| Summary: | 碩士 === 國立成功大學 === 航空太空工程學系 === 87 === This thesis research has completed the design, fabrication and hot firing tests of a 1-lbf-monopropellant hydrazine thrusters. The design of this thruster is based on the experimental data from previous research in this laboratory. This 1-lbf thruster was equipped with single-tube radial type 9- and 16-orifice and axially porous disk type injectors, and packed with 7.4g and 8.1g Shell 405 catalyst. After 33 ground tests (1atm backpressure) of seven thruster configuration, the results showed:
(1) At the propellant flow rate around 0.005lbm/sec, the 9-orifice radial type thrusters produced 112.3~131.5psia chamber pressure. It was 30% less than the expectation. But the others produced 198.0~220.2psia chamber pressure. It was 8% more than the expectation. The 16-orifice radial type thruster packed with 8.1g catalyst produced the chamber pressure of 220.2psia, sea-level thrust of ~0.63lbf, and specific impulse of ~126sec, which was the best performance for all the thrust''s configurations.
(2) Through theoretical calculations of the ideal vacuum thrust based on chamber pressure, the radial type (16-orifice) and disk type thrusters could obtain ideal vacuum thrust of ~1.0lbf and the ideal specific impulse of ~200sec at the propellant flow rate around 0.005lbm/sec.
(3) The response time of the radial type (16-orifice) thrusters and porous disk type thrusters were 42~82ms. Compared to the commercial hydrazine thrusters, it was 2 or 3 folds longer and required to be further researched and shortened.
(4) The shorter the pulse duration of the thruster operation, the radial type (16-orifice) and disk type thrusters showed higher amount of total impulse. The 16-orifice and 8.1g catalyst configuration gave the higher total impulse indicated its better response characteristics.
These experimental results showed that the injector design affected the response characteristics of hydrazine thruster pronounced. To further improve the response characteristics of hydrazine thruster, researching on multi-tube or spiral-tube radial type injectors in order to better utilizing the catalyst surface for hydrazine dissociation is recommended.
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