This paper describes a number of major modifications and alterations which have the potential to improve engine cooling systems for agricultural and industrial machines.
Of the passive augmentation schemes studied (packed-beds, gas/solid suspensions, and spray cooling), spray cooling is the only one which has potential for practical application, but only for intermittent use to avoid overdesign of conventional cooling systems.
The active augmentation techniques considered (surface scrapers, acoustic vibrations, and electric fields) involve additional system complexity. Acoustic vibrations and electric fields are not effective enough to justify their use in augmentating heat transfer in conventional cores. Recent laboratory tests of the surface scraping technique indicate that this method is very effective for improving heat transfer to air flows.
Studies of several new cooling arrangements indicate that direct contact heat exchangers and vaporization and condensation of engine coolant would probably not work as improved cooling systems. On the other hand, the following arrangements can reject large amounts of heat: tire heat exchangers, implement heat exchangers, and radiative-convective cooling panels. One or several of these arrangements could be attractive when used in combination with a smaller conventional heat exchanger.