B5
System Level Simulation 1

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08:35
conference time (CEST, Berlin)
Thermofluiddynamic Pre-design of a Primary Surface Heat Exchanger Under the Influence of Heat Radiation Using 1D/3D Coupled Simulation Method
26/10/2021 08:35 conference time (CEST, Berlin)
Room: B
T. Xie, T. Starick (BTU Cottbus-Senftenberg, DEU)
T. Xie, T. Starick (BTU Cottbus-Senftenberg, DEU)
Within the Framework of the "TurboFuelCell (TFC)" a highly integrated and compact energy conversion system based on Micro Gas Turbine Solid Oxide Fuel Cell (MGT-SOFC) hybrid process is being developed by the team at BTU-Cottbus Senftenberg. This work focuses on the extension of the pre-design process of a primary surface heat exchanger (PSHX), which is a key component for the coupling between MGT and SOFC, using an 1D/3D hybrid simulation method for the understanding of its behaviour under the influence of heat radiation. In a MGT-SOFC hybrid process the high temperature heat exchanger plays an important role in preheating the fresh air to a minimum operation temperature necessary for SOFC. Due to the special location of this PSHX in the TFC, it is constantly exposed to heat radiation from the SOFC module, which requires additional consideration of its influence for better model accuracy. A first design, which is later extended through an 1D Flow network model, based on ϵ-NTU method is presented. A complete 3D-CFD simulation with consideration of heat radiation is initially employed for the whole flow process to examine the first design. However, this approach proves to be highly computationally expensive due to the large dimensional difference between the plenum for cathode exhaust air and the fine channels in the PSHX. To reduce the computational effort, the flow and heat transfer in the PSHX is modelled by 1D elements. The flow in the plenum is simulated by 3D-CFD, which better accounts for convection and thermal radiation. A comparison between 3D-CFD and 1D/3D hybrid model is performed. A significant reduction of simulation time and computing resources can be achieved for well calibrated hybrid model without compromising on accuracy. In the talk, the effect of insulation layer thickness variations on the heat transfer on the plenum side due to heat radiation and their influence on the heat exchanger efficiency are discussed. Consequently, design improvements are realized based on the previous findings. Finally, the 1D/3D hybrid simulation method is evaluated and prepared for the general applications in thermal management of machines based on coupled MGT-SOFC process.
primary surface heat exchanger, heat radiation, 1D/3D hybrid simulation, MGT-SOFC
08:55
conference time (CEST, Berlin)
Web-based Team-oriented Modelling, Simulation, Optimization and Evaluation of Modular Mechanical Systems
26/10/2021 08:55 conference time (CEST, Berlin)
Room: B
W. Witteveen (FH OÖ Forschungs- und Entwicklungs GmbH, AUT); J. Schönböck (University of Applied Sciences Upper Austria, AUT)
W. Witteveen (FH OÖ Forschungs- und Entwicklungs GmbH, AUT); J. Schönböck (University of Applied Sciences Upper Austria, AUT)
To handle the ever-growing complexity of modern products in vehicle, machine or plant design, these products are increasingly divided into subsystems or modules. Specialized teams of experts develop these more or less complex modules at one or more locations. If all subsystems meet certain criteria, they are assembled to a complex total system. The total system is then also tested with regard to certain criteria and released if possible. In case of problems, the teams of experts work together on the total system to find a solution. In present-day virtual development of modular systems, these realities are only insufficiently represented. Common software products do not allow for intuitive synchronous collaboration, neither in modelling, in simulation, nor in discussing results. DisMoSim (Distributed modeling and simulation of cyber-physical systems) is a project of the University of Applied Sciences Upper Austria, in which the vision of a seamless and team-oriented virtual product development of modular systems is implemented using multi-body simulation as an example. The goal is the design, prototypical implementation and evaluation of new digital tools and algorithms to support collaborative development at the same ("co-located") and different locations ("remote") by adopting standardized web technologies to guarantee a uniform and efficient data transfer. In the field of 3D modeling, new interaction and visualization techniques will support more effective and efficient teamwork within and between companies. Multitouch and pen-based inputs on large displays as well as the integration of mobile devices allow seamless group work at the same location or in distributed teams. By embedding an intuitive kinematics solver a virtual workshop is realized, in which several teams can build and join models, virtually test them and discuss results simultaneously. DisMoSim is an academic project without an industry partner. However, the project team is strongly interested in collaborations with companies so that the gained knowledge can be transferred into software suitable for industrial use.
Multibody systems, Modelling, Simulation, CAE
09:15
conference time (CEST, Berlin)
Approach to Support Frontloading in Product Development by Cross-Domain Simulation Models for the Prediction of System Performance Under Consideration of Relevant Thermal Effects
26/10/2021 09:15 conference time (CEST, Berlin)
Room: B
F. Leitenberger (Karlsruher Institut für Technologie (IPEK), DEU); S. Knecht, S. Matthiesen, A. Albers, T. Gwosch (Karlsruhe Institute of Technology - Institute of Product Engineering, DEU)
F. Leitenberger (Karlsruher Institut für Technologie (IPEK), DEU); S. Knecht, S. Matthiesen, A. Albers, T. Gwosch (Karlsruhe Institute of Technology - Institute of Product Engineering, DEU)
Early phases of product development processes have the inherent problem that they require engineers to make decisions for future development without having specific data or physical prototypes yet. One possibility to overcome this challenge is to use simulation models. To predict the system performance, cross-domain simulation models with lumped parameters are often used. In most mechatronic system models, the main focus is on the mechanical, electrical and hydraulic power flow. Very often temperature dependencies of parameters are neglected due to a lack of system knowledge and complicated interactions. The influence of the thermal domain on the mechanical and electrical parameters is getting more relevant due to increasing power densities in mechatronic systems. A prediction of the dynamic behavior of systems under strong thermal effects might not be reliable enough if temperature dependencies and their effects are not considered. A typical approach to incorporate thermal dependencies into a cross-domain simulation model is to create a co-simulation between the lumped parameter simulation model and a detailed heat-transfer simulation. This approach however comes with a high cost of resources like money and time which cannot be justified by model quality necessary in early product development stages. Another typical approach is a guess for the thermal influences on model parameters based on the experiences of previous product generations. These experiences might not be transferable when significant changes in those systems are made. Therefore, there is a lack of suitable support for the parameterization of thermal dependent parameters of cross-domain simulation models. This frontloading approach enhances decision making in the early phases of product development processes. The aim of this contribution is to describe an approach that supports the parameterization of cross-domain simulation for the prediction of system performance under consideration of relevant thermal effects. To achieve this, a lumped parameter simulation is supported by a conjugate heat transfer (CHT) simulation. The approach describes how the resulting power losses for a given load case are estimated using cross-domain simulation and how the resulting relevant heat sources are determined. These resulting heat sources are used as boundary conditions in the CHT simulation. The CHT simulation simulates the involved thermal phenomena and the resulting temperature distribution throughout the system. The resulting temperature distribution can be used to parameterize the values of the lumped parameters in the cross-domain simulation. The cross-domain simulation is tested again with the adjusted parameters. In this work, an electro-hydrostatic actuator (EHA) for the application in aerospace is used as an example of a mechatronic system under relevant thermal effects. To evaluate this approach, the predicted dynamic behavior of the EHA of the cross-domain simulation is compared to the measured behavior in test rig investigations. This comparison is done with and without the described approach. The load case is a periodic back and forth movement of the EHA. The evaluation variables are the deadband and settling time of the individual jumps of the movement. The result is that the deviations of the evaluation variables between the predicted and the measured dynamic behaviour is reduced by using the described approach. The cross-domain simulation model has an improved model quality due to a parametrization that considers the temperature dependencies. Therefore, this approach can be used to support the parameterization of simulation models for systems under relevant thermal effects. This approach has the potential to be applied to more systems and provide better prediction of system performance. This can reduce uncertainty in the early stages of product development and support the frontloading in product development.
Cross-domain Simulation, Conjugate Heat Transfer, Parameterization, Frontloading
09:35
conference time (CEST, Berlin)
Balancing Interior Environmental Quality and HVAC Energy Efficiency using 1D and 3D Simulation
26/10/2021 09:35 conference time (CEST, Berlin)
Room: B
T. Tumforde, S. Wischhusen (XRG Simulation GmbH, DEU); C. Luzzato, V.Nagarajan, V-M. Lebrun, A. Colleoni, A. Mann (Dassault Systemes, DEU)
T. Tumforde, S. Wischhusen (XRG Simulation GmbH, DEU); C. Luzzato, V.Nagarajan, V-M. Lebrun, A. Colleoni, A. Mann (Dassault Systemes, DEU)
Heating Ventilation and Air Condition (HVAC) systems have become an essential part of building equipment, ensuring superior Indoor Environmental Quality (IEQ), especially around Thermal Comfort and Interior Air Quality (IAQ). Conversely, energy efficiency is also becoming a growing topic of interest worldwide, as excessive power consumption and global warming are changing the way in which we engineer and integrate products. In countries subject to extreme weather conditions for example, such as Australia, HVAC energy consumption can represent up to 40% of overall building energy expenditures. In order to curb this trend, government policies such as the Leadership in Energy and Environmental Design (LEED) are promoting green HVAC through tax incentives. As a results, the correct design and integration and an HVAC system in a building can strongly affect its financial viability. New simulation capabilities can provide insights about the performance of an HVAC, and help improve its integration in the building, before even breaking ground on construction. In order to promote seamless coupling and change management at every stage of a project, 1D Heating Ventilation and Air Conditon system models and 3D building models need to be simulated in an integrated solution. This solution can include zonal 1D and detailed 3D representations of a building in order to investigate key performance indicators for energy consumption, thermal comfort and Interior Air Quality, and assess present and even future usage scenarios. In this paper, we will demonstrate how to size and integrate an HVAC system in a building, using Modelica based system models, focusing on thermal comfort and IAQ. We will first make use of fast turn-around time 1D solutions, before finally demonstrating the advantages of fully coupled 1D system modelling and 3D Computation Fluid Dynamics (CFD) with integrated state of the art comfort modelling to balance HVAC energy efficiency and IEQ.
HVAC, Building, Thermal Comfort, Indoor Air Quality
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