Determination of droplet sizes in a gas-droplet outflow from a microchannel nozzle
E.Ya. Gatapova1,2,3, M.N. Ryabov2
1Novosibirsk State Univeristy, Novosibirsk, Russia
2Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
3Lomonosov Moscow State University, Moscow, Russia
Keywords: gas-droplet flow, nozzle, spray, microchannel membrane, microdroplets, high resolution, high-speed imaging
Abstract
To generate a spray flow in confined spaces, specialized nozzles are required to disperse micron- and submicron-sized droplets at the nozzle edge. High-speed visualization of a gas-droplet flow from a custom-made microchannel nozzle device with a resolution of 2.5 μm/pixel was performed, allowing the sizes of the dispersed droplets to be determined. The nozzle device was a custom-made device with a 243 μm thick microchannel silicon membrane and a microchannel size of 10×10 μm2. Measurements of the characteristic dimensions were conducted and the velocities of the dispersed droplets were determined at low liquid flow rates (0.05-2 ml/min) and air pressure differences from 1 to 6 atm. At HFE-7100 flow rate of 1 ml/min and an air pressure differential of 1 atm, the average droplet size was approximately 40 μm, while at a flow rate of 2 ml/min and a pressure differential of 2 atm, the average droplet size was 20 μm. A significant increase in velocity was observed with increasing pressure differential. At the minimum flow rate, very small droplets were dispersed, which were not detected at a resolution of 2.5 μm/pixel, but the overall flow was clearly visible as a "mist."
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