Droplet ejection and the induced flowfield by microthermal bubble during growth/collapse process

Abstract

Numerical predictions on the entire process of droplet ejection by the growth/ collapse of an explosive microthermal bubble are achieved by first principle equations coupled with extended Rayleigh equations and Asai's pressure model. Supporting experiments such as the bubble size/shape image histories by high-speed camera and bubble-induced flowfield by microparticle image velocimetry are conducted for the impulsive and explosive process during the bubble growth/collapse. Excellent agreements between measurements and computations are obtained. Finally, the parameter studies on droplet ejections are conducted to seek the optimal designs for the ejection nozzle size, ink refilling chamber height, heat flux imposed, and the operating temperature.