Dual synthetic jets controlled spray cooling: analysis and evaluation of heat transfer characteristics

Spray cooling is one of the most promising thermal management techniques; however, the efficiency of heat transfer and uniformity of conventional spray cooling require further enhancement. Dual synthetic jets enable flexible regulation of the spray flow field. This study employs CFD numerical simulations to investigate the effects of spray incident angle and dual synthetic jet driving amplitude on heat transfer performance at a heat flux of 20,000 W/m². The results reveal significant coupled effects between the spray incident angle and driving amplitude. At a 60° incident angle, dual synthetic jets most effectively merge and accelerate the spray droplets, forming a uniform and stable liquid film on the wall, which yields the lowest average wall temperature and optimal temperature uniformity. Meanwhile, increasing the driving amplitude enhances heat transfer, but this effect saturates beyond 0.6 m/s. Thus, practical applications require balancing flow control efficacy with power consumption. Within the investigated parameter ranges, the combination of a spray incident angle of 60° and driving amplitude of 0.6-1.0 m/s was found to provide the best heat transfer performance and temperature uniformity, elucidating the intrinsic mechanism of "vorticity control → droplet trajectory optimization → liquid film homogenization → heat transfer enhancement" in spray cooling under dual synthetic jet flow control.