Unsteady Thermal Management Simulations for a Passenger Vehicle using 1D and 3D Tools
Examensarbete för masterexamen
Automotive engineering (MPAUT), MSc
This work develops a coupled 1D-3D computational tool for analyzing conjugate heat transfer in the engine bay of a passenger vehicle. 1D thermal models of powertrain in conjunction with detailed 3D models of ow structures can provide a powerful means to correctly capture the physics of the system while keeping the computational cost reasonably low. To the authors' best knowledge, simultaneous coupling of 1D and 3D computational tools has not been applied to modelling thermal interaction in the vehicle powertrain before. Thus, this work constitutes a first step towards performing such coupled simulations and analyzing their outcome. The present study builds on a 1D model of a powertrain cooling system, built in GT-SUITE software, by adding a comprehensive lubrication circuit and mean value engine model to monitor the time dependent temperatures of oil and engine solids. A 3D model of natural convection & radiation in the engine bay was built in STAR-CCM+ where the primary boundaries for heat transfer between the surrounding air in the underhood region and engine solids were defined. The two models were run simultaneously and data were exchanged for the surface temperatures of the primary engine components as well as the heat transfer rate between these components and the engine bay surroundings. The developed tool was used to study the variation of mass averaged oil temperature over a customized driving cycle. This cycle consists of the recently introduced Worldwide harmonized Light duty driving Test Cycle (WLTC) with additional shut-down periods during which the car was assumed to be parked in a quiescent environment. The delivered numerical procedure proved to be an effective approach for such drive cycles. The present work can thus serve as a solid basis for implementing more advanced thermal management models in the future.
Farkostteknik , Grundläggande vetenskaper , Hållbar utveckling , Energi , Transport , Vehicle Engineering , Basic Sciences , Sustainable Development , Energy , Transport