Experimental evaluation of individual effects of water mist spray characteristics on thermal radiation attenuation using twin-fluid nozzles with full-cone spray pattern

In this study, the effects of water mist spray characteristics on thermal radiation attenuation were experimentally investigated using five types of external and internal mixing twin-fluid nozzles with a full-cone spray pattern. To the best of our knowledge, this may be the first attempt to experimentally examine the separate effects of water mist spray characteristics on thermal radiation attenuation. Water and air supply pressures were measured, and their values were 1.3-55.5 and 29.8-316 kPa, respectively. The Sauter mean diameter and volume median diameter of the water mist were measured to be 20-99 mu m and 21-108 mu m, respectively. The spray angle and width of the water mist were approximately 20 degrees and 110 mm, respectively. The thermal radiation attenuation afforded by the water mist discharged from the twin-fluid nozzle increased with increasing water and air flow rates and decreasing droplet sizes. Within the experimental range, the thermal radiation attenuation was approximately 6.9%-28.4%. Based on experimental data, the effects of the water flow rate and droplet size on thermal radiation attenuation were examined independently. The dependence of the thermal radiation attenuation on the droplet size was greater than that on the water flow rate.