Micro-propeller Structure And Production Process

Micro thruster is a new kind of micro propulsion system based on MEMS(Micro-Electro-Mechanical System), which is mainly used in micro spacecraft for keeping position, controlling orientation and adjusting orbit. Design, fabrication and test of the micro thruster were introduced in this thesis. A principle prototype was fabricated, which integrated a 4×6 array of micro thruster units on a 9mm×9mm square wafer. The temperature distributions of the ignition resisters and combustion chambers were simulated by ANSYS software.A micro thruster was composed of the bottom ignition circuit, the middle combustion chamber and the top nozzle. The ignition circuit was prepared on a glass substrate by magnetron-sputtering, lithography and wet etching. The 4×6 array of combustion chambers was fabricated in an epoxy resin sheet by machining process. The laval-nozzle-like layer was fabricated by LPCVD, RIE and wet etching. Three parts were assembled into the principle prototype.The fire performances of the ignition circuits, which were prepared under different conditions, were tested. The melting time of the ignition resister decreased exponentially with increasing the voltage. When the voltage was 10 V or 30 V, the melting time of the ignition resister, which was prepared under the power of 150 W and the time of 30 min, was about 225 ms or 10μs, respectively.Furthermore, micro thrust was tested by loading AP/NHN and AP/THPC under different combustion chamber diameters. AP/NHN (80/20) possessed the best performances of micro thrust, thrust time and impulse. The combustion duration was more than 146 ms, the impulse was more than 30μN·s, especially, which ignition ratio was high.The temperature distributions of the ignition resisters and combustion chambers were simulated by ANSYS software. The results show that the temperature of the resister could reach to the ignition temperatures of conventional propellants within 10 ms-20 ms. The simulated temperature distributions on the ignition resisters surface accorded with the results of the experiments. It also was found that the ignition in a chamber didn't affect other adjacent chambers when epoxy resin and 7740-type glass were chosen to be the material of the combustion chamber.