Papers by Keyword: Flow Simulation

Abstract: Carbon Fiber Reinforced Polymers (CFRPs) are essential to the aerospace industry, offering superior strength-to-weight ratios. Currently, the manufacturing of primary structures via standard autoclave curing is a robust, mastered process that successfully minimizes defects, keeping porosity levels below critical thresholds (typically < 1 %). Consequently, porosity is generally not considered as an issue in standard, optimized production lines.However, this stability may be affected by emerging industrial paradigms aimed at increasing production rates and reducing costs. The shift toward accelerated manufacturing – characterized by rapid heating rates, shortened cure cycles and by new manufacturing processes – and the introduction of complex material architectures risk re-introducing significant porosity. In parallel, there is currently no numerical model capable of accurately predicting porosity formation and evolution under these complex conditions. Existing simulation approaches are typically macroscopic and rely on homogenized porous media assumptions, failing to capture the essential micro-scale interactions between bubbles and fibres.To address this gap, this study presents an extended, custom multi-physics Computational Fluid Dynamics (CFD) solver built upon an existing OpenFOAM framework. The goal is to provide the first predictive tool for void evolution within realistic microstructures. The numerical framework couples a two-phase compressible flow model with the complete thermo-chemo-rheological physics of thermoset curing.The solver is applied to 2D Representative Volume Elements (RVEs) of a prepreg ply. Simulations of a standard autoclave cycle demonstrated the solver's ability to capture micro-scale dynamics, showing how voids are compressed and transported during the resin viscosity drop before being frozen at gelation. A parametric study comparing 3-bars and 7-bars pressures confirmed the model's physical ability in predicting void volume reduction.While currently focused on mechanical compression, the tool is designed to support the development of future manufacturing cycles. Future work will incorporate moisture diffusion physics and includes experimental validation via X-ray micro-tomography and in-situ synchrotron monitoring.

Abstract: Within the European research project ECOMISE advanced process simulation methods have been developed. Existing Software tools like RTMWorx and NX CAE have been extended in their capabilities and interface have been developed between them to have a direct data communication. In the present case a manufacturing process of a tidal blade was used to test and validate the development. In RTMWorx a new 3D solution was developed and an a import interface to read direct a structural model from NX with all related information’s like geometry, mesh and layup. The interface reads the ply information’s and calculates resulting permabilities for the layup. In NX CAE also interfaces and mapping algorithm have been developed to read information’s like filling factors from RTMWorx. In combination with the new functionalities to simulate curing, process induced deformation and residual stresses the virtual process chain enabling a complete analysis of the whole manufacturing process starting from a initial design with capabilities on draping including direct ply contour creation, infusion, curing and analysis of process induced deformation.

Abstract: Rotor blade design relies heavily on the aerodynamic theory. Extensive calculations are necessary in order to determine the blade parameters such as chord and thickness distributions, twist angle distribution and taper that is matched with the selected airfoil sections. For practical purposes, the engineers need a convenient means to verify their design. Wind turbine blades must be designed to operate in desirable performance. This research proposes a computer aided method that helps the engineers to examine the design and amend it in time. The numerical example shows good applicability of the methodology proposed. The proposed methodology not only lets us verify our design scientifically but also makes us understand the associated physical insight. The numerical example demonstrated here showed the converted power by the rotor can be evaluated easily by Flow Simulation according to the aerodynamics theory.

Abstract: In the case of electric railway vehicles of surface, the equipments which allow power supply are placed on their bodywork. The mode to dispose these equipments contributes to increase the resistance to motion of the vehicle due to the variation cross-section area. Gusts of wind that occurs during the movement of vehicles lead to increased aerodynamic forces. As a model analyzed, we considered the situation determined by the dispose of the equipments supply on the body of electric locomotive type LE 060 EA of 5100 kW, when such a vehicle is travelling with the first post station in the driving direction. The equipment’s components of supply were modeled geometric at scale 1: 1 in 3D. The obtained assembly was imported in an air flow simulation program to determine the aerodynamic resistances. To observe which is the influence of the gusts wind regarding the resistance to moving we considered five point values for wind speed: 5m / s, 10m / s, 15m / s, 20m / s and 25m / s. With results of the simulations we performed a comparative analysis.

Abstract: Gusts of wind with high speed can adversely affect the operation of the electric railway vehicles. These vehicles are able to move and to obtain a high performance, as long as the power supply is ensured. The variation of the vertical forces for maintaining contact between pantograph and catenary may cause interruption of the power supply of the electric railway traction vehicles. The placement of the capture equipment on the vehicle body determines appearance of aerodynamic forces acting on it. To see which are the vertical forces introduced by wind on active capture equipment, used at locomotives LE 060 EA of 5100 kW, we considered the EP3 type of pantograph as model. This was modelled at scale 1:1 taking into account the placement on the body of the locomotive. For the simulation of wind we considered three point values of its speed (10 m/s, 20 m/s, 30 m/s) and angle of eight values that are within the range of 0 deg – 180 deg. With the results of the simulation we have done a comparative analysis on the additional vertical forces introduced by wind for the cases analyzed.

Abstract: Because of growing global concern for the increasing energy demand and the resulting environmental impact of fossil fuel based energy sources, renewable and environmental friendly energy sources are critically sought. Wind turbines are generally conceived as the key renewable energy sources, but more innovative solutions should augment the classical design and control of wind turbines in order to improve the energy conversion efficiency. For areas outside the integrated grid system and harsh operation conditions in particular vertical axis wind turbines show promising results. This turbine design is previously considered less efficient, and thus the performance has not been sufficiently documented. This paper attempts to contribute in better understanding of the wind flow around the rotor, and the way the rotor components react to the resulting pressure. The turbine is first modeled in 3D CAD system and simulated in a flow simulator in a virtual wind tunnel. Then the iso-lines of velocity and pressure distribution are plotted at selected sections of the turbine plane and the profiles are studied to characterize the fluctuations of the dynamic pressure and identify the vulnerable zone of the turbine blades and the structure.

Abstract: This work aims to investigate the infiltration of a CaCO₃ filled resin in fibrous porous media (resin transfer molding process) using the PAM-RTM software. A preform of glass fiber mat (fraction 30%), with dimensions 320 x 150 x 3.6 mm, has been used in rectilinear injection experiments conducted at room temperature and injection pressure 0.25, 0.50 and 0.75 bar. The polyester resin contain 0% and 40% CaCO₃. The numerical results were evaluated by direct comparison with experimental data. The flat flow-front profile of the rectilinear flow was reached approximately half length of the mold. It was observed, that the both velocity infiltration and permeability have decreased with increasing the CaCO₃ content, thus, increasing the time to processing of the composite material.

Abstract: . Research on sea current energy uses as a sea current electrical power plant (PLTAL) in the region of Lembongan-Nusa Penida-Ceningan carried out since 2013, aiming to meet the demand for electricity in the coastal areas and remote islands. This study aims to design a marine current turbine which is planned to generate electricity of about 50 kW, with a construction system made ​​fixed and the turbine set inside that can spin revolving without interruption. Simulation model of the flow is done by using Computational Fluid Dynamics analysis, CFD. Simulations conducted in private with a variety of flow velocity and pressure of the sea water and various forms of channels. Based on the results obtained by simulation, the best flow of sea currents is with a slope angle of 30⁰ with a channel length of 15 m where the flow speed of the turbine of about 39 m/s with a flow pressure of 201,426 Pa, which predicted to be capable of producing 1,500 kW turbine power.

Abstract: 800x600 Like all industrial processes, injection molding can produce flawed parts. In the field of injection molding, troubleshooting is often performed by examining defective parts for specific defects and addressing these defects with the design of the mold or the characteristics of the process itself. Trials are often performed before full production runs in an effort to predict defects and determine the appropriate specifications to use in the injection process [1]. Gate solidification time is important, as it determines cycle time and the quality and consistency of the product, which itself is an important issue in the economics of the production process. Holding pressure is increased until the parts are free of sinks and part weight has been achieved. [2] The number of triangle in the mesh has an impact on calculation times. Each triangle has three nodes and the calculations done by the SolidWorks Plastics solvers are performed at each of those nodes. So, a higher number of elements mean a higher number of nodes and as the number of nodes increases, compute time increases. That said, element counts up to 100,000 should solve in a reasonable time, while element counts over 100,000 may take longer to solve. Gates vary in size and shape depending upon the type of plastic being molded and the size of the part. Small gates have a better appearance but take longer time to mold or may need to have higher pressure to fill correctly. Large parts will require larger gates to provide a bigger flow of resin to shorten the mold time. In this paper we will study the influence of the gate shape and location over the specimen. We will study in particular the fiber orientation for a material reinforced with fiberglass.

Abstract: Traffic simulation, a powerful scientific tool, can be applied to both transportation planning and to transportation design and operations. In this paper, a micro-simulation model is developed to simulate the behavior of individual vehicles on the freeway and is used to evaluate the impact of changes in efficiency and safety resulting from changes to traffic flow and speed limits. All aforementioned influences are expressed at a quantitive level.