Hydrodynamic characteristics of an evaporation-based micro-synthetic jet for micro-propulsion

In this study, a concept of using a synthetic jet for micro-propulsion is introduced. The system has no moving parts and operates based on a periodic process associated with bubble growth and collapse on a micro-heater in a confined chamber. The liquid is propelled through a micro-nozzle located at the chamber exit using the interfacial layer movement between the vapor and liquid phases during the bubble growth. High-speed photography and image processing are used to capture the sequence of bubble ebullition in the chamber. The synthetic jet velocity at the nozzle exit is then numerically simulated using SST k-omega turbulence model and it is shown that the thrust during the ejection phase is two orders of magnitude greater than the rest of the cycle, resulting in a positive net momentum. Comparing the operating power of different types of micro-thrusters revealed that the introduced approach is one of the lowest powered micro-thrusters.