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.