Investigating the Scalability of Blue Whirl through Numerical Simulations

The blue whirl (BW) is a small, entirely blue, nearly soot-free flame first observed as it emerged from small-scale laboratory experiments of fire whirls (FW) burning liquid hydrocarbons on water (Xiao et al., PNAS, 2016). These BWs were approximately 2–2.5 cm wide and 6–8 cm tall, positioned just above the bottom surface. Recent progress in three-dimensional (3D) numerical simulations (Chung et al., Science Advances, 2020; Zhang et al., Computers and Fluids, 2018) has provided insights into the flame structure of BW. Here, we investigated whether the size of BW can be increased by changing the flame and flow parameters such as gravity, tangential inlet velocity, fuel supply rate, and radial inlet velocity. First, we conducted 3D simulations for these parameters, changing their values and investigating the effects on the BW. Then, according to the results, the limits for the flame regime change were found. Finally, staying within these limits, the four parameters were changed together, and the size of the BW was able to be increased approximately two to three times.