Transonic Core-Disrupting Atomization of Banana Puree

We characterized the disintegration of non-Newtonian banana puree, revealing atomization mechanisms, instabilities, and droplet size distribution using a novel twin-fluid atomizer via CFD. We approximated banana puree viscosity, which drives droplet size, using the Herschel-Bulkley model. Simulations reveal that interfacial unsteadiness leads to a pulsing flow, which amplifies the growth of instabilities to produce smaller droplets. The pulsing nature of the system produces radial bursts, resulting in periodic fluctuations in droplet size moving axially through the system in a wave pattern. High strain rates at the nozzle exit and heat transfer from the steam contribute to reduction in puree viscosity by three orders of magnitude from the puree annulus to the primary atomization region. Furthermore, to investigate the effects of temporally viscosity variability, we assess and characterize the transition during a 10-fold step increase in banana puree viscosity.