Role of Water Temperature in Case of High Mass Flux Spray Cooling of a Hot AISI 304 Steel Plate at Different Initial Surface Temperatures

In case of spray evaporative cooling, the heat transfer rate is controlled by various factors such as droplet renewal rate, Leidenfrost effect, and the rate of heat extraction by each droplet. In the current work, in case of high mass flux spray cooling (~55 kg/m ² s), the heat extraction rate is tried to enhance by increasing the water temperature. Furthermore, from different initial surface temperatures (300°C-800°C), cooling experiments were conducted at various water temperatures (10°C-50°C). The surface temperatures and heat fluxes are calculated using an inverse heat conduction software (INTEMP). The result reveals that with the increasing water temperature, the heat removal rate rises in both transition and nucleate boiling regimes due to the increment of latent heat extraction time during the residence period of the water droplet on the hot plate. The maximum percentage in the enhancement of initial heat flux, average heat flux (AHF), and critical heat flux (CHF) are achieved in the nucleate boiling regime ( < 600°C); however, the increment in the transition boiling regime is also significant.