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Cooling Inlet Aerodynamic Performance and System Resistance
Technical Paper
2002-01-0256
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
This report is a contribution to the understanding of inlet aerodynamics and cooling system resistance. A characterization of the performance capability of a vehicle front-end and underhood, called the ram curve, is introduced. It represents the pressure recovery/loss of the front-end subsystem - the inlet openings, underhood, and underbody. The mathematical representation, derived from several experimental investigations on vehicles and components, has four basic terms:
- Inlet ram pressure recovery; free-stream energy recovered when the vehicle is moving
- Basic inlet loss; inlet restriction when the vehicle is stationary
- Pressure loss of the engine bay
- Engine bay-exit pressure
Not surprisingly, the amount of frontal projection of radiator area through the grille, bumper and front-end structure (called projected inlet area), and flow uniformity play a major role in estimating inlet aerodynamic performance. One experimental investigation demonstrated that the ram curve is independent (essentially) of the fan/shroud system installed in the vehicle. Another experiment showed that the engine-bay pressure loss (which includes the interference of the underhood package on fan performance) might be small compared to the other resistances. The universal characteristic map of fan and system performance can be used to track airflow changes during early vehicle design tradeoff studies.
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Citation
Williams, J., Karanth, D., and Oler, W., "Cooling Inlet Aerodynamic Performance and System Resistance," SAE Technical Paper 2002-01-0256, 2002, https://doi.org/10.4271/2002-01-0256.Also In
References
- Kanefsky, P. Nelson, V. A. Ranger, M. “A Systems Approach to Engine Cooling Design” The 44th L. Ray Buckendale Lecture SAE SP-1541 November 1999
- Caltrider, J. L. Davis, F. V. Madhavan, R. Veling, T. “Impact of Computer Aided Engineering on Ford Light Truck Cooling Design and Development Processes” SAE 931104
- Williams, Jack Vemaganti, Guru “CFD Quality - A Calibration Study for Front-End Cooling Airflow” SAE 980039 February 1998
- Hawes, S. P. “Improved passenger car cooling systems” SAE 760112 February 1976
- Oler, J. W. Roseberry, C. M. Jordan, D. P. Williams, J. “Ram Recovery Coefficient Correlations for Automotive Cooling Airflows” SAE 910309 February 1991
- Eichlseder, W. Raab, G. Hager, J. Raup, M. “Use of Simulation Tools with Integrated Coolant Flow Analysis for the Cooling System Design” SAE 971815 May 1997
- Williams, Jack “An Automotive Front-End Design Approach for Improved Aerodynamics and Cooling” SAE 850281 February 1985
- Olson, M. E. “Aerodynamic Effects of Front End Design on Automobile Engine Cooling Systems” SAE 760188 February 1976
- Hucho, W. “Aerodynamics of Road Vehicles” fourth SAE 1998
- Schaub, U. W. “A Wind Tunnel Study of Ram Air Effects on the Air Side Cooling System Performance of a Typical North American Passenger Car” NRC of Canada report LTR-ENG-81 July 1978
- Schaub, U. W. Charles, H. N. “Ram Air Effects on the Air Side Cooling System Performance of a Typical North American Passenger Car” SAE 800032 February 1980
- Acre, James. A. “Application of Vehicle Characteristic Curves to Determine Vehicle Cooling Airflow Rates” SAE TOPTEC Conference Presentation February 2000
- “Laboratory Methods of Testing Fans for Rating” ANSI/ASHRAE Standard 51-1985 1986
- Williams, J. E. Hackett, J. E. Oler, J. W. Hammer, L. “Water Flow Simulation of Automotive Underhood Airflow Phenomena” SAE 910307 February 1991
- Seddon, J. Goldsmith, E. L. “Intake Aerodynamics” American Institute of Aeronautics and Astronautics, AIAA Education Series 1985
- Schaub, U. W. Private communication November 2001
- Pritchard, R. “Experimental Correlation of Ram Pressure to Surface Static Pressure using a Cylinder in Cross Flow” Masters Degree Thesis Texas Tech U., M. E. Department May 2001
- Verner, D. G. “General Ram Correlations for Automobiles” Masters Degree Thesis Texas Tech U., M. E. Department May 2000
- Walter, J. D. “Characterizing Underhood Cooling Components for Analysis and Simulation” Masters Degree Thesis Texas Tech U., M. E. Department August 1998