As an essential component of chip laboratories and microfluidic systems, micromixers are widely used in fields such as chemical and biological analysis. In this work, a square cavity micromixer with multiple structural parameters (baffles, obstacles, and gaps) has been proposed to further improve the mixing performance of micromixers. This study examines the comprehensive effects of various structural parameters on mixing performance. The impact of baffle length, obstacle length-to-width ratio, gap width, and obstacle shape on the mixing index and pressure drop were numerically studied at different Reynolds numbers (Re). The results show that the mixing index increases with baffle length and obstacle length-to-width ratio and decreases with gap width at Re = 0.1, 1, 10, 20, 40, and 60. The mixing index can reach more than 0.98 in the range of Re ≥ 20 when the baffle length is 150 μm, the obstacle length-to-width ratio is 600/100, and the gap width is 200 μm. The pressure drop of the microchannel is proportional to baffle length and obstacle length-to-width ratio. Combining baffles and obstacles can further improve the mixing performance of square cavity micromixers. A longer baffle length, larger obstacle length-to-width ratio, narrower gap width, and a more symmetrical structure are conducive to improving the mixing index. However, the impact of pressure drop must also be considered comprehensively. The research results provide references and new ideas for passive micromixer structural design.

Although there have been more studies on droplet formation under the control of electrostatic field in recent years, the studies on the relationship between composite droplet formation and electrostatic field are fragmented. In order to analyze the effect of electrostatic field on composite droplet formation, this paper numerically investigates the electro-hydrodynamics of the double emulsion in a double Y-shaped microchannel and experimentally verifies the applied phase interface capture method. Calculations are carried out using a model coupled with the phase field method and electrostatic field to analyze the interfacial evolution of double emulsions under different electric field strengths and to quantitatively study the droplet formation process. Four flow regimes different from previous studies were found: dripping regime, jetting regime, threading regime, and jetting-dripping transition regime, among which the formation frequency ( f ) of double emulsion droplets under the short jetting regime was up to 769 Hz. The eccentricity (ε) of droplets under the dripping regime was the smallest, with ε of 0.2, the coefficient of deformation (Defm) of the middle phase droplets was minimized to 0.05. It is observed that there is a linear relationship between Cam/Cao and CaE in the dripping regime, with the generation of multi-core double emulsion droplets. When Cam/Cao is greater than 14, the flow regime of the double emulsion in the channel is always threading regime, no matter how CaE is changed.

An implantable collamer lens (ICL) is a biocompatible artificial lens specifically designed to correct refractive errors in myopic patients with high precision and stability, but postoperative complications are observed after ICL implantation surgery. A novel ICL with drain channels is designed to improve the beneficial aqueous humor (AH) flow postoperatively and reduce the risk of visual impairment. This study analyzes the effects of conventional ICL, ICL with a central hole (Hole-ICL), and ICL with a drain channel (scICL) on AH flow. The impact of the geometric parameters of the drain channel in scICL on AH velocity and pupil flow rate is investigated. Additionally, a double-channel ICL (dcICL) is designed to analyze the impact of drain channel symmetry on AH flow. The results indicate the maximum velocities on the posterior chamber (PC) circle line are 2.24×10−6, 2.46×10−6, and 1.23×10−5 m/s for conventional ICL, Hole-ICL, and scICL in an up-facing eye, respectively. In both up-facing and horizontally facing eyes, the pupil flow rate in the scICL increase by 21% and 5.5%, respectively. The AH flow velocity reaches its maximum when the drain channel width is approximately 38% of the total scICL width and a concomitant proximity to the scICL thickness. When the width ratio and depth ratio of the dcICL are equal to zero (analogous to the scICL), the AH flow velocity and pupil flow rate reach their maximum. The scICL presented in this study improves the AH flow, reducing postoperative complications associated with ICL implantation and providing guidance for the clinical myopia treatment.

Accurately predicting the temporal and spatial distribution of intraocular drugs to enhance anti-glaucoma treatment efficacy remains a significant challenge in clinical ophthalmology. Developing more precise numerical models of intraocular drug transport holds substantial clinical value. This study establishes a model of intraocular drug transport, which includes the trabecular meshwork (TM), collector channels (CC), and uveoscleral outflow pathway, and analyzes the parameters affecting aqueous humor (AH) outflow and the impact of the uveoscleral pathway on drug transport. Results indicate that the uveoscleral pathway influences AH outflow, with its porous media significantly impeding drug clearance, leading to drug accumulation in the anterior chamber and higher concentrations in the TM. A reduction in TM porosity or the number of CC hinders drug transport to varying extents, increasing peak drug concentration at TM targets by 11.27% and 12.8%, respectively. Furthermore, neglecting the uveoscleral pathway may result in an 10.93% underestimation of TM drug concentration. This study provides insight into the pathways involved in anti-glaucoma drug transport, contributing to the optimization of drug design for improved therapeutic outcomes.

The influences of interactions between copper plate and nano-water droplets on wettability with different solid–liquid potential parameters were studied, and the spread of droplets was compared and analyzed using the molecular dynamics method. The diameter of droplet spreading and the amount of water molecules adsorbed on the copper gradually increased with the potential parameters, whereas the absolute potential energy value between copper and water also increased. Negative potential energy represents the attraction force between solid atoms and liquid molecules, and the attraction grows stronger with the large absolute value of negative potential energy. The heat transfer performance of the wettability surface can be explained by analyzing the force of solid and liquid from the perspective of energy. These results are of great significance for establishing the wettability model of a smooth plate correctly and the design and manufacture of a special functional surface.

Boiling heat transfer on nanostructured surfaces presents great potential in cooling highly integrated microelectronic devices. Analysis of the factors affecting boiling heat transfer included the analysis of nanostructure and wettability, indicating that consideration of the influence of working liquid quantity is essential in finite spaces. Rapid boiling water films with various thicknesses placed on the same nanochannel copper plate were studied via molecular dynamics (MD) simulations. The simulation results reveal that the potential energy difference in the vapor–liquid coexisting region on the nanochannels was lower for thicker films, and the evaporation rate was lower. The effect of water film thickness on boiling heat transfer is closely related to the potential energy difference in the vapor–liquid coexisting region on the nanochannels. The heat transfer effect was the worst in case 1, where the water thickness was lower than the height of the nanochannels. This is because there is no guaranteed liquid replenishment at the nucleation points, although the potential energy difference was greatest in the vapor–liquid coexistence zone of case 1. Evaporation was the greatest in case 2, where the water film just covered the nanochannels because of the larger potential energy difference and sufficient liquid water replenishment. This study is of great significance for the analysis of the vapor–liquid flow mechanisms of micro/nanostructured surfaces and the improved design of thermal management equipment of micro/nano devices.