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Prediction of Cooling-Drag using CFD

Hägerström, Fredrik (2010) In ISRN LUTMDN/TMHP--10/5221--SE
Department of Energy Sciences
Abstract
As passenger cars emissions standards are tightened manufacturers are forced to cut the cars fuel consumption. This can be done in various ways and one of these is to improve a cars aerodynamic attributes, and above all the car's drag coefficient. A part of the car's total drag is from the air passing through the car's engine compartment and cooling system. The air to slow down, rerouted, and eventually mixed with the surrounding air as it passes and exits the engine compartment, and all these operations generate drag. This drag contribution is called the “cooling-drag”. That is, the increased total drag when the radiator grille of the car is open.
The objective of this thesis is to evaluate and propose changes CAE methods at VCC to... (More)
As passenger cars emissions standards are tightened manufacturers are forced to cut the cars fuel consumption. This can be done in various ways and one of these is to improve a cars aerodynamic attributes, and above all the car's drag coefficient. A part of the car's total drag is from the air passing through the car's engine compartment and cooling system. The air to slow down, rerouted, and eventually mixed with the surrounding air as it passes and exits the engine compartment, and all these operations generate drag. This drag contribution is called the “cooling-drag”. That is, the increased total drag when the radiator grille of the car is open.
The objective of this thesis is to evaluate and propose changes CAE methods at VCC to predict the cooling-drag of a car and if possible make suggestions to how it could be decreased.
Wind tunnel tests has been performed of a Ford Mondeo and a range of commercial software is available. These wind tunnel data will be compared with results from CFD calculations and thus validating the CFD calculations.
In this thesis a CAD model of a Ford Mondeo has been adapted to mimic the car that has been used in wind tunnel tests and been modified in order to evaluate the causes of cooling-drag. From this model, a computational grid has been generated and subsequently imported into the simulation software in which the fluid governing equations and turbulence models are solved.
The following fields that can contribute to the cooling-drag have been tested in this thesis: cooling package design, higher detail level on the car's tires and modified turbulence model modulation near the walls. Conclusions have been drawn from these variations that contribute to an increased understanding of the causes of a car's cooling-drag and recommendations for changes in the current VCC CAE methods to increase its accuracy in predicting the cooling-drag using CFD of a car. (Less)
Please use this url to cite or link to this publication:
author
Hägerström, Fredrik
supervisor
organization
year
type
H1 - Master's Degree (One Year)
subject
keywords
cooling-drag cooling package design turbulence model
publication/series
ISRN LUTMDN/TMHP--10/5221--SE
language
English
id
2543723
date added to LUP
2012-05-23 14:06:18
date last changed
2012-05-23 14:06:18
@misc{2543723,
  abstract     = {As passenger cars emissions standards are tightened manufacturers are forced to cut the cars fuel consumption. This can be done in various ways and one of these is to improve a cars aerodynamic attributes, and above all the car's drag coefficient. A part of the car's total drag is from the air passing through the car's engine compartment and cooling system. The air to slow down, rerouted, and eventually mixed with the surrounding air as it passes and exits the engine compartment, and all these operations generate drag. This drag contribution is called the “cooling-drag”. That is, the increased total drag when the radiator grille of the car is open.
The objective of this thesis is to evaluate and propose changes CAE methods at VCC to predict the cooling-drag of a car and if possible make suggestions to how it could be decreased.
Wind tunnel tests has been performed of a Ford Mondeo and a range of commercial software is available. These wind tunnel data will be compared with results from CFD calculations and thus validating the CFD calculations.
In this thesis a CAD model of a Ford Mondeo has been adapted to mimic the car that has been used in wind tunnel tests and been modified in order to evaluate the causes of cooling-drag. From this model, a computational grid has been generated and subsequently imported into the simulation software in which the fluid governing equations and turbulence models are solved.
The following fields that can contribute to the cooling-drag have been tested in this thesis: cooling package design, higher detail level on the car's tires and modified turbulence model modulation near the walls. Conclusions have been drawn from these variations that contribute to an increased understanding of the causes of a car's cooling-drag and recommendations for changes in the current VCC CAE methods to increase its accuracy in predicting the cooling-drag using CFD of a car.},
  author       = {Hägerström, Fredrik},
  keyword      = {cooling-drag cooling package design turbulence model},
  language     = {eng},
  note         = {Student Paper},
  series       = {ISRN LUTMDN/TMHP--10/5221--SE},
  title        = {Prediction of Cooling-Drag using CFD},
  year         = {2010},
}