Numerical Study of 3D E↵ects on Dispersed Monopropellant Slug Formation at a Micro-Scale Cross Junction

Gas and liquid converging at a microchannel cross junction results in the formation of periodic, dispersed microslugs. This microslug formation phenomena has been proposed as the basis for a fuel injection system in a novel, discrete monopropellant microthruster design for use in next-generation miniaturized satellites. Experimental work by McCabe et al. 1 demonstrated the ability to generate fuel slugs with characteristics commensurate with the intended application. In this study, a computational model of the microchannel junction is used to investigate the e↵ects of channel depth on the formation process and characteristics of fuel slugs. The simulations show the relative slug volume and detachment location increase with channel depth. Over the range of depths studied, the relative slug volume increased by up to 20% and the detachment location increased by 10 channel widths. These results demonstrate the impact of 3D e↵ects on the ability of the system to throttle the fuel flow rate to a level necessary for low thrust applications, which will have ramifications on the design and manufacture of the microthruster system.