Simulation of viscoelastic droplet formation in T-type microchannels using OpenFOAM

Microdroplet formation has been widely used in 3D printing, additive manufacturing, chemical synthesis and other fields. Comprehensive understanding for the microdroplet formation is necessary for process optimization of the above-mentioned fields. In this paper, the Giesekus (GK) model is used to simulate the formation of viscoelastic droplet in T-type microchannels based on OpenFOAM. The effects of liquid phase elasticity, viscosity and channel wall wettability on the formation of viscoelastic droplet were investigated by changing the relaxation time of the dispersed phase, polymer viscosity and wall contact angle. The pressure characteristics, droplet final lengths and detachment time were compared under different operating conditions. The simulation results describe the effect of fluid parameters on droplet formation in the form of pressure, which is used to supplement the shortcomings of existing experiments in stress. The results show that the elasticity hinders droplet breakup during the stretching stage. As the polymer viscosity increases, there is a significant increase in the elasticity of the droplet, which prevents the droplet filaments from stretching and breaking, resulting in a slower frequency of droplet formation. Moreover, the influence of wall contact angle and fluid flow rate on the formation of viscoelastic droplets in T-shaped microchannel is also observed. It is found that the wall contact angle also has an impact on the final droplet length, which cannot be ignored.