A Numerical Study of Sub-Millisecond Integrated Mix-and-Inject Microfluidic Devices for Sample Delivery at Synchrotron and XFELs

Microfluidic devices which integrate both rapid mixing and liquid jetting for sample delivery are an emerging solution studying molecular dynamics via X-ray diffraction. Here we use finite element modelling to investigate the efficiency time-resolution achievable using microfluidic mixers within parameter range required producing stable jets. Three-dimensional simulations, validated by experimental data, used determine velocity concentration distribution these devices. The results show that adopting a serpentine geometry, it is possible induce chaotic mixing, effectively reduces time achieve homogeneous mixture delivery. Further, effect of flow rate mixer microchannel size on minimum complete two solutions whilst maintaining jet. In general, find smaller cross-sectional area microchannel, shorter needed given rate. simulations will form basis optimised designs enabling study occurring millisecond timescales integrated mix-and-inject