Experimental an‎d Numerical Study of dro‎plet Formation through Controlled Laminar Jet Breakup for Pharmaceutical Microencapsulation

9/3/2026 12:00:00 AM

In this dissertation, a laboratory-scale microencapsulation device was designed an‎d fabricated based on the controlled breakup of a laminar jet by applying the artificial disturbances. The primary focus of the research is on the control of dro‎plet formation, the production of monodisperse dro‎plets, an‎d the tuning of the device’s operating frequency. The study was conducted in three main stages. In the first stage, the non-Newtonian rheology of shear-thinning fluids an‎d its influence on jet breakup patterns an‎d flow regime transitions were numerically analyzed. The results indicate that increasing the non-Newtonian behavior index significantly alters the geometry of the necking an‎d detachment regions, which substantially reduces the formation of satellite dro‎plets. For example, under conditions of We = 6 an‎d Oh = 0.12, non-Newtonian rheology reduces satellite dro‎plet generation by approximately 8%. In the second stage, a novel method based on numerical simulation data an‎d discrete Fourier transform (DFT) was developed to identify the optimal frequency of artificial disturbances. Unlike simplified analytical models an‎d costly experimental trials, this method provides both higher accuracy an‎d lower cost. The validity of this approach was confirmed numerically an‎d experimentally. Using this method, the effects of parameters such as nozzle thickness an‎d fluid–nozzle contact angle on the optimal frequency were investigated. Findings show that reducing the nozzle outlet thickness under We = 6 an‎d Oh = 0.219 conditions can increase the optimal frequency by up to 70%. In the third stage, jet breakup an‎d the influence of applying artificial disturbances at the optimal frequency on dro‎plet characteristics were experimentally investigated using the fabricated device. Experimental results reveal that applying artificial disturbances at the optimal frequency reduces the stan‎dard deviation of dro‎plet diameter by 90%.

ميكرو قطره , ميكرو كپسول , سيالات غير نيوتوني , كنترل شكست جت , ناپايداري رايلي-پلاتو.

Microdro‎plet , Microcapsule , Non-Newtonian fluids , Control of jet breakup , Rayleigh–Plateau instability

Sepehr Mousavi

Majid siavashi