This content is not included in your SAE MOBILUS subscription, or you are not logged in.
A Numerical Investigation of Dampening Dynamic Profiles for the Application in Transient Vehicle Thermal Management Simulations
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 01, 2014 by SAE International in United States
Annotation ability available
As computational methodologies become more integrated into industrial vehicle pre-development processes the potential for high transient vehicle thermal simulations is evident. This can also been seen in conjunction with the strong rise in computing power, which ultimately has supported many automotive manufactures in attempting non-steady simulation conditions.
The following investigation aims at exploring an efficient means of utilizing the new rise in computing resources by resolving high time-dependent boundary conditions through a series of averaging methodologies. Through understanding the sensitivities associated with dynamic component temperature changes, optimised boundary conditions can be implemented to dampen irrelevant input frequencies whilst maintaining thermally critical velocity gradients.
A sub-module derived from real vehicle geometry was utilised to evaluate a series of alternative averaging schemes (consisting of steady-state CFD points) in comparison to full CFD transient conditions. The size and simplicity of the model additionally allowed for an easy transition to the heavy computationally demanding unsteady conditions. The input data for both averaging schemes and full transient conditions were derived from the real vehicle driving profiles experimentally obtained on the Nuerburgring test track.
Qualitative analysis was conducted between the alternative schemes and full transient data in order to isolate the effects of dampening boundary conditions on consequent component temperatures. It was found that a weighted moving average can be optimal in resolving the high frequency changes whilst maintaining the average energy balance across under body components. The reactivity of the averaging schemes was dependent on the sampling rates in combination with the process of neutralising the inherent lag effects. Both these parameters had a significant effect on the time dependent results.
In order to isolate the effectiveness of the averaging schemes on the “warm-up phase”, multiple laps were conducted to locate the point at which temperature stabilisation occurs. Additionally the effect of incorrect initial component temperature was explored through evaluating the time taken to thermal stabilisation. It was found that under differing thermal conditions the time taken to thermal stabilisation was relatively constant regardless of the initialisation temperature.
The investigation explored the influence of improving the simulation accuracy by increasing the quantity of steady-state CFD points in locations of high velocity amplitudes over a short time period. Additionally the opposite was explored in regions of low velocity amplitude, in extended time phase. A relationship was found between the velocity gradient and the quantity of steady-state CFD points for component temperature. Through the findings of the investigation a Fourier type algorithm was exploited to further improve turnover efficiencies.
CitationHaehndel, K., Pere, A., Frank, T., Christel, F. et al., "A Numerical Investigation of Dampening Dynamic Profiles for the Application in Transient Vehicle Thermal Management Simulations," SAE Technical Paper 2014-01-0642, 2014, https://doi.org/10.4271/2014-01-0642.
- Srinivasan , K. , Woronowycz , G. , Zabat , M. , and Tripp , J. An Efficient Procedure for Vehicle Thermal Protection Development SAE Technical Paper 2005-01-1904 2005 10.4271/2005-01-1904
- Pryor , J. , Pierce , M. , Fremond , E. , and Michou , Y. Development of Transient Simulation Methodologies for Underhood Hot Spot Analysis of a Truck SAE Technical Paper 2011-01-0651 2011 10.4271/2011-01-0651
- Reister , H. and Bauer , W. Simulation Process of the Heat Protection of a Full Vehicle SAE Technical Paper 2012-01-0635 2012 10.4271/2012-01-0635
- Weidmann , E. , Binner , T. , and Reister , H. Experimental and Numerical Investigations of Thermal Soak SAE Int. J. Mater. Manuf. 1 1 145 153 2008 10.4271/2008-01-0396
- Tentner , A. , Froehle , P. , and Wang , C. Modeling and Analysis of Transient Vehicle Underhood Thermo-Hydrodynamic Events Using Computational Fluid Dynamics and High Performance Computing SAE Technical Paper 2004-01-1511 2004 10.4271/2004-01-1511
- Franchetta , M. , Bancroft , T. , and Suen , K. Fast Transient Simulation of Vehicle Underhood in Heat Soak SAE Technical Paper 2006-01-1606 2006 10.4271/2006-01-1606
- Haehndel , K. Development of Exhaust Surface Temperature Models through the numerical prediction of 1D/3D CFD Coupling Thesis RMIT Melbourne 2010
- Haehndel , K. , Frank , T. , Christel , F. , and Abanteriba , S. An Innovative Approach to Race Track Simulations for Vehicle Thermal Management SAE Int. J. Passeng. Cars - Mech. Syst. 6 3 1564 1576 2013 10.4271/2013-01-9121
- Disch , M. , Widdecke , N. , Wiedemann , J. , Reister , H. et al. Numerical Simulation of the Transient Heat-Up of a Passenger Vehicle during a Trailer Towing Uphill Drive SAE Technical Paper 2013-01-0873 2013 10.4271/2013-01-0873
- Kaushik , S. Thermal Management of a Vehicle's Underhood and Underbody Using Appropriate Math-Based Analytical Tools and Methodologies SAE Technical Paper 2007-01-1395 2007 10.4271/2007-01-1395
- Haehndel , K. , Frank , T. , Christel , F. , Spengler , C. et al. The Development of Exhaust Surface Temperature Models for 3D CFD Vehicle Thermal Management Simulations Part 1 - General Exhaust Configurations SAE Int. J. Passeng. Cars - Mech. Syst. 6 2 847 858 2013 10.4271/2013-01-0879
- Pere , A. Best Practices for Modelling Full Vehicle Configurations in CFD Thesis RMIT Melbourne 2013
- Bender , T. , Hoff , P. , and Kleemann , R. The New BMW Climatic Testing Complex - The Energy and Environment Test Centre SAE Technical Paper 2011-01-0167 2011 10.4271/2011-01-0167