported in the literature. The flow patterns are similar in both cases as there is one main vortex in the liquid region when there is no inversion in water density. The vortices of water existing before and after the inversion process are also similar. The inversion in density was found to disturb the flow patterns and the isothermal lines in the liquid region. The presence of fins complicates the local Nusselt Number distribution along the solid-liquid interface in comparison with the unfinned cylinder. The impact of natural convection on the rate of ice formation is limited to the initial starting time only. Its effect on unfinned tube is more obvious than that on the finned tube due to the increase of contact area, which speeds the cooling of the liquid region. It is observed that the mass of ice formed under the effect of natural convection is less than that formed for conduction controlled freezing by about 27%. 

Biography:

Wanchai Jiajan has completed his PhD from Nanyang Technological University, Singapore. He has published 3 papers in international journals during his PhD program. Now, he is working at Aerospace Engineering Division as an Instructor in Royal Thai Air Force Academy. 

Abstract:

This paper presents a numerical investigation and wind tunnel testing of the aerodynamic performance of two different low speed tailless mini-UAVs: The standard RTAFA-1 tailless mini-UAV and a new design tailless mini-UAV with stabilizer winglets. Reynolds averaged Navier-Stokes was applied to predict aerodynamic performance and longitudinal static stability of two different aircrafts. To confirm the numerical approach, the full-scale of two different tailless mini UAV were modelled to test in high quality flow Royal Thai Air Force Subsonic Research Wind Tunnel (SRWT). The experiments were performed over a wide range of Reynolds numbers (Re=100,000-500,000). The angle of attack was varied during the test over a range of pitch angles (-5° to +18°). In comparison of the experimental data with the simulation predictions, good agreement was observed for the lift and the pitching moment derivative; while the slightly over prediction of CFD drag results were obvious. The results show that the new design UAV provides significantly higher lift to drag ratio which is desirable to enhance overall aircraft performance, while remaining statically stable over the whole range of operating Reynolds numbers. 

Biography:

Leonardo P Chamorro is Assistant Professor in the Department of Mechanical Science and Engineering in the University of Illinois at Urbana-Champaign. He is affiliated in the departments of Aerospace Engineering, and Civil and Environmental Engineering. He has published over thirty peer-reviewed articles in leading journals and is serving as Associate Editor of the Journal of Energy Engineering, and as Academic Editor and member of the Editorial Board of the journal Energies. He leads the Renewable Energy and Turbulent Environment Group, and has developed a versatile experimental approach that combines state-of-the-art techniques, including 2D/3D PIV, computer vision, and 3D particle tracking velocimetry. 

Abstract:

Systematic experiments were carried out to uncover the physical processes modulating the onset of instability and development of turbulence over 2D and 3D sinusoidal roghness/walls. High-resolution particle image velocimetry in a refractive-index-matching flume was used to quantify high-order statistics. The 2D wall is described by a wave in the streamwise direction with amplitude to wavelength a/λx=0.05. The 3D wall is defined with a a/λy=0.1 spanwise wave superimposed on the 2D wall. The flow was characterized at roughness Reynolds numbers Rek=320-340 to capture the onset of transition; while the developing and developed flows were quantified at Re=4000 and 40000, based on the bulk velocity and the flume half height. Instantaneous velocity fields, turbulence quantities and POD reveal strong coupling between the topography and the turbulence dynamics. The spanwise superimposed mode on the 2D roughness topology is found to play a dominant role on the location of the flow instability and the dynamics leading to turbulence. In the developed flow, turbulence statistics show the presence of a well-structured shear layer that enhances the turbulence for the 2D wavy wall, whereas the 3D wall exhibits different flow dynamics and significantly lower turbulence levels, where turbulent shear stress shows 30% reduction. The likelihood of recirculation bubbles, levels and spatial organization of turbulence, and the rate of the turbulent kinetic energy production are shown to be severely affected in the 3D wall. 

Biography:

Yeng Yung Tsui has completed his PhD and Research Assistant work in 1987 from Imperial College. He joined the faculty of National Chiao Tung University, Taiwan ROC since then. He is currently a Full Professor in the Department of Mechanical Engineering. He was heavily involved in the development of CFD. His current interestes include modeling of two-phase flows and electrohydrodynamics.

Abstract:

Both theoretical and experimental procedures are employed to study the effect of corona discharge on heat transfer over a plate. The heated plate is grounded to form the collecting electrode. A thin copper plate is perpendicular to the collector and acts as the emitting electrode. A numerical procedure based on finite-volume methods is developed to analyze the electric and flow fields. Good agreements are obtained by comparing numerical predictions with analytical solutions for 1-D, 2-D and 3-D discharge problems. The experimentally determined current-voltage relations are used as boundary conditions in simulations. Heat transfer is enhanced by the ionic flow due to the corona discharging, which entrains more air to form a stagnation flow onto the heated collecting plate. Differences between predicted and measured temperatures are more significant when the applied voltage is low. This is mainly due to the heat loss from the heated plate which appears in the experiments but not accounted for in numerical simulations. The heat loss is relatively minor as the applied voltage increases, resulting in better agreements. It is found that the induced electric currents are high for smaller inter-electrode gap, leading to greater corona effect. However, the applied voltage allowed before breakdown of the corona discharge is higher for large gap, giving better heat transfer enhancement. This indicates that the inter-electrode distance and applied voltage need to be optimized to achieve the best performance

Biography:

Alex Neves Junior has completed his PhD from Federal University of Rio de Janeiro. At moment, he is Adjunct Professor at the Federal University of Mato Grosso and member of the Brazilian Association of Thermal Analysis. He was invited to participate in the book "Who is Who in Thermal Analysis and Calorimetry" by the Springer publishing company. He is reviewer of the Journal of Thermal Analysis and Calorimetry and Building Construction and Materials. He has requested for two patents on, “Non-Conventional Thermo gravimetry System in Controlled Chamber” and “New System of Non-Conventional Differential Thermal Analysis in Controlled Chamber”. 

Abstract:

In this work, the authors propose two methods to measure CO₂ capture in cementitious materials. One method is related to thermo gravimetry and the other is through mass gain on real time. Using a high initial strength sulphate resistant Portland cement pastes, the authors achieved the best conditions of CO₂ capture and measured an amount of 7% of CO₂ captured on the initial cement mass basis added through thermo gravimetric measurements and 15% of CO₂ captured in mass gain experiments on real time. 

Biography:

Przemyslaw Figura has graduated from University of Warsaw in Astronomy. He has worked as a Programmer and then started his PhD studies at the Space Research Centre, Warsaw. He is a researcher in this institute and currently he is finalizing his PhD.

Abstract:

We consider flows that preserve lines of a given external field. In particular, we focus on the magneto-fluids flowing in a magnetic field. Moreover, we treat the breakage of the line preservation regime as a process of the magnetic reconnection. To describe the magnetic field, we use the Euler potentials representation. Using this formalism, we formulate a line preserving flows equation that becomes the basis of our further studies. We obtain equations describing the time evolution of the Euler potentials for the considered regime. We provide two approaches to find the special case solutions of the obtained equations, because in general closed-form solutions of the equations do not exist. Also, we consider small perturbations and their implications of our obtained line preserving flows equation as well as perturbations of the Euler potentials time evolution equations. We illustrate them with some simple examples.

Biography:

Carlos Andres Candelo has just finished the degree in Industrial Technologies Engineering. His final degree's thesis was related to the fluidic actuators, and concretely the model that is going to be exposed. His professional experience was made during the years of the degree. He worked giving private lessons to people of high school. In summer time, he goes to different work camps as a volunteer.

Abstract:

Flow control actuators have long been in the focus of research in the fluid mechanics field since they are able to reduce drag on bluff bodies, increase lift on airfoils and enhance mixing. However, their performance in real applications must assure reliability and long lifetime. Among the different existing actuators, ZNMF (zero net mass flow), plasma actuators, MEMS (Micro-Electro-Mechanical Systems), fluidic oscillators and combustion driven jet actuators; only the plasma, fluidic and pulsed combustion actuators do not have moving parts, which is a priority and gives confidence regarding their reliability. Fluidic oscillators are able to produce a pulsating jet with the required momentum, although it appears their design needs to be adapted to each application. Original fluidic oscillator designs goes back to the 60s and 70s, left nearly unchanged for over 40 years. Among their applications in flow control, it is worthy to mention their use in combustion control, mixing enhancement and flow deflection, modifying flow separation in airfoils, boundary layer control on hump diffusers used in turbomachinery, flow separation control on stator vanes of compressors, drag reduction on road vehicles and cavity noise reduction. Following the present introduction it appears that fluidic actuators could be much widely used in the future, and it is according to the authors, worthy to better understand their behaviour in order to further improve their performance. In the present paper, a given type of fluidic oscillator is studied via 3D-CFD. Initially, the original oscillator dynamic performance was studied. In the second stage, internal dimensions were modified and for each case the dynamic behaviour was evaluated. Among the results, it is interesting to mention that a given fluidic oscillator working at a given Reynolds number is capable of producing different frequencies and amplitudes. The study was done considering the fluid as incompressible and turbulent. Several turbulent models were also evaluated.

Biography:

Bo AN has completed his Master’s degrees from Northwestern Polytechnical University School of Aeronautics in 2013 and Universidad Politécnica de Madrid School of Aeronautics in 2015. Now he is a PhD student of Universitat Politècnica de Catalunya, BarcelonaTech. His major is Computational Fluid Dynamics. He used to study ice accretion on airfoil, lattice Boltzmann method and traditional computational methods.

Abstract:

The numerical stability behavior of the original lattice Boltzmann method deteriorates as Reynolds number increases, so the application of lattice Boltzmann method is traditionaly limited to low Reynolds numbers. Although, to a certain extent, this dilemma could be released through the technology of grid refinement, it is not practical to merely refine the grid, especially, when dealing with problems with a complex geometry or relatively high Reynolds numbers. Two improved lattice Boltzmann methods are applied in this paper, known as multiple relaxation time lattice Boltzmann method and large eddy simulation lattice Boltzmann method, both of these methods have largely improved the stability behavior of LBM. Some numerical cases are studied including, lid-driven cavity, bottom surface mounted square and flow around blunt bodies. Some results of the simulations performed are presented.

Biography:

Hui Yang completed his Graduation from Zhejiang University, Master's degree in 2011 and joined Zhejiang Sci-Tech University to carry on research. As an Assistant Researcher, he mainly engages in the research of fluid machinery and engineering. He has a certain technical accumulation on the internal flow stability of fan and its optimum design. Now, he is in charge of 2 scientific research projects on fans and has published 5 papers and authorized 8 patents.

Abstract:

Study of flow around planar cascade of aerofoils is an important basis for the research of flow field in fans and compressors with aerofoil impeller. The energy gradient theory is used to analyze the flow stability of flow around planar cascade of aerofoils under low Reynolds number. The influence of attack angle and airfoil blade spacing on the flow stability was studied. The flow was governed by the unsteady incompressible Navier-Stokes equations coupled with the Spalart-Allmaras turbulent model. The finite volume method was used to discretize the governing equations and the Semi-Implicit method for pressure linked equation algorithm was employed to iterate the system of the equations. It was found that the distribution of the energy gradient function K was in agreement with the variation of the flow field and flow instability could be showed by the energy gradient function K. The position of flow separation at the trailing edge of airfoil was corresponding to the distribution of the energy gradient function K at high angle of attack. It was found that the development of the flow stability was much affected by the energy gradient function K from the comparison of the flow field for different cases. The research results can be used for further study of flow stability in the turbomachinery. 

Biography:

E Z Massoud is a PhD student at Department of Naval Architecture, Ocean and Marine Engineering, Strathclyde University, Glasgow, United Kingdom. She is, as well, working as Teaching Assistant in Mechanical Engineering Department, Arab Academy for Science, Technology & Maritime Transport, Alexandria, Egypt.

Abstract:

Biography:

E Z Massoud is a PhD student at Department of Naval Architecture, Ocean and Marine Engineering, Strathclyde University, Glasgow, United Kingdom. She is, as well, working as Teaching Assistant in Mechanical Engineering Department, Arab Academy for Science, Technology & Maritime Transport, Alexandria, Egypt.

Abstract:

In subsea oil and gas production system, the hydrocarbons from the reservoirs are transferred as multiphase mixture of oil, gas, water, sand, salt, H₂S, CO₂ and other unwanted products. Slug flow is one of the important and complex multiphase flow regime encountered in oil and gas production systems. The slugging problems may cause flooding of downstream processing facilities, severe pipe corrosion and structural instability of pipeline and further induce the reservoir flow oscillations and a poor reservoir management. In the present study, computational fluid dynamics simulation is used to investigate two phase slug flow in vertical subsea oil and gas production system pipelines using the volume of fluid (VOF) methodology implemented in the commercial code ANSYS Fluent. The viscous, inertial and interfacial forces have significant effect on the hydrodynamic characteristics of two-phase slug flow. These forces are investigated by introducing a wide range of inverse viscosity number, N_f; Eotvos number, Eo and the Froude number, Fr; in the present study. The simulation accounts for the hydrodynamic features of two phase slug flow including the shape of Taylor bubble, volume fraction distribution, slug frequency and velocity and thickness of the falling film. The increase in Taylor bubble rising velocity in inertia dominated flows causes an increase in the velocity of fully developed falling liquid film. The CFD simulation results are in good agreement with previous experimental data and models available in literature.