The role of wettability of nonideal nozzle plate: From drop‐on‐demand droplet jetting to impact on solid substrate

The dynamics of drop‐on‐demand (DoD) droplet formation and subsequently impact on the solid substrate are investigated using a three‐dimensional (3‐D) multirelaxation‐time (MRT) pseudopotential lattice Boltzmann (LB) model. The wettability of nonideal nozzle plate and solid substrate is modeled by a geometric scheme within the LB framework. The dynamics of droplet formation are explored in a range of the inverse of Ohnesorge number Z = 4.95 , 11.57 , and 28.17 , and the Reynolds number R e = 39.6 , 58.9 , and 136.4 . For Z = 4.95 , no satellite droplet is observed and the wettability of nozzle plate greatly influences the velocity and length of jetting fluids. For Z = 11.57 , the filament breakup and recombination are observed. The moment of filament breakup is delayed with advancing contact angleθ Aincreasing. For Z = 28.17 with R e = 136.4 , the primary and satellite droplets could not be recombined withθ A = 30 ° andθ A = 60 ° which agree with the literature. Whereas withθ A = 90 ° , the recombination occurs. The dynamics of subsequent oscillating droplet impact on the substrate are similar to that of equilibrium droplet which could obtain high‐resolution printed features. Consequently, consideringθ A = 90 ° with large Z and R e numbers, the printable range could be extended which could help increase the printing frequency and boost the production outputs of inkjet printing. © 2018 American Institute of Chemical Engineers AIChE J , 64: 2837–2850, 2018