Experimental study on heat-transfer characteristics of spray cooling for microchannel radiators

Spray cooling is an emerging and promising thermal-management solution with a wide range of applications. However, its application in engineering vehicles remains in the formative stage. In this study, an innovative spray-cooling system for engineering vehicles was proposed. The study, using thermocouples and visualisation methods, focused on how factors such as the spray angle, height, volume flow, nozzle aperture, and arrangement impact the uniformity of the surface temperature and heat-transfer enhancement. Optimal cooling was achieved using a spray angle of 60°, height of 90 mm, and flow rate of 500 l/h. Moreover, a nozzle aperture of 1.6 mm demonstrated superior efficiency in energy use and cooling. Higher temperature differentials (90–140 °C) enhanced the heat transfer but led to a 332.81 % increase in the non-uniformity of the surface temperature. Further, the study compared the spray-cooling efficiency between alumina nanofluids and deionised water. Alumina nanofluids with a 0.7 % mass fraction achieved a maximum heat-transfer coefficient of 450.6 W/(m2·K), 15.48 % higher than that of deionised water. Moreover, based on the experimental results, an empirical formula for enhanced heat transfer using spray cooling in construction machinery was developed, providing a valuable reference for guiding engineering practice. The proposed spray-cooling method, which exhibited a two- to three-time improvement over traditional air-cooled systems, holds considerable promise in the field of engineering vehicle applications.