An Aerodynamic Look at Automotive Radiators

An aerodynamic approach to improving liquid-to-air heat exchanger fin design is described. Radiator fin models, 10 times size, are tested in a special low turbulence wind tunnel. Hot-wire anemometer techniques are used to measure air velocity profiles, boundary layer thickness, and turbulence within the fin passages. These data in turn are related to heat transfer coefficients. Visual studies of flows are also made, using smoke and china-clay. This system provides an understanding of how a compact fin surface performs and gives a basis for systematic design of heat exchangers. Application of the technique has led to significant improvements in radiator fin performance.