Keywords

Micronozzle, Microthruster, Vacuum

Presentation Type

Event

Research Abstract

A major consideration in microsatellite design is the engineering of micropropulsion systems that can deliver the required thrust efficiently with tight restrictions on space, weight, and power. Cold gas thrusters are one solution to the demand for smaller propulsion systems to accommodate the advancements in technology that have allowed for a reduction in the size and thus the cost of satellites. While much research has been done in understanding the flow regimes within these microthrusters, there is a need to understand how different nozzle designs affect microthruster performance. This requires that experimental data be collected on varying nozzles shapes (orifices, channels, and an annulus). Tests will be done in high vacuum conditions with varying thruster plenum pressures and with Nitrogen as the propellant. Temperature will be measured in both the thruster plenum and the vacuum chamber, while thrust will be measured using a micronewton torsional balance. The nozzles will be compared after calculating the specific impulse, thrust coefficient, discharge coefficient, and Knudsen number for each at the various plenum pressures. The plug array is expected to be the most efficient with a theoretical specific impulse that is higher than the other nozzles to be tested. The plug array design was found, during stochastic numerical simulations, to have enhanced performance through increased pressure thrust, a desirable attribute in low Reynolds number flows. The results from this research will be used to further develop the most efficient systems for attitude control on microsatellites.

Session Track

Earth and Space Sciences

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Aug 7th, 12:00 AM

Microthruster Fabrication and Characterization: In Search of the Optimal Nozzle Geometry for Microscale Rocket Engines

A major consideration in microsatellite design is the engineering of micropropulsion systems that can deliver the required thrust efficiently with tight restrictions on space, weight, and power. Cold gas thrusters are one solution to the demand for smaller propulsion systems to accommodate the advancements in technology that have allowed for a reduction in the size and thus the cost of satellites. While much research has been done in understanding the flow regimes within these microthrusters, there is a need to understand how different nozzle designs affect microthruster performance. This requires that experimental data be collected on varying nozzles shapes (orifices, channels, and an annulus). Tests will be done in high vacuum conditions with varying thruster plenum pressures and with Nitrogen as the propellant. Temperature will be measured in both the thruster plenum and the vacuum chamber, while thrust will be measured using a micronewton torsional balance. The nozzles will be compared after calculating the specific impulse, thrust coefficient, discharge coefficient, and Knudsen number for each at the various plenum pressures. The plug array is expected to be the most efficient with a theoretical specific impulse that is higher than the other nozzles to be tested. The plug array design was found, during stochastic numerical simulations, to have enhanced performance through increased pressure thrust, a desirable attribute in low Reynolds number flows. The results from this research will be used to further develop the most efficient systems for attitude control on microsatellites.