Vienna
March 17-19, 2014
Accepted Sessions
  • jamesd's picture
    James Dorris
    CD-adapco

    Conjugate Heat Transfer analysis is performed on a split phase induction motor with internal fan-driven air-cooled topology by using the electromagnetic losses computed in SPEED and mapping them onto the real-world 3-D geometry in STAR-CCM+. Temperature dependent copper losses (I^2R) are modeled in both the stator winding and the aluminium rotor squirl cage. Simulation and measured temperatures are compared to show accuracy of this process. An improved, "vented" stator geometry is swapped into the STAR-CCM+ simulation to determine the potential impact of this design change upon the machine's thermal performance. 

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  • MEnde's picture
    Marcus Ende
    IAV

    The last decades of automotive development have become a race driven by emission regulations, fuel efficiency and customer requirements. To meet future rrequirments, more and more virtual development is required to further accelerate the proces. One of the most significant trends in engine development is downsizing, which leads to smaller engines with higher power output and therefore much higher thermal loading. To reach a high levels of reliability and engine life an optimized and very effective cooling system is needed.

    3D CFD has become a valuable and efficient tool to guide the IC engine design engineer to optimize the cooling system. Next to pure coolant flow field investigations, detailed studies of the engine-internal heat transfer have become possible, such that resulting structural temperatures can now be assessed with reasonable accuracy. However, in order to achieve reliable results every individual process along the heat transport path from gas side to coolant side needs to be analyzed in detail and the corresponding sub-models adjusted and verified.

    This paper describes the developed methodology together with individual sub-model verification steps. The whole process is performed entirely using CD-adpaco simulation software. Beginning at the gas-side the combustion process is modeled with es-ice and STAR-CD. The complete engine structure and coolant regions are meshed and solved as a CHT model in STAR-CCM+ with model-sizes up to 20 million cells.

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  • mcji8ar2's picture
    Alistair Revell
    The University of Manchester

    Hybrid RANS-LES methods can be very useful when high detailed insight into turbulent flow is required, in which instantaneous fluctuations play a critical role. For example when a high-accuracy prediction of complex flow separation is needed, or for insight into thermal fatigue due to fluctuating flows at different temperature, or for the approximation of acoustic noises levels via measurement of fluctuating pressure. Compared to the full deployment of Large Eddy Simulation (LES), the Hybrid methods are designed to retain an economical RANS turbulence model in regions where they are expected to perform well; limiting the use of Eddy Simulation approaches to specific areas where more detail/accuracy is needed.

    We report progress in an approach known as Embedded Simulation (ES), whereby we prescribe the limits of these regions in advance and use synthetic turbulence methods to pass from the time-averaged RANS fields into the fluctuating fields (where one can use either LES, or even the DDES schemes as necessary. We demonstrate how this can be achieved today using existing tools in STAR-CCM+, and also provide insight into the more advanced ES approaches currently under development that will provide a comprehensive and semi-automated usage of ES methods in the future.

  • angelo.flemings's picture
    Angelo Flemings
    Red Cedar Technology

    In this talk, we'll focus on how leading companies are streamlining the virtual product development process by implementing four enabling technologies, namely:

    • Process automation
    • Scalable Computation
    • Efficient Design Exploration, and
    • Sensitivity & Robustness Assessment

    We will highlight how the HEEDS technology from Red Cedar Technology is being used to accelerate design processes, improve workflow between CAD and CAE, discover better designs, and identify the most robust designs for manufacturing.

    Key case studies in automotive, aerospace, life sciences and energy will be used to illustrate return-on-investment and innovation.

    We will show how and why state-of-the-art practices in direct optimization are overtaking traditional surrogate modeling (RSM) and DOE techniques to yield dramatic performance enhancements.

  • Frederik P.'s picture
    Frederik Popig
    BTU Cottbus

    Radial inflow turbines are subjected to high engine order excitation that causes high cycle fatigue. In order to fulfill endurance and integrity requirements, it is necessary to determine the high engine order excitation that depends on structural as well as aerodynamic operating conditions. The lifetime limiting dynamic stresses induced by blade vibration due to high engine order excitation can be estimated by evaluating the forced response function of the tuned system. In order to calculate the forced response function, it is necessary to predict aerodynamic excitation forces and aerodynamic damping according to the considered vibration mode at specific operating conditions.

    Aiming at the numerical prediction of aerodynamic damping and forcing the unidirectional methods which are used to determine modal excitation forces, aerodynamic damping and vibration amplitudes are explained. Furthermore, the setup of a forced response simulation and an aerodynamic damping calculation are presented. For the evaluation of the modal excitation forces and aerodynamic damping, the unsteady time accurate solver has been used. Additionally, harmonic balance flutter simulations have been used for the prediction of aerodynamic damping which will be compared to the time accurate solutions in terms of quality and effectiveness.

     

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  • mcarriglio's picture
    Marco Carriglio
    ESTECO SpA

    This presentation deals with the multi-objective optimization of a mechanical filter for solid suspended substances used in extractor hoods of industrial kitchens, coupling STAR-CCM+ with modeFRONTIER. The filter performance has been analyzed by means of a STAR-CCM+ multiphase and unsteady model, that has been experimentally validated in Trieste University laboratory through a Laser Doppler velocimetry.

    Since the baseline performance is not satisfactory for particles of diameter less than 10 micron, the geometry has been optimized through the coupling of multi-objective optimization environment modeFRONTIER with STAR-CCM+, in order to maximize the separation efficiency minimizing at the same time the pressure losses. The coupling to STAR-CCM+ was accomplished via modeFRONTIER’s new direct interface with Optimate. This integration allows the geometry to be modified either in the STAR-CCM+ CAD Modeler, or, as in this case, in a separate CAD tool.

    Efficient optimization algorithms based on adaptive Response Surfaces have been applied, and the CFD simulations have been distributed automatically on the available computational resources through the Grid system. The separation efficiency of the optimized geometry has been improved significantly by the automatic execution of a small number of CFD simulations.

  • Vivek_Kumar's picture
    Vivek Kumar
    Endress+Hauser Flowtec AG

    Flow in and after the industrial bends are quite important from the flow metering point of view. There is a wide-range of studies focusing on simulations of turbulent flows through curved pipes. For flow metering it is important to know and understand that how the flow develops after a disturbance. There is little information in the literature how the flow develops after such a disturbance. In the present study, we focus on the scaled resolved by a Large Eddy Simulation (LES) of an in-plane and out-of-plane bend at a relatively low Reynolds number 20,000.

    LES results served as a benchmark for the RANS simulations using different turbulence models and wall treatments. For all simulations, the integration was performed up to wall that is y+ of 1. From computing effort point of view, it is quite impractical to employ LES approach in industrial environment. Therefore, our objective was to find the most suitable RANS-model of STAR-CCM+ for the above mentioned two situations. Furthermore, we have established and showed the best practiced guidelines for carrying out a Large Eddy Simulation.

    The turbulence models that are studied are 2 layer realizable k-epsilon (RKEPS-2L), two layer standard k-epsilon (SKEPS-2L), v2-f k-epsilon (V2F), k-omega Shear Stress Transport (SST), low Reynolds number k-epsilon (low-Re KEPS) and the two-layer Reynolds stress model (RSM-2L). The results reveal that the RKEPS-2L is the only model which can be adopted for both the simulations. Another interesting observation in this study is that k-omega SST model fails to predicts the flow development in both the cases. There is no other RANS model which serves our requirements for both the cases.

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  • didier.halbronn@cd-adapco.com's picture
    Didier Halbronn
    CD-adapco

    Didier Halbronn, CD-adapco's VP of European Sales, opens the STAR Global Conference with a discussion of "Multidisciplinary Design Exploration" in which he will identify some of the highlights of the conference program.

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  • David Breashears's picture
    David Breashears
    Arcturus Motion Pictures

    David Breashears is an American mountaineer and filmmaker. In 1985, he became the first American to reach the summit of Mount Everest twice. He is perhaps most famous for guiding Richard Bass to the summit of Everest, thus completing Bass's ascent of the seven highest summits on each continent.

    He has worked on feature films including "Seven Years in Tibet" and "Cliffhanger", as well as on the award-winning documentary "Red Flag over Tibet". In 1983 he transmitted the first live pictures from the summit of Mount Everest and in 1985 he became the first American to reach its summit more than once. He is the recipient of four Emmy awards for achievement in cinematography.

    Breashears has made eight expeditions to Everest, reaching the summit five times. He has climbed to the summit of 24,494 ft (7,466 m) Ama Dablam in theHimalayas, and is known in climbing circles for free climbing some of the most technically challenging rock walls in Colorado as a young man.

    In 1996 he co-directed, photographed and co-produced the acclaimed IMAX film "Everest" and contributed still photos to the best selling book "Everest: Mountain Without Mercy". In 1998 he was a director and producer for a Nova television program, "Everest: The Death Zone", in which he and fellow mountaineer Ed Viesturs climbed Everest while undergoing physical and mental tests to record the effects of altitude on humans.

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  • mstadler's picture
    Michael Stadler
    Ninsight

    The project aims to perform a multi-objective evolutionary optimization of an axial fan. The objective functions minimize noise generation and maximize the aerodynamic efficiency. The fan consists of seven individually shaped blades which are fitted with winglets and turbulators. This particular arrangement helps to reduce tonal noise.

    The geometry of the blades is parameterized using the circumferentially averaged swirl and a corresponding solution of the Euler equations in Mathematica. The geometry of the winglets, the hub and the shroud is parameterized in the 3D-CAD Modeler of STAR-CCM+. For the evaluation of the objective functions, Large Eddy Simulations (LES) are carried out. The optimization is performed using a meta-model assisted NSGA-II algorithm. The final design of the axial fan is chosen from the resulting Pareto front.

    Due to the large set of geometrical parameters, conventional aeroacoustic optimization strategies based purely on physical experiments may become tedious. However, the proposed algorithm helped to significantly accelerate the design process.

     

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  • Cesar Augusto's picture
    Cesar Augusto Cortes Quiroz
    University of Hertfordshire

    Micromixers are key components in several micro electro-mechanical and lab-on-a-chip systems, which are increasingly applied in fields such as chemistry, chemical synthesis, bio-technology and environment control.

    A CFD-based study is presented, which includes design modeling, flow and mass transfer simulation and geometric parametric analysis of a passive micromixer that presents curved shape obstacles and grooves in the mixing channel as main geometric features. The parametric study helps to identify the effect of some geometric dimensions on mixing quality, pressure loss and shear stress levels. The aim of the study is to reduce the pressure drop while keeping the mixing level in the channel with the inclusion of grooves which create additional secondary flows in a chaotic pattern and reduce the effect of the nozzle formed at the tip of the obstacles. 

    To our knowledge, this specific combination of obstacles and grooves in micromixer geometries has not been previously investigated.

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  • yml@ilight.com's picture
    Yves-Marie Lefebvre
    Intelligent Light

    STAR-CCM+ and FieldView have been used, through an extract based post-processing workflow, to analyze a very large transient simulation case. This method not only allowed to monitor simulation results over time, such as the maximum temperature of thousands of car parts and their comparison with the critical temperature of each material. But also to investigate transient phenomena interactively, in order to gain better understanding. To our knowledge, this work is unprecedented in the automotive industry.

  • Vijayk's picture
    Vijaykumar Kamalakannan
    CD-adapco

    Recent advances in automated mesh generation, availability of high-fidelity and fully-coupled physics, and increased computational power are necessary and enabling factors for CFD-based design of next generation rotor-craft systems. The incorporation of CFD estimates early in the design stage is beneficial for obtaining improved performance predictions as well as to reduce the number of design iterations required. It is with this aim that numerous physics capabilities and enhancements were added to STAR-CCM+ for complete rotorcraft simulations. Rotor performance prediction methods available in STAR-CCM+ range between virtual blade model utilizing blade element momentum theory to high-fidelity, transient overset mesh computations. This presentation highlights a number of technical validation studies namely – rotor/fuselage interaction using overset approach tested on ROBIN helicopter, high-fidelity modeling and prediction of rotor hub drag, and fast estimation of rotor trim and performance using virtual disk model.

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  • sebastian.bilz's picture
    Sebastian Bilz
    IAV GmbH

    A promising alternative to fossil fuels would be the utilization of a fuel cell as a powertrain for vehicles instead of a combustion engine. Inside the fuel cell, the reaction of hydrogen at a catalyst is used to convert chemical energy into electric energy and heat. This new technology offers a great potential for optimizing the components of this system. Reasonably, the on-going process can be realized with CFD-simulations.

    It is a matter of common knowledge that the water content of the membrane influences proton conductivity. An option to ensure the supply of water, and to protect the membrane from dehydration, is to install a humidifier into the cathode stream before it enters the cell.

    The humidifier itself contains a semipermeable membrane which separates liquid water (water-to-gas humidifier) or gas with a high relative humidity (gas-to-gas humidifier) from air for the supply of the cathode. Besides the exchange of heat, there is a transport of water against the gradient of activity. Consequently, this exchange results in a higher content of water in the cathode inlet stream.

    STAR-CCM+ cannot handle the diffusion through a semipermeable membrane. Hence, it is necessary to develop a modelling approach to calculate the mass transfer through it. The amount of water which will permeate through the membrane is calculated with “user field functions”. These functions read the necessary properties and, concurrently, simulate the transport of water for each iteration. The mass transfer will produce a fluid film on the dry side of the membrane. This liquid evaporates into the cathode stream from there. Furthermore, the model will consider the condensation of vapor on the damp side of the gas-to-gas humidifier. The results of this methodology agree with validation data.

    The developed simulation approach of a membrane humidifier in STAR-CCM+ with the help of the above mentioned “field functions” will be described in this presentation.

  • faissal.fdil's picture
    Faissal Fdil
    Lotus Cars Limited

    ART Grand Prix, a motorsport company based near Paris in France, is committed to the highest level of motorsport. Competing actively in GP2, GP3 and GT championships, this team has built a strong palmares over the last decade. Some of their former drivers, like Sebastian Vettel and Lewis Hamilton, subsequently became world champions in Formula 1.

    Without denying the talent of the drivers, their success is not only due to them. Behind these victories and these titles, there is a team of mechanics and engineers dedicated to extracting the best from the cars while respecting the technical, safety and sporting regulations. ART competes in monotype championships where vehicles are provided by the organizer. The flexibility of engineers, although greatly reduced, can help to provide a critical edge, which is often the difference between victory and being a "runner up".

    In our case, we are in the off-season. The staff in charge of the GP3 program prepare what looks to be a promising season. The cars were renewed, and are now more powerful. As a consequence, they require new settings, especially for the aerodynamic setup. My job here as a trainee was to calculate the rear wing polar curve for given angles of attack by performing steady-state 2D CFD calculations on STAR-CCM+. The objective of this study is to define the values ​​of CD and Cl for the rear wing, with and without gurney. Therefore, we will be able to analyze the impact of a gurney in our configuration and subsequently update the aerodynamic setup for the new car.

  • leibbrandt@fh-nordhausen.de's picture
    Pascal Leibbrandt
    Fachhochschule Nordhausen - University of Applied Sciences

    For a new solar flat-plate collector, which is composed of plane glass plates, two aspects of the development are illustrated.

    Firstly, the fluid distribution is examined for the occurrence of the heat-carrier fluid in the space between the plates. Starting from a circular port a volumetric flow should be generated through the interspace between the panes. For this, different geometries are analyzed. The distribution is optimized with regard to the full-volumetric flow and the pressure loss.

    Secondly, the natural convection is examined between the panes of the insulating layers by using different gas models and network studies. The CFD solutions are compared to analytical values. The problem of convective flows will be discussed as a function of the inclination angle and the pane spacing.

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  • Bianca Cefalo's picture
    Bianca Cefalo
    Active Space Technologies

    'The hardware for a Mars exploration mission shall be designed to operate during exposure to the Martian dust devil winds.

    The current numerical investigation aims to predict the aerodynamic loads and the convective heat transfer coefficient on the surface of the geophysical instruments deployed on Mars. An additional issue is the stability analysis of the payload, according to the maximum ground slope detected. A detailed 3D model of the instruments has been realized, discretizing the fluid domain with a high-resolution volume grid of more than 3 million tetrahedral cells. The Martian flow field is properly simulated considering Mars atmospheric composition. Aero-thermal loads due to dust devil boundary-layer have been estimated according to a 4-region logarithmic law for the velocity profile and a day time thermal profile in survival mode. The analysis is performed by STAR-CCM+ 8.04.007, solving the set of steady RANS equations with the segregated flow approach and the realizable k-ε turbulence model.'

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  • tuaskan's picture
    Tunc Askan
    Technische Universität Berlin

    According to the Institute for Energy of the European Commission Joint Research Centre, HVAC (Heating, Ventilation and Air Conditioning) accounted for 11% of the EU electricity consumption in 2007. Annual energy simulations of buildings are increasingly being used for optimization of energy consumption.

    These simulations primarily rely on one-dimensional methods. Computational Fluid Dynamics on the other hand are generally utilized in building applications among others for predicting thermal comfort and developing HVAC components. Currently annual CFD simulation of one room or even an entire building is practically impossible due to limited computational power.

    At the Hermann Rietschel Institute, department of Building Energy Systems at the Technische Universität Berlin, a new method for annual energy simulation is being developed, which makes it possible to run 3D annual energy simulations using existing CFD models within acceptable calculation times. With this method, it is also possible to run flow simulations for the critical zones within a building, where the annual energy simulation delivers realistic boundary conditions.

    A case study for an office building using this 3D method is carried out and the results are compared with a 1D simulation. During this study, the parallel performance of the 3D simulation is also tested. This case study showed that, it is possible to run 3D annual building energy simulations with this method in practice.

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  • gjudex's picture
    Gregor Judex
    Dassault Systèmes Austria

    Solenoid valves are electromechanical valves that are used to control the flow of liquids and gasses. These valves are controlled by an electric current which runs through a solenoid. The electric current, when activated, provides an electromagnetic (EM) force which enables the motion of a plunger that shuts off or opens fluid flow. From a computational fluid dynamics perspective, modeling the valve closing poses severe numerical challenges due to fluid mesh pinching. Apart from this, accurate evaluation of electromagnetic and fluid dynamic forces and an understanding of their interaction with the valve’s structural components are essential to accurately simulating the valve dynamics. 

    In this paper, we describe a methodology for modeling the coupled electromagnetic and Fluid Structure Interaction (FSI) analysis of a solenoid valve. A seamless integration between various analyses techniques have been used to simulate the complex multiphysics interactions that are seen in the valve operation. Abaqus electromagnetic analysis capability is used to accurately measure the forces imparted on the plunger due to electric currents. This force is subsequently used in a fluid-structure interaction analysis to model the opening behavior of the valve.  A co-simulation approach is undertaken utilizing Abaqus and STAR-CCM+. The methodology utilizes over-set mesh technology in STAR-CCM+ to account for fluid mesh pinching.  

  • FabioKasper's picture
    Fabio Kasper
    CD-adapco

    Gas-solid flows are present in many industries such as Oil & Gas and Chemical Processes, and can be measured experimentally or by numerical simulations. This work presents the results of both.

    The experiments were conducted in a test facility where vertical and horizontal sections of a pipe were selected as probing stations with radial profiles for axial solid velocities, obtained using Particle Image Velocimetry (PIV) technique. The test operating conditions behaved as a dilute flow and the solid particles had similar diameter compared to those applied in FCC units. The numerical simulations were run in STAR-CCM+ and a Grid Convergence Index (GCI) study was performed using Roache's approach. The refinement factor between the consecutive hexahedral meshes given by the directed mesher was accomplished with the help of HEEDS MDO. Turbulence in the gas phase was modeled with the standard k-epsilon and Reynolds Stress models whereas on the solid phase, a few different approaches were made for the model closure, such as the inviscid model and the Kinetic Theory of Granular Flows (KTGF).

    Results showed that both inviscid and KTGF models produced good agreement with the experiments among the stations, particularly in regions of developed flow.

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