This article gives an overview how CFD is embedded today in the vehicle development process. It is shown how different CAE applications (here: according to thermo-management full vehicle functions) interacts with each other in many ways. The illustrated investigations showed that the operating conditions of a vehicle can be simulated with a sufficient accuracy by means of the simplified radiator model, where the pressure losses are modelled with porous media and the heat exchange with the help of an user subroutine. For the computation of the local heat transfer coefficients now a method exists, which permits a safe extrapolation far beyond the measured performance data. The influence of the non-uniformity of the coolant is very small according to the transferred heat (in the parts per thousand range). Therefore a neglect of the coolant's non-uniformity is permissible for the computation of the transferred heat. The modelling of the radiator tanks can be void. The non-uniformity of the air must be taken into account anyway. This is important for an accurate determination of ETD by coupling the three-dimensional engine compartment flow simulation with the one dimensional heat performance calculation. As well as the transferred heat performance the temperature distribution behind the radiator matrix is reproduced correctly. For an accurate temperature computation in the whole engine compartment the simulation of the coolant flow can become necessary, if the non-uniformity of the coolant affects the air temperature distribution behind the radiator matrix. Beside the radiator model the basis of a correct temperature distribution in the engine compartment is a proper fan model. Additional FEM analyses have to be performed if the determination of component temperatures in the engine compartment is aimed. By the means of component temperature calculations it can be seen the growing complexity by increasing progress of interacting CAE applications. In order to obtain the required accuracy and time limit for virtual prototyping, validation works like the radiator investigations are needed to enable a high process reliability for the employment of CAE in a modern vehicle development system.
Numerical methods, 3-dimensional
Numerische Verfahren, 3-dimensional
2002
14 Seiten, 15 Bilder, 12 Quellen
Aufsatz (Konferenz)
Englisch
Numerical methods, 3-dimensional
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