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Ram Air Effects on the Air Side Cooling System Performance of a Typical North American Passenger Car
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English
Abstract
A standard engine mounted cooling fan in a 1976 Ford Granada equipped with air conditioning and a 4.9ℓ (302 cu. in.) V-8 engine was performance-tested on the road and under wind tunnel generated ram air conditions. To achieve appropriate back pressure variation the whole engine bay was pressurized through use of remotely placed plant exhauster machinery.
System resistance was studied over a range of ram air conditions, and was shown to be composed of a ram air loss, a stationary vehicle front end loss, an engine bay blockage loss, and the radiator cooling air dynamic pressure, or face head. Ram air and cooling air flow caused engine bay pressure to be slightly positive relative to the ambient static pressure level.
Fan pressure-flow characteristics were measured for various fan speeds and three ram conditions. These were observed to correlate as one universal map. This universal characteristic together with the measured front end resistances and ram pressure was interpreted as series-operated fans consisting of a supercharging first stage and the cooling fan acting as a second stage. This model and the identified resistance mechanisms enables accurate performance prediction to be made.
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Authors
Citation
Schaub, U. and Charles, H., "Ram Air Effects on the Air Side Cooling System Performance of a Typical North American Passenger Car," SAE Technical Paper 800032, 1980, https://doi.org/10.4271/800032.Also In
References
- Stratton, D.G. Stringer, R.E. Taylor, S.R.G. “Engine Cooling System Design and Development” The Institution of Mechanical Engineers, Automobile Division, Proceedings 65–66 180 Part 2A 221 235
- Emmenthal, K.D. Hucho, W.H. “A Rational Approach to Automotive Radiator System Design” SAE 740088 1974
- Olson, M.E. “Aerodynamic Effects of Front End Design on Automobile Engine Cooling Systems” SAE 760188 1976
- Hay, N. Taylor, S.R.G. “The Effects of Vehicle Cooling System Geometry on Fan Performance” Conference on Fan Technology and Practice, Institution of Mechanical Engineers 18–19 April 1972 176 192
- Schaub, U.W. “On the Investigation of the Ram Air Effects on the Air Side Cooling System Performance of a North American Car,” National Research Council Ottawa, Canada DME/NAE Quarterly 3 October 1977 13 39