This report examines the aerodynamic drag and external interference of engine cooling airflow. Much of the report is on inlet interference, a subject that has not been discussed in automotive technical literature. It is called inlet spillage drag, a term used in the aircraft industry to describe the change in inlet drag with engine airflow. The analysis shows that the reduction in inlet spillage drag, from the closed front-end reference condition, is the primary reason why cooling drag measurements are lower than would be expected from free stream momentum considerations. In general, the free stream momentum (or ram drag) is the upper limit and overstates the cooling drag penalty. An analytical expression for cooling drag is introduced to help the understanding and interpretation of cooling drag measurements, particularly the interference at the inlet and exit. Empirical thrust coefficients, which represent the interferences, are introduced as a practical representation of the interaction to the exterior pressure distribution. Comparisons to experimental measurements on three vehicles are presented to illustrate the concepts.


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    Title :

    Aerodynamic Drag of Engine-Cooling Airflow With External Interference


    Additional title:

    Sae Technical Papers


    Contributors:

    Conference:

    SAE 2003 World Congress & Exhibition ; 2003



    Publication date :

    2003-03-03




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English


    Keywords :


    2003-01-0996 Aerodynamic Drag of Engine-Cooling Airflow With External Interference

    Williams, J. / Society of Automotive Engineers | British Library Conference Proceedings | 2003


    Aerodynamic drag of engine-cooling flow with external interference

    Williams,J. / Ford Motor,US | Automotive engineering | 2003



    Assessment of engine cooling performance by measurement of cooling airflow drag in aerodynamic wind tunnels

    Chometon,F. / Gillieron,P. / Conservatoire National des Arts et Metiers,FR et al. | Automotive engineering | 1998


    Assessment of Engine Cooling Performance by Measurement of Cooling Airflow Drag in Aerodynamic Wind Tunnels

    Chometon, F. / Gillieron, P. / SAE | British Library Conference Proceedings | 1998