• TRANSPORT TECHNICS. INVESTIGATION OF ELEMENTS. RELIABILITY

    Design of a sailplane based on modern computational methods

    Trans Motauto World, Vol. 6 (2021), Issue 2, pg(s) 47-50

    The purpose of the current study is to evaluate and apply a new approach to the design process of an aircraft with a high aspect ratio wing, based on modern understandings and development in the fields of aerodynamics and computational fluid dynamics. Conventional methods rely on semi-analytical models for describing different flow characteristics and interactions with bodies. The classical approach requires numerous coefficients to account for unknown effects, what is more, such workarounds are derived for well-defined cases and are not easily applicable for complex problems which could be dangerously misleading. CFD analysis, based on new developments in computational machines, give the possibility of analyzing complex aerodynamic interactions such as shading, downwash, ground effect and vortex shedding. Such use of innovative technology has already proven itself to have beneficial effect on reduction of cost a nd human error by being able to simplify and speedup many of the calculations without the need of coefficient adjustments.

  • TRANSPORT. SAFETY AND ECOLOGY. LOGISTICS AND MANAGEMENT

    The wind gusts effects on human body based on cfd simulations

    Trans Motauto World, Vol. 5 (2020), Issue 4, pg(s) 138-142

    In this paper, the impact of wind forces on human bodies is shown. Like many meteorological phenomena, the influence of wind energy applied to human bodies is inevitable which comes into the spotlight of the scientist only when the wind becomes violent and extremely disturbing. Based on weather and observations in February 2019, abnormal wind characteristics in Albania are evidenced. On February 23, 2019, a very special situation in the Northern part of Albania, the region of Puka, with extreme values of wind parameters causing the phenomenon of “wind gust”, leading to a series of material damage and loss of human life, is evidenced. Researchers and predictors need scientific information on the impact of strong winds applied on the human body for specific conditions. Wind speed values in this region of the northern part of our country set records reaching extremely values (30 ÷ 35) ms-1 on the ground level. Taking a cue from this unprecedented situation, the effect of strong winds on the determination of aerodynamic forces acting on the human body using numerical simulations has been studied and so far, well investigated. For this study, we considered a human body with a height of 172cm. The investigation takes into account two different positions against the wind, frontal and lateral position traversed by wind speeds levels of 20m/s, 30m/s, and 40 m/s. The study concluded that strong winds can exhibit unimaginable and unaffordable forces, leading to fatal consequences for human life.

  • DOMINANT TECHNOLOGIES IN “INDUSTRY 4.0”

    DESIGN CENTRIFUGAL FAN VOLUTE WITH CFD NUMERICAL SIMULATION USING OPENFOAM-MATLAB COUPLING

    Industry 4.0, Vol. 4 (2019), Issue 6, pg(s) 297-301

    The main scope of this paper is to fully integrate simulation from open source CFD software with the Matlab App Designer program. The OpenFOAM-Matlab CFD interface allows one to conveniently setup fully turbulent incompressible Reynolds Averaged Navier-Stokes (RANS) CFD case all within an easy to use graphical user interface (GUI). Highlighting built-in CAD tools to create geometry (STL) for automatic mesh generation to OpenFOAM case file as well as a solution with post-processing and visualization with ParaView. Also, the cross-platform OpenFOAM CFD interface for MATLAB should allow the user to rapidly design the spiral casing in an engineering manner as an illustrative platform and coordinator between the inputs chosen by the user and the results which are displayed after calculations. Furthermore, the GUI should be a very flexible and user-friendly platform for spiral casing design according to the efficiency and static pressure recovery coefficient as well.

  • THEORETICAL FOUNDATIONS AND SPECIFICITY OF MATHEMATICAL MODELLING

    ENHANCED ASYNCHRONY IN THE VECTORIZED CONEFOLD ALGORITHM FOR FLUID DYNAMICS MODELLING

    Mathematical Modeling, Vol. 3 (2019), Issue 2, pg(s) 52-54

    The application of a rigorous CFD method and an all-encompassing algorithmic performance optimization method can make possible the CFD simulation of the extremely large-scale problems, which allows simulation of either larger systems, or more detailed simulation of systems that are already simulated. The CFD code has to show both efficient one-node performance and excellent parallel scaling. The record breaking performance on one node has been achieved before with application of the LRnLA algorithm and making use of many core parallelism as well as the vectorization. In the current work, the algorithm is extended for many-node parallelism. The algorithms is characterized by high parallelization degree, small number of node communication events, and may be concisely described and programmed on the base of the previously implemented one-node solution, which is a rare feature among the algorithms with temporal blocking in all four of the spatial and time dimensions.

  • Experimental and numerical analysis of wind turbine model

    Machines. Technologies. Materials., Vol. 13 (2019), Issue 5, pg(s) 206-209

    Global demand for electric energy is predicted to increase in the coming decades. Following this, different approaches for additional electricity production are analysed and tested worldwide. The EU supports the production and usage of electricity from renewable energy sources, particularly wind energy, because it provides electricity without giving rise to any carbon dioxide emissions. The presented work analysis the possibility for utilising of wind-generated electricity as a stand-alone system for small off grid cabin supply. The very basic turbine geometry was designed and numerically simulated with commercial CFD software. After that, the turbine model was printed using 3D printer and tested in laboratory environment. The comparison of numerically and experimentally obtained operating characteristics show reasonable agreement and strong potential for system optimisation and improvements.

  • VISUALIZATION FLOW ON THEPELTON TURBINE BUCKET BY CFD

    Machines. Technologies. Materials., Vol. 12 (2018), Issue 6, pg(s) 244-247

    In this study, series of CFD simulation were carried out for two phase flow (free surface), three dimensional geometry and turbulent flow through the pelton turbine. The present investigation employed on the pelton turbine bucket models various splitter angle and inlet velocity values for visualizing the flow pattern and identifying the force on the bucket. In this study, Two different bucket models were applied at different inlet velocity (20, 25, 30,35and 40m/s) and four different splitter angle (55, 75,90and 115) for finding the effect of every single parameter on the effective force on the bucket. The obtained results discovered that there is a linear relationship between force and inlet velocity on the bucket. It uncovered that relationship between splitter angle and force on the bucket is linear until 90 degree after that this relationship is a non-linear.

  • NUMERICAL MODELING OF A SHELL-AND-TUBE HEAT EXCHANGER

    Machines. Technologies. Materials., Vol. 10 (2016), Issue 3, pg(s) 44-47

    The aim of this work is numerical modeling of the hydrodynamics and heat transfer of a shell-and-tube heat exchanger. For the purpose of the study a 3D model with geometric dimensions corresponding to real was created. The simulations under the same boundary conditions as experiment were carried out. The independence of solution by the density and the shape of the mesh were investigated. For verification the experimental values for fluid temperatures at the outlets from the apparatus were used. The simulations of different operation modes in the apparatus were carried out. A modification in the geometry with the aim of raising the temperature on the cold fluid at the outlet was made. Results on vectors, velocity and temperature distribution in the apparatus were obtained. On the basis of the obtained results some design changes of the apparatus in order to improve the hydrodynamics have been proposed. The obtained results can be successfully used in the design, optimization and constructing of this type apparatus, as well as in the educational process.

  • CFD MODELLING OF A COMPLETE ELECTRIC ARC FURNACE ENERGY SOURCES

    Innovations, Vol. 4 (2016), Issue 1, pg(s) 22-24

    This paper, concentrates on a three-dimensional (3D) computational fluid-dynamics (CFD) model for coal combustion and electrode radiation inside an electric-arc furnace (EAF). Simulation of the complete EAF model includes combustion reactions of coal particles and radiation from electrodes. Particle surface and gas phase reactions were used to predict injected coal particle combustion. The CFD model provided detail information for the coal particles combustion and radiation interactions phoneme inside the electric-arc furnace.

    Results showed that CFD simulation could efficiently be used to develop and investigate EAF in design phase.

  • CFD MODELING OF TURBINE FLOW METERS

    Innovations, Vol. 2 (2014), Issue 1, pg(s) 6-8

    Computational fluid dynamics (cfd) techniques provide investigations in conditions where the real experiment can’t be fulfilled for some reason, so these tools have found their applications in many spheres of science and technology; in particular they are widely used in flow metering.

    Some of CFD applications we would like to propose and discuss in this work in the context of turbine flow meters. We discover non-drag type of turbine flow meters to check if created design with hydro-dynamic bearings should provide really floating rotor. For this purpose only numerical research can solve verification problem with minimal costs and simple realisation.

    CFD models are used to examine pressure contours and velocity profiles near floating rotor in turbine flow meters. A full three-dimensional flow simulation of realistic meter configurations has been carried out. Close attention was paid to simulation of the complete geometry of turbine meters including front-end and tail-end shapes of flow conditioner hub, metering cells, etc. Some advices to meters’ designing were given.