Investigation on the Physics and Microfluidics of the Decomposition of Hydrogen Peroxide in MEMS Microthrusters
Technical Report,01 Dec 2015,30 Nov 2016
ALMA MATER STUDIORUM UNIVERSITA' DI BOLOGNA SEDE BOLOGNA Italy
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We performed a numerical investigation of the microfluidics within peroxide monopropellant microthrusters. One of the challenges with microscale thrusters is that, as the size is reduced, the ratio of the surface area to volume increases. Therefore, the heat losses surface phenomenon become significant compared to the heat generated by the exothermic reaction within the device volume phenomenon,and the thermal energy available inside the combustion chamber may not be sufficient for sustaining the reaction and vaporization of the liquid products and non-reacted propellant. To gain more insight over the complex interactions within the combustion chamber, we developed a numerical model which jointly analyzes the chemical, fluid-dynamics and thermal behavior of the propellant stream inside the combustion chamber, as well as the thermal coupling with a conductive substrate. Within this model, evaporation is handled by making use of a variable heat capacity method and the concept of pseudo-phase. This method offers a sound way to model the evaporation in a chemical reacting mixture. As a main result, it emerged that the substrate has a great impact on the flow evolution, with an evaporation region distributed all over the length of the device, affecting also the propellant conversion rate.
- Fluidics and Fluerics