Study of Two-Phase Microslug Formation in a Microchannel Cross Junction

M.R. McDevitt, D.L. Hitt, and J.W. McCabe
University of Vermont, Burlington, VT, USA
Published in 2010

NASA and the Department of Defense have interest in the development of satellites which are several orders of magnitude smaller than those currently in use. These ‘nanosats’ will require new propulsion systems to offer precise thrust and impulse-bit characteristics on the order of 10-100 μN and 100-1000 μNs respectively. To meet these demands, a pressure-driven MEMS-based monopropellant thruster has been proposed by NASA GSFC. By controlling the size and frequency of these fuel microslugs, the resulting thrust and impulse-bit characteristics can meet the design requirements. The goal of the present study is a numerical investigation of this phenomenon that will facilitate a clearer understanding of the variation of slug characteristics with hydrodynamic properties and material properties. To meet these goals, the level set method as implemented in the MEMS Module of COMSOL Multiphysics 3.5a was used to simulate the microslug formation at the cross junction. Initial results of these simulations correspond well with the results of flow visualization experiments.