The Research Of Colloid Thruster Performance And Its Micromation Design

Micro-satellites require that thrusters can provideμN level thrust,so conventional thrusters become a bottleneck in the development of micro-satellites. MEMS colloid thruster array can meet the thruster index requirements of small size and high specific impulse. In this paper, the design of micro colloid thruster array was researched. The method of theoretical calculation and simulation was used to decide the basic dimensions. Micro fabrication process was chose depending on the structure. In the last, the testing results of vacuum and normal atmosphere were expounded.When the emitter was loaded with high voltage, the process of the liquid charging and relaxation was analyzed, the surface charge was calculated, and when the surface field was bigger than the surface tension, the droplets were emitted out. Multi-jets model was established, on the process of increasing voltage, the strongest electric field was shifted from the center to the fringe of capillary. The thrust and specific impulse were calculated and the injection efficiency was derivate.The methods of increasing the life of thrusters were researched. Electrochemical reaction was unavoidable when the propellant worked long hours under high voltage. Pure propellant and inert electrodes can ensure stable work in a certain period of time, and exchanging electrode voltage can totally avoid electrochemical reaction. The way of imposed voltage affected the efficiency of jet propulsion. Absolute high voltage was loaded on the emitter and the ground voltage on the extractor is the most efficient way. Nozzle distance was determined according to the electric field strength. Considering the MEMS fabrication level, the feasible fabrication process was designed. The mask versions were designed by use of the L-editor software. Testing the thruster in the air and the vacuum verified the thruster life analyses, the way of applying voltage, multi-jet and the breakdown characteristics and it made the foundation for the design of the thruster system.The innovations of this paper are as follows. 1: In the design process the emitter distance was first considered. Through computing, simulation and test, the emitters distance was got and it should be seven to eight times as large as the emitter diameter. 2: The array emitters required the uniformity of the electric field. In the premise of the largest integrated intensity the grid extractor bring a uniform electric field. 3 The middle insulation layer was the Pyrex glass which was made by machining ensured the insulation effect and also satisfied synchronization of MEMS manufacturing process.