A Simple Thermoelectric Droplet Generator
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A new design for a droplet generator capable of producing single droplets is presented. The design relies on thermoelectric heating to vaporize water at the interface between a droplet and a blunt syringe tip. While other designs require careful tuning to produce drops of varying size, this technique enables the simple creation of droplets of any size within a range. The design is of simple construction and can be completed with off-the-shelf components, and relies on resistive heating to vaporize water at or near the droplet-nozzle interface and release the droplets. We demonstrated that the design can be used to produce droplets as small as 110 μm or as large as 2 mm. Drop size is limited by the geometry of the nozzle since water must wet the tip of the nozzle and hang under gravity. Our experiments showed that released droplets have relatively small disturbances introduced by the release mechanism when compared to competing techniques. These disturbances were intermittently observed as the voltage, pulse width, and drop size were changed, and optimal settings were determined for the smallest drop sizes produced.
KeywordsDroplet Droplet generator Droplet experiment Water Thermoelectric Surface tension
The efforts reported in this paper were supported by the NASA Advanced Air Transportation Technology (AATT) Project and the NASA Revolutionary Vertical Lift Technology (RVLT) Project. Any opinions presented in this paper are those of the authors and do not reflect the views of NASA or the United States government.
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