Computational and experimental studies on HEF 7100 two-phase spray cooling

Official URL: https://dx.doi.org/10.11159/icmfht24.143

Spray cooling is a highly efficient thermal management technique that has gained significant attention in various industrial and technological applications, such as power electronics, high-power lasers, and conversion systems. This investigation examines the effects of HEF 7100 spray parameters on the cooling process using numerical models and experimental approaches. We performed a series of tests to carefully examine the spray characteristics by progressively increasing the heat flux applied to a 2 cm2 hotspot. A comprehensive analysis of the effect of spray parameters was performed using two-phase curves, which depict the relationship between surface temperature and heat flux during the cooling process. Numerical simulations were performed to understand the fundamental principles underpinning heat transfer during multiple droplet impacts. It was found that the spray angle plays a substantial role in heat transfer, reducing heat transfer rates as the angle widens. This effect diminishes with increased spray pressure and temperature due to reduced surface wetting area and liquid film thickening. Interestingly, nozzle temperature has minimal influence on pressure-induced surface temperature reduction. Moreover, nozzle pressure enhances spray performance, with higher enhancement observed in single-phase regions (Twall < Tsat). This influence strengthens with decreasing spray angles and shorter spray distances in flat nozzles. The obtained boiling curves and heat transfer coefficients provide valuable data for designing and optimizing spray cooling systems, ultimately promoting the efficient dissipation of high heat fluxes in various engineering applications.