Increased surface temperature at critical heat flux for single water droplet impact with alcohol additives

Abstract

Elevating the critical heat flux limit during droplet impact cooling is advantageous for the thermal management of various high-power equipment. This study presents the experimental observation that the surface temperature at the critical heat flux point decreases with droplet impact velocity. The findings also demonstrate that low-carbon alcohol additives at small concentrations markedly increase the critical heat flux temperature of an impacting water droplet. In particular, the critical heat flux temperatures of dilute alcoholic solution droplets at higher impact velocities exceed those of pure water droplets at lower impact velocities within the present test range. Accordingly, low-carbon alcohol additives at low volume fractions can assure high heat transfer rates at large Weber numbers while also reducing the detrimental effect of impact velocity on the critical heat flux temperature. The significantly increased critical heat flux temperature associated with low-carbon alcohol additives is supposed to be considerably favorable for efficient heat dissipation of high-heat-flux electronic components.