Research on breakup length and atomization characteristics of the swirl liquid sheet in perforation disintegration mode

Pressure swirl nozzles usually operate in aerospace or aviation engines by discharging a swirl liquid sheet. Understanding the disintegration characteristics of the swirl liquid sheet is beneficial to control the combustion instability. In this study, a swirl liquid sheet was injected into the atmosphere. The whole breakup process was numerically simulated by Gerris, an open-source code that anticipates gas-liquid interface using the volume of fluid approach. With the increase in Reynolds number, there were three distinct disintegration modes including rim mode, perforation mode, and wave mode. Then, a perforation disintegration model (PDM) was proposed to predict the droplet size of the perforation disintegration mode. The droplet sizes predicted by PDM are consistent with the numerical results with an average error of 11.09%. A breakup length model (BLM) was also proposed for the swirl liquid sheet using energy conservation. The breakup length results of BLM are in good agreement with the numerical simulation results with an average error of 10.97%. Moreover, with the increase in the liquid surface tension coefficient, the droplet size of the swirl liquid sheet atomization gradually increases. With the increase in liquid density, the droplet size gradually decreases, but the trend of decrease is not obvious.