Theoretical study of heat transfer enhancement mechanism of high alcohol surfactant in spray cooling

Abstract High alcohol surfactant could enhance spray cooling heat transfer, however the enhancing mechanism had not been identified. The present work used numerical model of spray cooling for high alcohol surfactant to specify the mechanism. After adding high alcohol surfactant, the spray characteristics and fluid properties were changed. The influences of these factors on heat transfer were studied, and it was found that the enhancement of heat transfer was mainly attributed to the effect of high alcohol surfactant on surface tension and droplet diameter: the decrease of surface tension and increase of droplet diameter made liquid film thicker and faster, and the lager liquid film thickness and velocity were helpful to take away the heat with a better flow. Both parameters were included in Weber number of droplets, and it could be concluded that high alcohol surfactant improved spray cooling performance mainly because of the increased Weber number. The dominant heat transfer mechanism was also discussed in the analysis of the effect of spray flow.