The Development of Exhaust Surface Temperature Models for 3D CFD Vehicle Thermal Management Simulations Part 2 - Exhaust Acoustic Silencer Configurations

Haehndel, Kristian; Jefferies, Anthony; Schlipf, Markus; Frank, Torsten; Christel, Frieder; Abanteriba, Sylvester

doi:10.4271/2014-01-0646

Cited by 3 publications

(5 citation statements)

References 5 publications

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“…Schlipf improved the method further by including the heat transfer effects inside an acoustic silencer [31]. The results showed good resolution of the local thermal gradients on the surface of the acoustic silencers [18]. The methodology was advanced further by DeVos via the development of a process to calculate the heat rate augmentation within the turbocharger system [34].…”

Section: State Of the Artmentioning

confidence: 99%

Hybrid model for exhaust systems in vehicle thermal management simulations

Ahmed

Rottengruber

Full

2022

Automot. Engine Technol.

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Using Vehicle Thermal Management (VTM) simulations to predict the thermal load experienced by components is a popular method within the automotive industry. The VTM simulation approach is fast becoming equivalent to conducting thermal load tests with prototypes for vehicles powered by internal combustion engines. This is especially true in the early development phase of the vehicle. The accuracy of the VTM simulations plays a pivotal role at them being accepted as an eventual replacement for physical testing. The correct prediction of thermal loads in VTM simulations depends on a multitude of different parameters, but the modelling of the exhaust system plays a central role in it. This is because the exhaust gas, and with it the exhaust system, is the primary source of heat in a vehicle powered by an internal combustion engine. The developed approach not only needs to be accurate but also modular enough to allow for different exhaust configurations to be tested. It also needs to be capable of integration into any VTM simulation workflow while maintaining an industrially acceptable turnaround time. This paper explores a new methodology to achieve these requirements. A 1D/3D hybrid approach to exhaust system modelling is presented. In this, the components that have an enthalpy change of the exhaust gas, such as the turbocharger, have been modelled as 1D and simple components such as pipes have been modelled in 3D. This has the advantage of combining the speed of 1D simulations with the spatial accuracy of 3D simulations. The method uses a unique three-code co-simulation technique for full vehicle VTM simulations. The coupling is between a 3D CFD software, a 1D simulation tool, and a Finite Element based thermal solver. The methodology was validated against experimental data for multiple loadcases. The results show good agreement with experiment within acceptable tolerances.

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Section: State Of the Artmentioning

confidence: 99%

Hybrid model for exhaust systems in vehicle thermal management simulations

Ahmed

Rottengruber

Full

2022

Automot. Engine Technol.

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“…where, u in and T max are unsteady velocity and maximal pulsating velocity, respectively; T in and T max are unsteady temperature and maximal pulsating temperature, respectively; u s and T s are mean velocity and, mean temperature, respectively; v is pulsating frequency. On the basis of steady state simulation under the condition of full load vehicle uphill, 13 the time step of unsteady simulation is determined according to the engine speed, and the fluctuating velocity and temperature of exhaust gas are determined according to the exhaust law of the engine at the corresponding speed. The subroutine U File (UDF), which can be called by Star-CD (FLUENT) software, 28,29 is written as the boundary conditions of unsteady simulation, respectively.…”

Section: Boundary Conditionsmentioning

confidence: 99%

“…On the basis of steady state simulation under the condition of full load vehicle uphill, 13 the time step of unsteady simulation is determined according to the engine speed, and the fluctuating velocity and temperature of exhaust gas are determined according to the exhaust law of the engine at the corresponding speed. The subroutine U File (UDF), which can be called by Star-CD (FLUENT) software, 28 , 29 is written as the boundary conditions of unsteady simulation, respectively.…”

Section: Computational Modelmentioning

confidence: 99%

“…In fact, in addition to working energy, about 70% of the engine energy needs to be protected by an effective thermal management system to achieve energy saving, and to improve the thermal comfort requirements of passengers. 1,[11][12][13] The high temperature of engine exhaust will affect the exhaust system components and their surrounding environment by heat dissipation. When the parts are too close to the high temperature exhaust system, these components will overheat.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Predicting unsteady heat transfer effect of vehicle thermal management system using steady velocity equivalent method

et al. 2021

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In the process of vehicle development, the unsteady simulation of thermal management system is very important. A 3D-CFD calculation model of vehicle thermal management is established, and simulations were undertaken for uphill with full loads operations condition. The steady results show that the surface heat transfer coefficient increases to the quadratic parabolic relationship. The unsteady results show that the pulsating temperatures of exhaust and external airflow are higher than about 50°C and lower than 10°C, respectively, and the heat dissipating capacities are higher than about 11%. Accordingly, the conversion equivalent exhaust velocity increased by 1.67%, and the temperature distribution trend is basically the same as unsteady results. The comparison results show that the difference in the under-hood should be not noted, and that the predicted exhaust system surface temperatures using steady velocity equivalent method are low less 10°C than the unsteady results. These results show the steady velocity equivalent method can be used to predict the unsteady heat transfer effect of vehicle thermal management system, and the results obtained by this method are basically consistent with the unsteady results. It will greatly save computing resources and shorten the cycle in the early development of the vehicle thermal management system.

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