Dust and exhaust emission management in railway tunnels during grinding operations with a 1D/3D simulation approach

A rail grinder is a track maintenance vehicle used to restore the profile and remove irregularities from rails. It is used to extend rails’ life and improve the train performance. When operating in a tunnel, the the grinder emits exhaust gases and dust, making the tunnel an unsafe environment for workers. Simulation can play a role designing and operating an efficient ventilation system. This workflow puts together a fast and quasi-real time 1D workflow with a detailed 3D CFD simulation that estimates the required time for the dust and exhaust ratio to drop below an acceptable threshold, but also the energy consumption required for ventilation system. This work also shows how quick and easy it is to test different scenarios without requiring high-level simulation expertise on the end-user side.

Presenter: Evangelos ANTONIOU, Dassault Systèmes

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HVAC Vent Noise Simulation

Heating, Ventilation, and Air Conditioning (HVAC) are essential for the comfort of vehicle occupants. However, a poorly designed HVAC system may suffer from many acoustic issues. One of them is an annoying sound produced by the turbulent air flow through the vents that connect the HVAC system to the cabin. Thus, when a new vent design is proposed during the concept phase of vehicle development, it is necessary to check whether its aeroacoustic behavior is acceptable. Since physical prototypes are only available at a later stage, Computational Aeroacoustics Analysis (CAA) is the only way to do this already during the concept phase. In this presentation, we digitize a well-established test procedure to obtain a CAA method for HVAC vents. Two blind tests show that this CAA method accurately reproduces the results of the original physical test if the underlying geometry model meets some specific requirements. Furthermore, we indicate how detailed analysis of the simulation results helps to improve the aeroacoustics of the HVAC system.

Presenter: Dirk KEHRWALD, Stellantis

Replay

Aeroacoustic analysis of a centrifugal fan cooktop extractor system with comparison to real measurement data

We present computational aeroacoustics simulations performed with SIMULIA PowerFLOW Lattice Boltzmann CFD solver of our leading BORA Professional 3.0 cooktop extractor system with an integrated centrifugal fan. We compare the results with microphone probe measurement data from our in-house anechoic chamber in the frequency range from 100Hz up to 8kHz. Furthermore, we investigate the results with the Flow Induced Noise Detection (FIND) module from SIMULIA PowerACOUSTICS for the frequencies 500Hz, 1kHz and 5kHz to identify noise sources. The first simulation serves as our baseline simulation, where we analyze flow patterns, identify noise sources and compare it to our measurement data. With further simulations we try to optimize the acoustic signals to better fit the measurement data through fine-tuning the simulation by changing the thickness of the Acoustic Porous Medium within the spiral of the fan and enabling the Wall Acoustic Absorption for the plastic parts. The baseline simulation already shows a good agreement with the overall trend but overpredicting the amplitude in the range from 200Hz – 2.5kHz by around 5dB(A). Changing the thickness of the Acoustic Porous Medium slightly increases the amplitude in the range of 2kHz – 8kHz but shows a better fit in general. Introducing Wall Acoustics Absorption shows the best result in the frequency range from 100Hz-3kHz but absorbs too much energy in the frequency range from 3kHz – 10kHz. However it shows the best fit in the overall frequency range.

Presenter: Matthias THALHAMMER, Bora Vertriebs GmbH & Co. KG

Aerodynamic Development for the 2026 Olympic Winter Games - System Coupling of a 1D-Mathematic Model and 3D SIMULIA PowerFLOW® Simulation

Objective of the research institute FES is to develop equipment for Olympic sports such as canoeing, cycling, sailing, bobsleighing, skeleton, skiing and snowboarding. Therefore, the FES provides gear and equipment solely for the German national teams. One of the institute's core competences is to optimise the interaction of athletes and their equipment. Utilisation of state-of-the-art simulation tools is just one key component in developing sports equipment. Starting from sports specific energy balances, aerodynamic simulations play a crucial role in sports. Moreover, simulation is the most innovative tool in development of summer and winter sports. Simulation helps to understand different competition situations including looking into athlete's anthropometry, clothes, environmental conditions and so on. In this presentation, system coupling of a sports specific mass point model with an aerodynamic CFO analysis in PowerFLOW will be shown. System coupling was an essential tool for the success during the last Winter Olympic games in Peking. How did simulation help to win medals in the past and which sports are actively developed for the Olympic games 2024 using PowerFLOW?

Presenter: Christoph FISCHER, Institut für Forschung und Entwicklung von Sportgeräten – FES

Validation of the Lattice-Boltzmann solver PowerFLOW® for the simulation of stirred tank reactor

In the medical, pharmaceutical, cosmetic and food industries, stirred tank reactors (STRs) are commonly used for to initiate or accelerate particular biological and chemical processes. As research in all these fields progresses and new medicines have to be "engineered", reactors design and the flow in the reactor itself increase in complexity. Fluid Digital Reactor Twins could help gain more insights into these vital processes, by analyzing the flow behaviour in the reactor for predicting the best conditions fitting a particular process. This with the idea to guarantee a successful reaction and avoid culture losses, due to the high sheer forces or too high local temperatures in the reactor. This explains the growing interest in fast and accurate numerical simulations for this type of application.
This paper validates the use of the lattice Boltzmann solver PowerFLOW® for the simulation of a baffled tank reactor stirred by a simple Rushton turbine. A grid dependency study is carried out for a single-phase water flow, analysing the velocity profiles in the radial and axial direction and the power number. Air injection for different regimes is then considered using Lagrangian particle tracking and the resulting gas volume fraction profiles are compared with both experimental [1] and Navier-Stokes simulations [2].

Presenter: Daniel MUTLYASHKI, Dassault Systèmes

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Investigation on the Ventilation Drag of HDV Wheels

The aim of the presented work is to investigate the ventilation drag of a European tractor-trailer with different wheel configurations using CFD. To define a robust method for quantifying the influence of the ventilation drag numerically, a validation study of the CFD prediction capabilities was performed. For this purpose, measurements of a generic tractor-trailer model were undertaken in the Model Scale Wind Tunnel of the University of Stuttgart. The investigations give insight into the involved flow phenomena and the resulting ventilation drag. They furthermore allow the consolidation of the used CFD procedure. Finally, CFD simulations were done to assess the contribution of ventilation drag to the total aerodynamic drag of a HDV.

Presenter: Carlos PEIRÓ FRASQUET, FKFS Forschungsinstitut für Kraftfahrwesen und Fahrzeugmotoren Stuttgart

Thermal Behavior of Vehicle Seats – Using Simulation to enhance Thermal Comfort

One of the main Transportation & Mobility (T&M) business drivers is the creation of novel customer experiences. No longer are customers just happy with travelling from point A to point B. They want to do so while experiencing a unique feeling in their vehicle. A major component of this is passenger thermal comfort. This well-being can be tuned through, for instance, the use of air conditioning or heating during hot or cold days, respectively. The most direct approach to satisfy passenger thermal comfort is to blow this cool or hot air through the interface between passenger body and vehicle seat, thereby creating a thermally regulated vehicle seat. In the past, design of temperature controlled vehicle seats, which includes the seat structure, foam layers, and fans, has taken place entirely on real-world thermal test benches. This approach is limiting though: one cannot access the full temperature or velocity field in the test domain. The current talk aims to present a first-of-its-kind simulation workflow using a PowerFLOW-PowerTHERM coupled simulation to assess the thermal behavior of a vehicle seat. Specifically, the simulation models the cool down of a seat’s leather layer, which has an initial temperature of 65°C, using ambient air and is validated against experimental results. The simulation opens up doors to more complex simulation scenarios, such as sequential coupling to a structural simulation to obtain a deformed seat, the assessment of comfort using a human comfort model, and/or an in-situ vehicle simulation of the seat.

Presenter: Thorsten HANS, LEAR Corporation & Faron HESSE, Dassault Systèmes

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