Catalytic Tubular Microjet Navigating in Confined Microfluidic Channels: Modeling and Optimization

This paper describes the propulsion of the catalytic tubular microjet in confined environments as microchannels and capillaries using the Stokes equations. Especially, the thrust capability of the microjet is outstanding compared with the other microsystems, but remains only partially understood. Studies have identified the internal precursory mechanisms of the propulsion of the microjet: its inner wall catalyzes the dismutation of the fuel and bubbles are then formed. Since the jet is conical, the bubble migrates towards its widest opening. This impulses the propulsion of the microjet towards the opposite direction. However, the precise propellant role of the liquid surrounding the jet remains misunderstood. The same goes for the inner wall of the vessel in which the jet navigates, especially in narrowed environment. This article discusses these aspects in a simplified theoretical framework. Calculations are performed by explicit computation of the Stokes equations. The obtained theoretical results are in good agreement with experimental results reported in the literature.