A Micro-Scale Monopropellant Fuel Injection Scheme Using Two-Phase Slug Formation

The periodic formation of dispersed microscopic liquid slugs (microslugs) at a microchannel junction is investigated as a means for enhancing precision and control of fuel delivery in monopropellant-based micropropulsion systems. Slug length and frequency of production are determined by digital image analysis of high-speed videomicroscopy recordings of the formation process in a microchannel (hydraulic diameter 28 ) under varying inlet pressure conditions. Experimental findings show that a range of slug characteristics are possible, with sizes spanning 0.05–1.7 mm at corresponding formation frequencies of 39–397 Hz. For a hydrogen-peroxide monopropellant fuel, it is estimated that the associated impulse bit of a singlemicroslug can range from 0:2–3 N s, which demonstrates the potential utility for micropropulsion applications.